| /* |
| * Driver for AMBA serial ports |
| * |
| * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. |
| * |
| * Copyright 1999 ARM Limited |
| * Copyright (C) 2000 Deep Blue Solutions Ltd. |
| * Copyright (C) 2010 ST-Ericsson SA |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| * This is a generic driver for ARM AMBA-type serial ports. They |
| * have a lot of 16550-like features, but are not register compatible. |
| * Note that although they do have CTS, DCD and DSR inputs, they do |
| * not have an RI input, nor do they have DTR or RTS outputs. If |
| * required, these have to be supplied via some other means (eg, GPIO) |
| * and hooked into this driver. |
| */ |
| |
| #if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) |
| #define SUPPORT_SYSRQ |
| #endif |
| |
| #include <linux/module.h> |
| #include <linux/ioport.h> |
| #include <linux/init.h> |
| #include <linux/console.h> |
| #include <linux/sysrq.h> |
| #include <linux/device.h> |
| #include <linux/tty.h> |
| #include <linux/tty_flip.h> |
| #include <linux/serial_core.h> |
| #include <linux/serial.h> |
| #include <linux/amba/bus.h> |
| #include <linux/amba/serial.h> |
| #include <linux/clk.h> |
| #include <linux/slab.h> |
| #include <linux/dmaengine.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/scatterlist.h> |
| #include <linux/delay.h> |
| |
| #include <asm/io.h> |
| #include <asm/sizes.h> |
| |
| #define UART_NR 14 |
| |
| #define SERIAL_AMBA_MAJOR 204 |
| #define SERIAL_AMBA_MINOR 64 |
| #define SERIAL_AMBA_NR UART_NR |
| |
| #define AMBA_ISR_PASS_LIMIT 256 |
| |
| #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE) |
| #define UART_DUMMY_DR_RX (1 << 16) |
| |
| |
| #define UART_WA_SAVE_NR 14 |
| |
| static void pl011_lockup_wa(unsigned long data); |
| static const u32 uart_wa_reg[UART_WA_SAVE_NR] = { |
| ST_UART011_DMAWM, |
| ST_UART011_TIMEOUT, |
| ST_UART011_LCRH_RX, |
| UART011_IBRD, |
| UART011_FBRD, |
| ST_UART011_LCRH_TX, |
| UART011_IFLS, |
| ST_UART011_XFCR, |
| ST_UART011_XON1, |
| ST_UART011_XON2, |
| ST_UART011_XOFF1, |
| ST_UART011_XOFF2, |
| UART011_CR, |
| UART011_IMSC |
| }; |
| |
| static u32 uart_wa_regdata[UART_WA_SAVE_NR]; |
| static DECLARE_TASKLET(pl011_lockup_tlet, pl011_lockup_wa, 0); |
| |
| /* There is by now at least one vendor with differing details, so handle it */ |
| struct vendor_data { |
| unsigned int ifls; |
| unsigned int fifosize; |
| unsigned int lcrh_tx; |
| unsigned int lcrh_rx; |
| bool oversampling; |
| bool interrupt_may_hang; /* vendor-specific */ |
| bool dma_threshold; |
| }; |
| |
| static struct vendor_data vendor_arm = { |
| .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8, |
| .fifosize = 16, |
| .lcrh_tx = UART011_LCRH, |
| .lcrh_rx = UART011_LCRH, |
| .oversampling = false, |
| .dma_threshold = false, |
| }; |
| |
| static struct vendor_data vendor_st = { |
| .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF, |
| .fifosize = 64, |
| .lcrh_tx = ST_UART011_LCRH_TX, |
| .lcrh_rx = ST_UART011_LCRH_RX, |
| .oversampling = true, |
| .interrupt_may_hang = true, |
| .dma_threshold = true, |
| }; |
| |
| static struct uart_amba_port *amba_ports[UART_NR]; |
| |
| /* Deals with DMA transactions */ |
| |
| struct pl011_sgbuf { |
| struct scatterlist sg; |
| char *buf; |
| }; |
| |
| struct pl011_dmarx_data { |
| struct dma_chan *chan; |
| struct completion complete; |
| bool use_buf_b; |
| struct pl011_sgbuf sgbuf_a; |
| struct pl011_sgbuf sgbuf_b; |
| dma_cookie_t cookie; |
| bool running; |
| }; |
| |
| struct pl011_dmatx_data { |
| struct dma_chan *chan; |
| struct scatterlist sg; |
| char *buf; |
| bool queued; |
| }; |
| |
| /* |
| * We wrap our port structure around the generic uart_port. |
| */ |
| struct uart_amba_port { |
| struct uart_port port; |
| struct clk *clk; |
| const struct vendor_data *vendor; |
| unsigned int dmacr; /* dma control reg */ |
| unsigned int im; /* interrupt mask */ |
| unsigned int old_status; |
| unsigned int fifosize; /* vendor-specific */ |
| unsigned int lcrh_tx; /* vendor-specific */ |
| unsigned int lcrh_rx; /* vendor-specific */ |
| bool autorts; |
| char type[12]; |
| bool interrupt_may_hang; /* vendor-specific */ |
| #ifdef CONFIG_DMA_ENGINE |
| /* DMA stuff */ |
| bool using_tx_dma; |
| bool using_rx_dma; |
| struct pl011_dmarx_data dmarx; |
| struct pl011_dmatx_data dmatx; |
| #endif |
| }; |
| |
| /* |
| * Reads up to 256 characters from the FIFO or until it's empty and |
| * inserts them into the TTY layer. Returns the number of characters |
| * read from the FIFO. |
| */ |
| static int pl011_fifo_to_tty(struct uart_amba_port *uap) |
| { |
| u16 status, ch; |
| unsigned int flag, max_count = 256; |
| int fifotaken = 0; |
| |
| while (max_count--) { |
| status = readw(uap->port.membase + UART01x_FR); |
| if (status & UART01x_FR_RXFE) |
| break; |
| |
| /* Take chars from the FIFO and update status */ |
| ch = readw(uap->port.membase + UART01x_DR) | |
| UART_DUMMY_DR_RX; |
| flag = TTY_NORMAL; |
| uap->port.icount.rx++; |
| fifotaken++; |
| |
| if (unlikely(ch & UART_DR_ERROR)) { |
| if (ch & UART011_DR_BE) { |
| ch &= ~(UART011_DR_FE | UART011_DR_PE); |
| uap->port.icount.brk++; |
| if (uart_handle_break(&uap->port)) |
| continue; |
| } else if (ch & UART011_DR_PE) |
| uap->port.icount.parity++; |
| else if (ch & UART011_DR_FE) |
| uap->port.icount.frame++; |
| if (ch & UART011_DR_OE) |
| uap->port.icount.overrun++; |
| |
| ch &= uap->port.read_status_mask; |
| |
| if (ch & UART011_DR_BE) |
| flag = TTY_BREAK; |
| else if (ch & UART011_DR_PE) |
| flag = TTY_PARITY; |
| else if (ch & UART011_DR_FE) |
| flag = TTY_FRAME; |
| } |
| |
| if (uart_handle_sysrq_char(&uap->port, ch & 255)) |
| continue; |
| |
| uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag); |
| } |
| |
| return fifotaken; |
| } |
| |
| |
| /* |
| * All the DMA operation mode stuff goes inside this ifdef. |
| * This assumes that you have a generic DMA device interface, |
| * no custom DMA interfaces are supported. |
| */ |
| #ifdef CONFIG_DMA_ENGINE |
| |
| #define PL011_DMA_BUFFER_SIZE PAGE_SIZE |
| |
| static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg, |
| enum dma_data_direction dir) |
| { |
| sg->buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL); |
| if (!sg->buf) |
| return -ENOMEM; |
| |
| sg_init_one(&sg->sg, sg->buf, PL011_DMA_BUFFER_SIZE); |
| |
| if (dma_map_sg(chan->device->dev, &sg->sg, 1, dir) != 1) { |
| kfree(sg->buf); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg, |
| enum dma_data_direction dir) |
| { |
| if (sg->buf) { |
| dma_unmap_sg(chan->device->dev, &sg->sg, 1, dir); |
| kfree(sg->buf); |
| } |
| } |
| |
| static void pl011_dma_probe_initcall(struct uart_amba_port *uap) |
| { |
| /* DMA is the sole user of the platform data right now */ |
| struct amba_pl011_data *plat = uap->port.dev->platform_data; |
| struct dma_slave_config tx_conf = { |
| .dst_addr = uap->port.mapbase + UART01x_DR, |
| .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, |
| .direction = DMA_TO_DEVICE, |
| .dst_maxburst = uap->fifosize >> 1, |
| }; |
| struct dma_chan *chan; |
| dma_cap_mask_t mask; |
| |
| /* We need platform data */ |
| if (!plat || !plat->dma_filter) { |
| dev_info(uap->port.dev, "no DMA platform data\n"); |
| return; |
| } |
| |
| /* Try to acquire a generic DMA engine slave TX channel */ |
| dma_cap_zero(mask); |
| dma_cap_set(DMA_SLAVE, mask); |
| |
| chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param); |
| if (!chan) { |
| dev_err(uap->port.dev, "no TX DMA channel!\n"); |
| return; |
| } |
| |
| dmaengine_slave_config(chan, &tx_conf); |
| uap->dmatx.chan = chan; |
| |
| dev_info(uap->port.dev, "DMA channel TX %s\n", |
| dma_chan_name(uap->dmatx.chan)); |
| |
| /* Optionally make use of an RX channel as well */ |
| if (plat->dma_rx_param) { |
| struct dma_slave_config rx_conf = { |
| .src_addr = uap->port.mapbase + UART01x_DR, |
| .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, |
| .direction = DMA_FROM_DEVICE, |
| .src_maxburst = uap->fifosize >> 1, |
| }; |
| |
| chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param); |
| if (!chan) { |
| dev_err(uap->port.dev, "no RX DMA channel!\n"); |
| return; |
| } |
| |
| dmaengine_slave_config(chan, &rx_conf); |
| uap->dmarx.chan = chan; |
| |
| dev_info(uap->port.dev, "DMA channel RX %s\n", |
| dma_chan_name(uap->dmarx.chan)); |
| } |
| } |
| |
| #ifndef MODULE |
| /* |
| * Stack up the UARTs and let the above initcall be done at device |
| * initcall time, because the serial driver is called as an arch |
| * initcall, and at this time the DMA subsystem is not yet registered. |
| * At this point the driver will switch over to using DMA where desired. |
| */ |
| struct dma_uap { |
| struct list_head node; |
| struct uart_amba_port *uap; |
| }; |
| |
| static LIST_HEAD(pl011_dma_uarts); |
| |
| static int __init pl011_dma_initcall(void) |
| { |
| struct list_head *node, *tmp; |
| |
| list_for_each_safe(node, tmp, &pl011_dma_uarts) { |
| struct dma_uap *dmau = list_entry(node, struct dma_uap, node); |
| pl011_dma_probe_initcall(dmau->uap); |
| list_del(node); |
| kfree(dmau); |
| } |
| return 0; |
| } |
| |
| device_initcall(pl011_dma_initcall); |
| |
| static void pl011_dma_probe(struct uart_amba_port *uap) |
| { |
| struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL); |
| if (dmau) { |
| dmau->uap = uap; |
| list_add_tail(&dmau->node, &pl011_dma_uarts); |
| } |
| } |
| #else |
| static void pl011_dma_probe(struct uart_amba_port *uap) |
| { |
| pl011_dma_probe_initcall(uap); |
| } |
| #endif |
| |
| static void pl011_dma_remove(struct uart_amba_port *uap) |
| { |
| /* TODO: remove the initcall if it has not yet executed */ |
| if (uap->dmatx.chan) |
| dma_release_channel(uap->dmatx.chan); |
| if (uap->dmarx.chan) |
| dma_release_channel(uap->dmarx.chan); |
| } |
| |
| /* Forward declare this for the refill routine */ |
| static int pl011_dma_tx_refill(struct uart_amba_port *uap); |
| |
| /* |
| * The current DMA TX buffer has been sent. |
| * Try to queue up another DMA buffer. |
| */ |
| static void pl011_dma_tx_callback(void *data) |
| { |
| struct uart_amba_port *uap = data; |
| struct pl011_dmatx_data *dmatx = &uap->dmatx; |
| unsigned long flags; |
| u16 dmacr; |
| |
| spin_lock_irqsave(&uap->port.lock, flags); |
| if (uap->dmatx.queued) |
| dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1, |
| DMA_TO_DEVICE); |
| |
| dmacr = uap->dmacr; |
| uap->dmacr = dmacr & ~UART011_TXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| |
| /* |
| * If TX DMA was disabled, it means that we've stopped the DMA for |
| * some reason (eg, XOFF received, or we want to send an X-char.) |
| * |
| * Note: we need to be careful here of a potential race between DMA |
| * and the rest of the driver - if the driver disables TX DMA while |
| * a TX buffer completing, we must update the tx queued status to |
| * get further refills (hence we check dmacr). |
| */ |
| if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) || |
| uart_circ_empty(&uap->port.state->xmit)) { |
| uap->dmatx.queued = false; |
| spin_unlock_irqrestore(&uap->port.lock, flags); |
| return; |
| } |
| |
| if (pl011_dma_tx_refill(uap) <= 0) { |
| /* |
| * We didn't queue a DMA buffer for some reason, but we |
| * have data pending to be sent. Re-enable the TX IRQ. |
| */ |
| uap->im |= UART011_TXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } |
| spin_unlock_irqrestore(&uap->port.lock, flags); |
| } |
| |
| /* |
| * Try to refill the TX DMA buffer. |
| * Locking: called with port lock held and IRQs disabled. |
| * Returns: |
| * 1 if we queued up a TX DMA buffer. |
| * 0 if we didn't want to handle this by DMA |
| * <0 on error |
| */ |
| static int pl011_dma_tx_refill(struct uart_amba_port *uap) |
| { |
| struct pl011_dmatx_data *dmatx = &uap->dmatx; |
| struct dma_chan *chan = dmatx->chan; |
| struct dma_device *dma_dev = chan->device; |
| struct dma_async_tx_descriptor *desc; |
| struct circ_buf *xmit = &uap->port.state->xmit; |
| unsigned int count; |
| |
| /* |
| * Try to avoid the overhead involved in using DMA if the |
| * transaction fits in the first half of the FIFO, by using |
| * the standard interrupt handling. This ensures that we |
| * issue a uart_write_wakeup() at the appropriate time. |
| */ |
| count = uart_circ_chars_pending(xmit); |
| if (count < (uap->fifosize >> 1)) { |
| uap->dmatx.queued = false; |
| return 0; |
| } |
| |
| /* |
| * Bodge: don't send the last character by DMA, as this |
| * will prevent XON from notifying us to restart DMA. |
| */ |
| count -= 1; |
| |
| /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */ |
| if (count > PL011_DMA_BUFFER_SIZE) |
| count = PL011_DMA_BUFFER_SIZE; |
| |
| if (xmit->tail < xmit->head) |
| memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count); |
| else { |
| size_t first = UART_XMIT_SIZE - xmit->tail; |
| size_t second = xmit->head; |
| |
| memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first); |
| if (second) |
| memcpy(&dmatx->buf[first], &xmit->buf[0], second); |
| } |
| |
| dmatx->sg.length = count; |
| |
| if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) { |
| uap->dmatx.queued = false; |
| dev_dbg(uap->port.dev, "unable to map TX DMA\n"); |
| return -EBUSY; |
| } |
| |
| desc = dma_dev->device_prep_slave_sg(chan, &dmatx->sg, 1, DMA_TO_DEVICE, |
| DMA_PREP_INTERRUPT | DMA_CTRL_ACK); |
| if (!desc) { |
| dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE); |
| uap->dmatx.queued = false; |
| /* |
| * If DMA cannot be used right now, we complete this |
| * transaction via IRQ and let the TTY layer retry. |
| */ |
| dev_dbg(uap->port.dev, "TX DMA busy\n"); |
| return -EBUSY; |
| } |
| |
| /* Some data to go along to the callback */ |
| desc->callback = pl011_dma_tx_callback; |
| desc->callback_param = uap; |
| |
| /* All errors should happen at prepare time */ |
| dmaengine_submit(desc); |
| |
| /* Fire the DMA transaction */ |
| dma_dev->device_issue_pending(chan); |
| |
| uap->dmacr |= UART011_TXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| uap->dmatx.queued = true; |
| |
| /* |
| * Now we know that DMA will fire, so advance the ring buffer |
| * with the stuff we just dispatched. |
| */ |
| xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); |
| uap->port.icount.tx += count; |
| |
| if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) |
| uart_write_wakeup(&uap->port); |
| |
| return 1; |
| } |
| |
| /* |
| * We received a transmit interrupt without a pending X-char but with |
| * pending characters. |
| * Locking: called with port lock held and IRQs disabled. |
| * Returns: |
| * false if we want to use PIO to transmit |
| * true if we queued a DMA buffer |
| */ |
| static bool pl011_dma_tx_irq(struct uart_amba_port *uap) |
| { |
| if (!uap->using_tx_dma) |
| return false; |
| |
| /* |
| * If we already have a TX buffer queued, but received a |
| * TX interrupt, it will be because we've just sent an X-char. |
| * Ensure the TX DMA is enabled and the TX IRQ is disabled. |
| */ |
| if (uap->dmatx.queued) { |
| uap->dmacr |= UART011_TXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| uap->im &= ~UART011_TXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| return true; |
| } |
| |
| /* |
| * We don't have a TX buffer queued, so try to queue one. |
| * If we successfully queued a buffer, mask the TX IRQ. |
| */ |
| if (pl011_dma_tx_refill(uap) > 0) { |
| uap->im &= ~UART011_TXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| return true; |
| } |
| return false; |
| } |
| |
| /* |
| * Stop the DMA transmit (eg, due to received XOFF). |
| * Locking: called with port lock held and IRQs disabled. |
| */ |
| static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) |
| { |
| if (uap->dmatx.queued) { |
| uap->dmacr &= ~UART011_TXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| } |
| } |
| |
| /* |
| * Try to start a DMA transmit, or in the case of an XON/OFF |
| * character queued for send, try to get that character out ASAP. |
| * Locking: called with port lock held and IRQs disabled. |
| * Returns: |
| * false if we want the TX IRQ to be enabled |
| * true if we have a buffer queued |
| */ |
| static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) |
| { |
| u16 dmacr; |
| |
| if (!uap->using_tx_dma) |
| return false; |
| |
| if (!uap->port.x_char) { |
| /* no X-char, try to push chars out in DMA mode */ |
| bool ret = true; |
| |
| if (!uap->dmatx.queued) { |
| if (pl011_dma_tx_refill(uap) > 0) { |
| uap->im &= ~UART011_TXIM; |
| ret = true; |
| } else { |
| uap->im |= UART011_TXIM; |
| ret = false; |
| } |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } else if (!(uap->dmacr & UART011_TXDMAE)) { |
| uap->dmacr |= UART011_TXDMAE; |
| writew(uap->dmacr, |
| uap->port.membase + UART011_DMACR); |
| } |
| return ret; |
| } |
| |
| /* |
| * We have an X-char to send. Disable DMA to prevent it loading |
| * the TX fifo, and then see if we can stuff it into the FIFO. |
| */ |
| dmacr = uap->dmacr; |
| uap->dmacr &= ~UART011_TXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| |
| if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) { |
| /* |
| * No space in the FIFO, so enable the transmit interrupt |
| * so we know when there is space. Note that once we've |
| * loaded the character, we should just re-enable DMA. |
| */ |
| return false; |
| } |
| |
| writew(uap->port.x_char, uap->port.membase + UART01x_DR); |
| uap->port.icount.tx++; |
| uap->port.x_char = 0; |
| |
| /* Success - restore the DMA state */ |
| uap->dmacr = dmacr; |
| writew(dmacr, uap->port.membase + UART011_DMACR); |
| |
| return true; |
| } |
| |
| /* |
| * Flush the transmit buffer. |
| * Locking: called with port lock held and IRQs disabled. |
| */ |
| static void pl011_dma_flush_buffer(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| if (!uap->using_tx_dma) |
| return; |
| |
| /* Avoid deadlock with the DMA engine callback */ |
| spin_unlock(&uap->port.lock); |
| dmaengine_terminate_all(uap->dmatx.chan); |
| spin_lock(&uap->port.lock); |
| if (uap->dmatx.queued) { |
| dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1, |
| DMA_TO_DEVICE); |
| uap->dmatx.queued = false; |
| uap->dmacr &= ~UART011_TXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| } |
| } |
| |
| static void pl011_dma_rx_callback(void *data); |
| |
| static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap) |
| { |
| struct dma_chan *rxchan = uap->dmarx.chan; |
| struct dma_device *dma_dev; |
| struct pl011_dmarx_data *dmarx = &uap->dmarx; |
| struct dma_async_tx_descriptor *desc; |
| struct pl011_sgbuf *sgbuf; |
| |
| if (!rxchan) |
| return -EIO; |
| |
| /* Start the RX DMA job */ |
| sgbuf = uap->dmarx.use_buf_b ? |
| &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a; |
| dma_dev = rxchan->device; |
| desc = rxchan->device->device_prep_slave_sg(rxchan, &sgbuf->sg, 1, |
| DMA_FROM_DEVICE, |
| DMA_PREP_INTERRUPT | DMA_CTRL_ACK); |
| /* |
| * If the DMA engine is busy and cannot prepare a |
| * channel, no big deal, the driver will fall back |
| * to interrupt mode as a result of this error code. |
| */ |
| if (!desc) { |
| uap->dmarx.running = false; |
| dmaengine_terminate_all(rxchan); |
| return -EBUSY; |
| } |
| |
| /* Some data to go along to the callback */ |
| desc->callback = pl011_dma_rx_callback; |
| desc->callback_param = uap; |
| dmarx->cookie = dmaengine_submit(desc); |
| dma_async_issue_pending(rxchan); |
| |
| uap->dmacr |= UART011_RXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| uap->dmarx.running = true; |
| |
| uap->im &= ~UART011_RXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| |
| return 0; |
| } |
| |
| /* |
| * This is called when either the DMA job is complete, or |
| * the FIFO timeout interrupt occurred. This must be called |
| * with the port spinlock uap->port.lock held. |
| */ |
| static void pl011_dma_rx_chars(struct uart_amba_port *uap, |
| u32 pending, bool use_buf_b, |
| bool readfifo) |
| { |
| struct tty_struct *tty = uap->port.state->port.tty; |
| struct pl011_sgbuf *sgbuf = use_buf_b ? |
| &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a; |
| struct device *dev = uap->dmarx.chan->device->dev; |
| int dma_count = 0; |
| u32 fifotaken = 0; /* only used for vdbg() */ |
| |
| /* Pick everything from the DMA first */ |
| if (pending) { |
| /* Sync in buffer */ |
| dma_sync_sg_for_cpu(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE); |
| |
| /* |
| * First take all chars in the DMA pipe, then look in the FIFO. |
| * Note that tty_insert_flip_buf() tries to take as many chars |
| * as it can. |
| */ |
| dma_count = tty_insert_flip_string(uap->port.state->port.tty, |
| sgbuf->buf, pending); |
| |
| /* Return buffer to device */ |
| dma_sync_sg_for_device(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE); |
| |
| uap->port.icount.rx += dma_count; |
| if (dma_count < pending) |
| dev_warn(uap->port.dev, |
| "couldn't insert all characters (TTY is full?)\n"); |
| } |
| |
| /* |
| * Only continue with trying to read the FIFO if all DMA chars have |
| * been taken first. |
| */ |
| if (dma_count == pending && readfifo) { |
| /* Clear any error flags */ |
| writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS, |
| uap->port.membase + UART011_ICR); |
| |
| /* |
| * If we read all the DMA'd characters, and we had an |
| * incomplete buffer, that could be due to an rx error, or |
| * maybe we just timed out. Read any pending chars and check |
| * the error status. |
| * |
| * Error conditions will only occur in the FIFO, these will |
| * trigger an immediate interrupt and stop the DMA job, so we |
| * will always find the error in the FIFO, never in the DMA |
| * buffer. |
| */ |
| fifotaken = pl011_fifo_to_tty(uap); |
| } |
| |
| spin_unlock(&uap->port.lock); |
| dev_vdbg(uap->port.dev, |
| "Took %d chars from DMA buffer and %d chars from the FIFO\n", |
| dma_count, fifotaken); |
| tty_flip_buffer_push(tty); |
| spin_lock(&uap->port.lock); |
| } |
| |
| static void pl011_dma_rx_irq(struct uart_amba_port *uap) |
| { |
| struct pl011_dmarx_data *dmarx = &uap->dmarx; |
| struct dma_chan *rxchan = dmarx->chan; |
| struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ? |
| &dmarx->sgbuf_b : &dmarx->sgbuf_a; |
| size_t pending; |
| struct dma_tx_state state; |
| enum dma_status dmastat; |
| |
| /* |
| * Pause the transfer so we can trust the current counter, |
| * do this before we pause the PL011 block, else we may |
| * overflow the FIFO. |
| */ |
| if (dmaengine_pause(rxchan)) |
| dev_err(uap->port.dev, "unable to pause DMA transfer\n"); |
| dmastat = rxchan->device->device_tx_status(rxchan, |
| dmarx->cookie, &state); |
| if (dmastat != DMA_PAUSED) |
| dev_err(uap->port.dev, "unable to pause DMA transfer\n"); |
| |
| /* Disable RX DMA - incoming data will wait in the FIFO */ |
| uap->dmacr &= ~UART011_RXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| uap->dmarx.running = false; |
| |
| pending = sgbuf->sg.length - state.residue; |
| BUG_ON(pending > PL011_DMA_BUFFER_SIZE); |
| /* Then we terminate the transfer - we now know our residue */ |
| dmaengine_terminate_all(rxchan); |
| |
| /* |
| * This will take the chars we have so far and insert |
| * into the framework. |
| */ |
| pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true); |
| |
| /* Switch buffer & re-trigger DMA job */ |
| dmarx->use_buf_b = !dmarx->use_buf_b; |
| if (pl011_dma_rx_trigger_dma(uap)) { |
| dev_dbg(uap->port.dev, "could not retrigger RX DMA job " |
| "fall back to interrupt mode\n"); |
| uap->im |= UART011_RXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } |
| } |
| |
| static void pl011_dma_rx_callback(void *data) |
| { |
| struct uart_amba_port *uap = data; |
| struct pl011_dmarx_data *dmarx = &uap->dmarx; |
| bool lastbuf = dmarx->use_buf_b; |
| int ret; |
| |
| /* |
| * This completion interrupt occurs typically when the |
| * RX buffer is totally stuffed but no timeout has yet |
| * occurred. When that happens, we just want the RX |
| * routine to flush out the secondary DMA buffer while |
| * we immediately trigger the next DMA job. |
| */ |
| spin_lock_irq(&uap->port.lock); |
| uap->dmarx.running = false; |
| dmarx->use_buf_b = !lastbuf; |
| ret = pl011_dma_rx_trigger_dma(uap); |
| |
| pl011_dma_rx_chars(uap, PL011_DMA_BUFFER_SIZE, lastbuf, false); |
| spin_unlock_irq(&uap->port.lock); |
| /* |
| * Do this check after we picked the DMA chars so we don't |
| * get some IRQ immediately from RX. |
| */ |
| if (ret) { |
| dev_dbg(uap->port.dev, "could not retrigger RX DMA job " |
| "fall back to interrupt mode\n"); |
| uap->im |= UART011_RXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } |
| } |
| |
| /* |
| * Stop accepting received characters, when we're shutting down or |
| * suspending this port. |
| * Locking: called with port lock held and IRQs disabled. |
| */ |
| static inline void pl011_dma_rx_stop(struct uart_amba_port *uap) |
| { |
| /* FIXME. Just disable the DMA enable */ |
| uap->dmacr &= ~UART011_RXDMAE; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| } |
| |
| static void pl011_dma_startup(struct uart_amba_port *uap) |
| { |
| int ret; |
| |
| if (!uap->dmatx.chan) |
| return; |
| |
| uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL); |
| if (!uap->dmatx.buf) { |
| dev_err(uap->port.dev, "no memory for DMA TX buffer\n"); |
| uap->port.fifosize = uap->fifosize; |
| return; |
| } |
| |
| sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE); |
| |
| /* The DMA buffer is now the FIFO the TTY subsystem can use */ |
| uap->port.fifosize = PL011_DMA_BUFFER_SIZE; |
| uap->using_tx_dma = true; |
| |
| if (!uap->dmarx.chan) |
| goto skip_rx; |
| |
| /* Allocate and map DMA RX buffers */ |
| ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a, |
| DMA_FROM_DEVICE); |
| if (ret) { |
| dev_err(uap->port.dev, "failed to init DMA %s: %d\n", |
| "RX buffer A", ret); |
| goto skip_rx; |
| } |
| |
| ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b, |
| DMA_FROM_DEVICE); |
| if (ret) { |
| dev_err(uap->port.dev, "failed to init DMA %s: %d\n", |
| "RX buffer B", ret); |
| pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, |
| DMA_FROM_DEVICE); |
| goto skip_rx; |
| } |
| |
| uap->using_rx_dma = true; |
| |
| skip_rx: |
| /* Turn on DMA error (RX/TX will be enabled on demand) */ |
| uap->dmacr |= UART011_DMAONERR; |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| |
| /* |
| * ST Micro variants has some specific dma burst threshold |
| * compensation. Set this to 16 bytes, so burst will only |
| * be issued above/below 16 bytes. |
| */ |
| if (uap->vendor->dma_threshold) |
| writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16, |
| uap->port.membase + ST_UART011_DMAWM); |
| |
| if (uap->using_rx_dma) { |
| if (pl011_dma_rx_trigger_dma(uap)) |
| dev_dbg(uap->port.dev, "could not trigger initial " |
| "RX DMA job, fall back to interrupt mode\n"); |
| } |
| } |
| |
| static void pl011_dma_shutdown(struct uart_amba_port *uap) |
| { |
| if (!(uap->using_tx_dma || uap->using_rx_dma)) |
| return; |
| |
| /* Disable RX and TX DMA */ |
| while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY) |
| barrier(); |
| |
| spin_lock_irq(&uap->port.lock); |
| uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE); |
| writew(uap->dmacr, uap->port.membase + UART011_DMACR); |
| spin_unlock_irq(&uap->port.lock); |
| |
| if (uap->using_tx_dma) { |
| /* In theory, this should already be done by pl011_dma_flush_buffer */ |
| dmaengine_terminate_all(uap->dmatx.chan); |
| if (uap->dmatx.queued) { |
| dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1, |
| DMA_TO_DEVICE); |
| uap->dmatx.queued = false; |
| } |
| |
| kfree(uap->dmatx.buf); |
| uap->using_tx_dma = false; |
| } |
| |
| if (uap->using_rx_dma) { |
| dmaengine_terminate_all(uap->dmarx.chan); |
| /* Clean up the RX DMA */ |
| pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE); |
| pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE); |
| uap->using_rx_dma = false; |
| } |
| } |
| |
| static inline bool pl011_dma_rx_available(struct uart_amba_port *uap) |
| { |
| return uap->using_rx_dma; |
| } |
| |
| static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) |
| { |
| return uap->using_rx_dma && uap->dmarx.running; |
| } |
| |
| |
| #else |
| /* Blank functions if the DMA engine is not available */ |
| static inline void pl011_dma_probe(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline void pl011_dma_remove(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline void pl011_dma_startup(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline void pl011_dma_shutdown(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap) |
| { |
| return false; |
| } |
| |
| static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) |
| { |
| return false; |
| } |
| |
| static inline void pl011_dma_rx_irq(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline void pl011_dma_rx_stop(struct uart_amba_port *uap) |
| { |
| } |
| |
| static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap) |
| { |
| return -EIO; |
| } |
| |
| static inline bool pl011_dma_rx_available(struct uart_amba_port *uap) |
| { |
| return false; |
| } |
| |
| static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) |
| { |
| return false; |
| } |
| |
| #define pl011_dma_flush_buffer NULL |
| #endif |
| |
| |
| /* |
| * pl011_lockup_wa |
| * This workaround aims to break the deadlock situation |
| * when after long transfer over uart in hardware flow |
| * control, uart interrupt registers cannot be cleared. |
| * Hence uart transfer gets blocked. |
| * |
| * It is seen that during such deadlock condition ICR |
| * don't get cleared even on multiple write. This leads |
| * pass_counter to decrease and finally reach zero. This |
| * can be taken as trigger point to run this UART_BT_WA. |
| * |
| */ |
| static void pl011_lockup_wa(unsigned long data) |
| { |
| struct uart_amba_port *uap = amba_ports[0]; |
| void __iomem *base = uap->port.membase; |
| struct circ_buf *xmit = &uap->port.state->xmit; |
| struct tty_struct *tty = uap->port.state->port.tty; |
| int buf_empty_retries = 200; |
| int loop; |
| |
| /* Stop HCI layer from submitting data for tx */ |
| tty->hw_stopped = 1; |
| while (!uart_circ_empty(xmit)) { |
| if (buf_empty_retries-- == 0) |
| break; |
| udelay(100); |
| } |
| |
| /* Backup registers */ |
| for (loop = 0; loop < UART_WA_SAVE_NR; loop++) |
| uart_wa_regdata[loop] = readl(base + uart_wa_reg[loop]); |
| |
| /* Disable UART so that FIFO data is flushed out */ |
| writew(0x00, uap->port.membase + UART011_CR); |
| |
| /* Soft reset UART module */ |
| if (uap->port.dev->platform_data) { |
| struct amba_pl011_data *plat; |
| |
| plat = uap->port.dev->platform_data; |
| if (plat->reset) |
| plat->reset(); |
| } |
| |
| /* Restore registers */ |
| for (loop = 0; loop < UART_WA_SAVE_NR; loop++) |
| writew(uart_wa_regdata[loop] , |
| uap->port.membase + uart_wa_reg[loop]); |
| |
| /* Initialise the old status of the modem signals */ |
| uap->old_status = readw(uap->port.membase + UART01x_FR) & |
| UART01x_FR_MODEM_ANY; |
| |
| if (readl(base + UART011_MIS) & 0x2) |
| printk(KERN_EMERG "UART_BT_WA: ***FAILED***\n"); |
| |
| /* Start Tx/Rx */ |
| tty->hw_stopped = 0; |
| } |
| |
| static void pl011_stop_tx(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| uap->im &= ~UART011_TXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| pl011_dma_tx_stop(uap); |
| } |
| |
| static void pl011_start_tx(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| if (!pl011_dma_tx_start(uap)) { |
| uap->im |= UART011_TXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } |
| } |
| |
| static void pl011_stop_rx(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM| |
| UART011_PEIM|UART011_BEIM|UART011_OEIM); |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| |
| pl011_dma_rx_stop(uap); |
| } |
| |
| static void pl011_enable_ms(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } |
| |
| static void pl011_rx_chars(struct uart_amba_port *uap) |
| { |
| struct tty_struct *tty = uap->port.state->port.tty; |
| |
| pl011_fifo_to_tty(uap); |
| |
| spin_unlock(&uap->port.lock); |
| tty_flip_buffer_push(tty); |
| /* |
| * If we were temporarily out of DMA mode for a while, |
| * attempt to switch back to DMA mode again. |
| */ |
| if (pl011_dma_rx_available(uap)) { |
| if (pl011_dma_rx_trigger_dma(uap)) { |
| dev_dbg(uap->port.dev, "could not trigger RX DMA job " |
| "fall back to interrupt mode again\n"); |
| uap->im |= UART011_RXIM; |
| } else |
| uap->im &= ~UART011_RXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| } |
| spin_lock(&uap->port.lock); |
| } |
| |
| static void pl011_tx_chars(struct uart_amba_port *uap) |
| { |
| struct circ_buf *xmit = &uap->port.state->xmit; |
| int count; |
| |
| if (uap->port.x_char) { |
| writew(uap->port.x_char, uap->port.membase + UART01x_DR); |
| uap->port.icount.tx++; |
| uap->port.x_char = 0; |
| return; |
| } |
| if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) { |
| pl011_stop_tx(&uap->port); |
| return; |
| } |
| |
| /* If we are using DMA mode, try to send some characters. */ |
| if (pl011_dma_tx_irq(uap)) |
| return; |
| |
| count = uap->fifosize >> 1; |
| do { |
| writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR); |
| xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); |
| uap->port.icount.tx++; |
| if (uart_circ_empty(xmit)) |
| break; |
| } while (--count > 0); |
| |
| if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) |
| uart_write_wakeup(&uap->port); |
| |
| if (uart_circ_empty(xmit)) |
| pl011_stop_tx(&uap->port); |
| } |
| |
| static void pl011_modem_status(struct uart_amba_port *uap) |
| { |
| unsigned int status, delta; |
| |
| status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY; |
| |
| delta = status ^ uap->old_status; |
| uap->old_status = status; |
| |
| if (!delta) |
| return; |
| |
| if (delta & UART01x_FR_DCD) |
| uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD); |
| |
| if (delta & UART01x_FR_DSR) |
| uap->port.icount.dsr++; |
| |
| if (delta & UART01x_FR_CTS) |
| uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS); |
| |
| wake_up_interruptible(&uap->port.state->port.delta_msr_wait); |
| } |
| |
| static irqreturn_t pl011_int(int irq, void *dev_id) |
| { |
| struct uart_amba_port *uap = dev_id; |
| unsigned long flags; |
| unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; |
| int handled = 0; |
| |
| spin_lock_irqsave(&uap->port.lock, flags); |
| |
| status = readw(uap->port.membase + UART011_MIS); |
| if (status) { |
| do { |
| writew(status & ~(UART011_TXIS|UART011_RTIS| |
| UART011_RXIS), |
| uap->port.membase + UART011_ICR); |
| |
| if (status & (UART011_RTIS|UART011_RXIS)) { |
| if (pl011_dma_rx_running(uap)) |
| pl011_dma_rx_irq(uap); |
| else |
| pl011_rx_chars(uap); |
| } |
| if (status & (UART011_DSRMIS|UART011_DCDMIS| |
| UART011_CTSMIS|UART011_RIMIS)) |
| pl011_modem_status(uap); |
| if (status & UART011_TXIS) |
| pl011_tx_chars(uap); |
| |
| if (pass_counter-- == 0) { |
| if (uap->interrupt_may_hang) |
| tasklet_schedule(&pl011_lockup_tlet); |
| break; |
| } |
| |
| status = readw(uap->port.membase + UART011_MIS); |
| } while (status != 0); |
| handled = 1; |
| } |
| |
| spin_unlock_irqrestore(&uap->port.lock, flags); |
| |
| return IRQ_RETVAL(handled); |
| } |
| |
| static unsigned int pl01x_tx_empty(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned int status = readw(uap->port.membase + UART01x_FR); |
| return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT; |
| } |
| |
| static unsigned int pl01x_get_mctrl(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned int result = 0; |
| unsigned int status = readw(uap->port.membase + UART01x_FR); |
| |
| #define TIOCMBIT(uartbit, tiocmbit) \ |
| if (status & uartbit) \ |
| result |= tiocmbit |
| |
| TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR); |
| TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR); |
| TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS); |
| TIOCMBIT(UART011_FR_RI, TIOCM_RNG); |
| #undef TIOCMBIT |
| return result; |
| } |
| |
| static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned int cr; |
| |
| cr = readw(uap->port.membase + UART011_CR); |
| |
| #define TIOCMBIT(tiocmbit, uartbit) \ |
| if (mctrl & tiocmbit) \ |
| cr |= uartbit; \ |
| else \ |
| cr &= ~uartbit |
| |
| TIOCMBIT(TIOCM_RTS, UART011_CR_RTS); |
| TIOCMBIT(TIOCM_DTR, UART011_CR_DTR); |
| TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1); |
| TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2); |
| TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE); |
| |
| if (uap->autorts) { |
| /* We need to disable auto-RTS if we want to turn RTS off */ |
| TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN); |
| } |
| #undef TIOCMBIT |
| |
| writew(cr, uap->port.membase + UART011_CR); |
| } |
| |
| static void pl011_break_ctl(struct uart_port *port, int break_state) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned long flags; |
| unsigned int lcr_h; |
| |
| spin_lock_irqsave(&uap->port.lock, flags); |
| lcr_h = readw(uap->port.membase + uap->lcrh_tx); |
| if (break_state == -1) |
| lcr_h |= UART01x_LCRH_BRK; |
| else |
| lcr_h &= ~UART01x_LCRH_BRK; |
| writew(lcr_h, uap->port.membase + uap->lcrh_tx); |
| spin_unlock_irqrestore(&uap->port.lock, flags); |
| } |
| |
| #ifdef CONFIG_CONSOLE_POLL |
| static int pl010_get_poll_char(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned int status; |
| |
| status = readw(uap->port.membase + UART01x_FR); |
| if (status & UART01x_FR_RXFE) |
| return NO_POLL_CHAR; |
| |
| return readw(uap->port.membase + UART01x_DR); |
| } |
| |
| static void pl010_put_poll_char(struct uart_port *port, |
| unsigned char ch) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) |
| barrier(); |
| |
| writew(ch, uap->port.membase + UART01x_DR); |
| } |
| |
| #endif /* CONFIG_CONSOLE_POLL */ |
| |
| static int pl011_startup(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned int cr; |
| int retval; |
| |
| retval = clk_prepare(uap->clk); |
| if (retval) |
| goto out; |
| |
| /* |
| * Try to enable the clock producer. |
| */ |
| retval = clk_enable(uap->clk); |
| if (retval) |
| goto clk_unprep; |
| |
| uap->port.uartclk = clk_get_rate(uap->clk); |
| |
| /* |
| * Allocate the IRQ |
| */ |
| retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap); |
| if (retval) |
| goto clk_dis; |
| |
| writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS); |
| |
| /* |
| * Provoke TX FIFO interrupt into asserting. |
| */ |
| cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE; |
| writew(cr, uap->port.membase + UART011_CR); |
| writew(0, uap->port.membase + UART011_FBRD); |
| writew(1, uap->port.membase + UART011_IBRD); |
| writew(0, uap->port.membase + uap->lcrh_rx); |
| if (uap->lcrh_tx != uap->lcrh_rx) { |
| int i; |
| /* |
| * Wait 10 PCLKs before writing LCRH_TX register, |
| * to get this delay write read only register 10 times |
| */ |
| for (i = 0; i < 10; ++i) |
| writew(0xff, uap->port.membase + UART011_MIS); |
| writew(0, uap->port.membase + uap->lcrh_tx); |
| } |
| writew(0, uap->port.membase + UART01x_DR); |
| while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY) |
| barrier(); |
| |
| cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE; |
| writew(cr, uap->port.membase + UART011_CR); |
| |
| /* Clear pending error interrupts */ |
| writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS, |
| uap->port.membase + UART011_ICR); |
| |
| /* |
| * initialise the old status of the modem signals |
| */ |
| uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY; |
| |
| /* Startup DMA */ |
| pl011_dma_startup(uap); |
| |
| /* |
| * Finally, enable interrupts, only timeouts when using DMA |
| * if initial RX DMA job failed, start in interrupt mode |
| * as well. |
| */ |
| spin_lock_irq(&uap->port.lock); |
| uap->im = UART011_RTIM; |
| if (!pl011_dma_rx_running(uap)) |
| uap->im |= UART011_RXIM; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| spin_unlock_irq(&uap->port.lock); |
| |
| if (uap->port.dev->platform_data) { |
| struct amba_pl011_data *plat; |
| |
| plat = uap->port.dev->platform_data; |
| if (plat->init) |
| plat->init(); |
| } |
| |
| return 0; |
| |
| clk_dis: |
| clk_disable(uap->clk); |
| clk_unprep: |
| clk_unprepare(uap->clk); |
| out: |
| return retval; |
| } |
| |
| static void pl011_shutdown_channel(struct uart_amba_port *uap, |
| unsigned int lcrh) |
| { |
| unsigned long val; |
| |
| val = readw(uap->port.membase + lcrh); |
| val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN); |
| writew(val, uap->port.membase + lcrh); |
| } |
| |
| static void pl011_shutdown(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| /* |
| * disable all interrupts |
| */ |
| spin_lock_irq(&uap->port.lock); |
| uap->im = 0; |
| writew(uap->im, uap->port.membase + UART011_IMSC); |
| writew(0xffff, uap->port.membase + UART011_ICR); |
| spin_unlock_irq(&uap->port.lock); |
| |
| pl011_dma_shutdown(uap); |
| |
| /* |
| * Free the interrupt |
| */ |
| free_irq(uap->port.irq, uap); |
| |
| /* |
| * disable the port |
| */ |
| uap->autorts = false; |
| writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR); |
| |
| /* |
| * disable break condition and fifos |
| */ |
| pl011_shutdown_channel(uap, uap->lcrh_rx); |
| if (uap->lcrh_rx != uap->lcrh_tx) |
| pl011_shutdown_channel(uap, uap->lcrh_tx); |
| |
| /* |
| * Shut down the clock producer |
| */ |
| clk_disable(uap->clk); |
| clk_unprepare(uap->clk); |
| |
| if (uap->port.dev->platform_data) { |
| struct amba_pl011_data *plat; |
| |
| plat = uap->port.dev->platform_data; |
| if (plat->exit) |
| plat->exit(); |
| } |
| |
| } |
| |
| static void |
| pl011_set_termios(struct uart_port *port, struct ktermios *termios, |
| struct ktermios *old) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| unsigned int lcr_h, old_cr; |
| unsigned long flags; |
| unsigned int baud, quot, clkdiv; |
| |
| if (uap->vendor->oversampling) |
| clkdiv = 8; |
| else |
| clkdiv = 16; |
| |
| /* |
| * Ask the core to calculate the divisor for us. |
| */ |
| baud = uart_get_baud_rate(port, termios, old, 0, |
| port->uartclk / clkdiv); |
| |
| if (baud > port->uartclk/16) |
| quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud); |
| else |
| quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud); |
| |
| switch (termios->c_cflag & CSIZE) { |
| case CS5: |
| lcr_h = UART01x_LCRH_WLEN_5; |
| break; |
| case CS6: |
| lcr_h = UART01x_LCRH_WLEN_6; |
| break; |
| case CS7: |
| lcr_h = UART01x_LCRH_WLEN_7; |
| break; |
| default: // CS8 |
| lcr_h = UART01x_LCRH_WLEN_8; |
| break; |
| } |
| if (termios->c_cflag & CSTOPB) |
| lcr_h |= UART01x_LCRH_STP2; |
| if (termios->c_cflag & PARENB) { |
| lcr_h |= UART01x_LCRH_PEN; |
| if (!(termios->c_cflag & PARODD)) |
| lcr_h |= UART01x_LCRH_EPS; |
| } |
| if (uap->fifosize > 1) |
| lcr_h |= UART01x_LCRH_FEN; |
| |
| spin_lock_irqsave(&port->lock, flags); |
| |
| /* |
| * Update the per-port timeout. |
| */ |
| uart_update_timeout(port, termios->c_cflag, baud); |
| |
| port->read_status_mask = UART011_DR_OE | 255; |
| if (termios->c_iflag & INPCK) |
| port->read_status_mask |= UART011_DR_FE | UART011_DR_PE; |
| if (termios->c_iflag & (BRKINT | PARMRK)) |
| port->read_status_mask |= UART011_DR_BE; |
| |
| /* |
| * Characters to ignore |
| */ |
| port->ignore_status_mask = 0; |
| if (termios->c_iflag & IGNPAR) |
| port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE; |
| if (termios->c_iflag & IGNBRK) { |
| port->ignore_status_mask |= UART011_DR_BE; |
| /* |
| * If we're ignoring parity and break indicators, |
| * ignore overruns too (for real raw support). |
| */ |
| if (termios->c_iflag & IGNPAR) |
| port->ignore_status_mask |= UART011_DR_OE; |
| } |
| |
| /* |
| * Ignore all characters if CREAD is not set. |
| */ |
| if ((termios->c_cflag & CREAD) == 0) |
| port->ignore_status_mask |= UART_DUMMY_DR_RX; |
| |
| if (UART_ENABLE_MS(port, termios->c_cflag)) |
| pl011_enable_ms(port); |
| |
| /* first, disable everything */ |
| old_cr = readw(port->membase + UART011_CR); |
| writew(0, port->membase + UART011_CR); |
| |
| if (termios->c_cflag & CRTSCTS) { |
| if (old_cr & UART011_CR_RTS) |
| old_cr |= UART011_CR_RTSEN; |
| |
| old_cr |= UART011_CR_CTSEN; |
| uap->autorts = true; |
| } else { |
| old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN); |
| uap->autorts = false; |
| } |
| |
| if (uap->vendor->oversampling) { |
| if (baud > port->uartclk / 16) |
| old_cr |= ST_UART011_CR_OVSFACT; |
| else |
| old_cr &= ~ST_UART011_CR_OVSFACT; |
| } |
| |
| /* Set baud rate */ |
| writew(quot & 0x3f, port->membase + UART011_FBRD); |
| writew(quot >> 6, port->membase + UART011_IBRD); |
| |
| /* |
| * ----------v----------v----------v----------v----- |
| * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L |
| * ----------^----------^----------^----------^----- |
| */ |
| writew(lcr_h, port->membase + uap->lcrh_rx); |
| if (uap->lcrh_rx != uap->lcrh_tx) { |
| int i; |
| /* |
| * Wait 10 PCLKs before writing LCRH_TX register, |
| * to get this delay write read only register 10 times |
| */ |
| for (i = 0; i < 10; ++i) |
| writew(0xff, uap->port.membase + UART011_MIS); |
| writew(lcr_h, port->membase + uap->lcrh_tx); |
| } |
| writew(old_cr, port->membase + UART011_CR); |
| |
| spin_unlock_irqrestore(&port->lock, flags); |
| } |
| |
| static const char *pl011_type(struct uart_port *port) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| return uap->port.type == PORT_AMBA ? uap->type : NULL; |
| } |
| |
| /* |
| * Release the memory region(s) being used by 'port' |
| */ |
| static void pl010_release_port(struct uart_port *port) |
| { |
| release_mem_region(port->mapbase, SZ_4K); |
| } |
| |
| /* |
| * Request the memory region(s) being used by 'port' |
| */ |
| static int pl010_request_port(struct uart_port *port) |
| { |
| return request_mem_region(port->mapbase, SZ_4K, "uart-pl011") |
| != NULL ? 0 : -EBUSY; |
| } |
| |
| /* |
| * Configure/autoconfigure the port. |
| */ |
| static void pl010_config_port(struct uart_port *port, int flags) |
| { |
| if (flags & UART_CONFIG_TYPE) { |
| port->type = PORT_AMBA; |
| pl010_request_port(port); |
| } |
| } |
| |
| /* |
| * verify the new serial_struct (for TIOCSSERIAL). |
| */ |
| static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser) |
| { |
| int ret = 0; |
| if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA) |
| ret = -EINVAL; |
| if (ser->irq < 0 || ser->irq >= nr_irqs) |
| ret = -EINVAL; |
| if (ser->baud_base < 9600) |
| ret = -EINVAL; |
| return ret; |
| } |
| |
| static struct uart_ops amba_pl011_pops = { |
| .tx_empty = pl01x_tx_empty, |
| .set_mctrl = pl011_set_mctrl, |
| .get_mctrl = pl01x_get_mctrl, |
| .stop_tx = pl011_stop_tx, |
| .start_tx = pl011_start_tx, |
| .stop_rx = pl011_stop_rx, |
| .enable_ms = pl011_enable_ms, |
| .break_ctl = pl011_break_ctl, |
| .startup = pl011_startup, |
| .shutdown = pl011_shutdown, |
| .flush_buffer = pl011_dma_flush_buffer, |
| .set_termios = pl011_set_termios, |
| .type = pl011_type, |
| .release_port = pl010_release_port, |
| .request_port = pl010_request_port, |
| .config_port = pl010_config_port, |
| .verify_port = pl010_verify_port, |
| #ifdef CONFIG_CONSOLE_POLL |
| .poll_get_char = pl010_get_poll_char, |
| .poll_put_char = pl010_put_poll_char, |
| #endif |
| }; |
| |
| static struct uart_amba_port *amba_ports[UART_NR]; |
| |
| #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE |
| |
| static void pl011_console_putchar(struct uart_port *port, int ch) |
| { |
| struct uart_amba_port *uap = (struct uart_amba_port *)port; |
| |
| while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) |
| barrier(); |
| writew(ch, uap->port.membase + UART01x_DR); |
| } |
| |
| static void |
| pl011_console_write(struct console *co, const char *s, unsigned int count) |
| { |
| struct uart_amba_port *uap = amba_ports[co->index]; |
| unsigned int status, old_cr, new_cr; |
| |
| clk_enable(uap->clk); |
| |
| /* |
| * First save the CR then disable the interrupts |
| */ |
| old_cr = readw(uap->port.membase + UART011_CR); |
| new_cr = old_cr & ~UART011_CR_CTSEN; |
| new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; |
| writew(new_cr, uap->port.membase + UART011_CR); |
| |
| uart_console_write(&uap->port, s, count, pl011_console_putchar); |
| |
| /* |
| * Finally, wait for transmitter to become empty |
| * and restore the TCR |
| */ |
| do { |
| status = readw(uap->port.membase + UART01x_FR); |
| } while (status & UART01x_FR_BUSY); |
| writew(old_cr, uap->port.membase + UART011_CR); |
| |
| clk_disable(uap->clk); |
| } |
| |
| static void __init |
| pl011_console_get_options(struct uart_amba_port *uap, int *baud, |
| int *parity, int *bits) |
| { |
| if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) { |
| unsigned int lcr_h, ibrd, fbrd; |
| |
| lcr_h = readw(uap->port.membase + uap->lcrh_tx); |
| |
| *parity = 'n'; |
| if (lcr_h & UART01x_LCRH_PEN) { |
| if (lcr_h & UART01x_LCRH_EPS) |
| *parity = 'e'; |
| else |
| *parity = 'o'; |
| } |
| |
| if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7) |
| *bits = 7; |
| else |
| *bits = 8; |
| |
| ibrd = readw(uap->port.membase + UART011_IBRD); |
| fbrd = readw(uap->port.membase + UART011_FBRD); |
| |
| *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd); |
| |
| if (uap->vendor->oversampling) { |
| if (readw(uap->port.membase + UART011_CR) |
| & ST_UART011_CR_OVSFACT) |
| *baud *= 2; |
| } |
| } |
| } |
| |
| static int __init pl011_console_setup(struct console *co, char *options) |
| { |
| struct uart_amba_port *uap; |
| int baud = 38400; |
| int bits = 8; |
| int parity = 'n'; |
| int flow = 'n'; |
| int ret; |
| |
| /* |
| * Check whether an invalid uart number has been specified, and |
| * if so, search for the first available port that does have |
| * console support. |
| */ |
| if (co->index >= UART_NR) |
| co->index = 0; |
| uap = amba_ports[co->index]; |
| if (!uap) |
| return -ENODEV; |
| |
| ret = clk_prepare(uap->clk); |
| if (ret) |
| return ret; |
| |
| if (uap->port.dev->platform_data) { |
| struct amba_pl011_data *plat; |
| |
| plat = uap->port.dev->platform_data; |
| if (plat->init) |
| plat->init(); |
| } |
| |
| uap->port.uartclk = clk_get_rate(uap->clk); |
| |
| if (options) |
| uart_parse_options(options, &baud, &parity, &bits, &flow); |
| else |
| pl011_console_get_options(uap, &baud, &parity, &bits); |
| |
| return uart_set_options(&uap->port, co, baud, parity, bits, flow); |
| } |
| |
| static struct uart_driver amba_reg; |
| static struct console amba_console = { |
| .name = "ttyAMA", |
| .write = pl011_console_write, |
| .device = uart_console_device, |
| .setup = pl011_console_setup, |
| .flags = CON_PRINTBUFFER, |
| .index = -1, |
| .data = &amba_reg, |
| }; |
| |
| #define AMBA_CONSOLE (&amba_console) |
| #else |
| #define AMBA_CONSOLE NULL |
| #endif |
| |
| static struct uart_driver amba_reg = { |
| .owner = THIS_MODULE, |
| .driver_name = "ttyAMA", |
| .dev_name = "ttyAMA", |
| .major = SERIAL_AMBA_MAJOR, |
| .minor = SERIAL_AMBA_MINOR, |
| .nr = UART_NR, |
| .cons = AMBA_CONSOLE, |
| }; |
| |
| static int pl011_probe(struct amba_device *dev, const struct amba_id *id) |
| { |
| struct uart_amba_port *uap; |
| struct vendor_data *vendor = id->data; |
| void __iomem *base; |
| int i, ret; |
| |
| for (i = 0; i < ARRAY_SIZE(amba_ports); i++) |
| if (amba_ports[i] == NULL) |
| break; |
| |
| if (i == ARRAY_SIZE(amba_ports)) { |
| ret = -EBUSY; |
| goto out; |
| } |
| |
| uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL); |
| if (uap == NULL) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| base = ioremap(dev->res.start, resource_size(&dev->res)); |
| if (!base) { |
| ret = -ENOMEM; |
| goto free; |
| } |
| |
| uap->clk = clk_get(&dev->dev, NULL); |
| if (IS_ERR(uap->clk)) { |
| ret = PTR_ERR(uap->clk); |
| goto unmap; |
| } |
| |
| uap->vendor = vendor; |
| uap->lcrh_rx = vendor->lcrh_rx; |
| uap->lcrh_tx = vendor->lcrh_tx; |
| uap->fifosize = vendor->fifosize; |
| uap->interrupt_may_hang = vendor->interrupt_may_hang; |
| uap->port.dev = &dev->dev; |
| uap->port.mapbase = dev->res.start; |
| uap->port.membase = base; |
| uap->port.iotype = UPIO_MEM; |
| uap->port.irq = dev->irq[0]; |
| uap->port.fifosize = uap->fifosize; |
| uap->port.ops = &amba_pl011_pops; |
| uap->port.flags = UPF_BOOT_AUTOCONF; |
| uap->port.line = i; |
| pl011_dma_probe(uap); |
| |
| snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev)); |
| |
| amba_ports[i] = uap; |
| |
| amba_set_drvdata(dev, uap); |
| ret = uart_add_one_port(&amba_reg, &uap->port); |
| if (ret) { |
| amba_set_drvdata(dev, NULL); |
| amba_ports[i] = NULL; |
| pl011_dma_remove(uap); |
| clk_put(uap->clk); |
| unmap: |
| iounmap(base); |
| free: |
| kfree(uap); |
| } |
| out: |
| return ret; |
| } |
| |
| static int pl011_remove(struct amba_device *dev) |
| { |
| struct uart_amba_port *uap = amba_get_drvdata(dev); |
| int i; |
| |
| amba_set_drvdata(dev, NULL); |
| |
| uart_remove_one_port(&amba_reg, &uap->port); |
| |
| for (i = 0; i < ARRAY_SIZE(amba_ports); i++) |
| if (amba_ports[i] == uap) |
| amba_ports[i] = NULL; |
| |
| pl011_dma_remove(uap); |
| iounmap(uap->port.membase); |
| clk_put(uap->clk); |
| kfree(uap); |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM |
| static int pl011_suspend(struct amba_device *dev, pm_message_t state) |
| { |
| struct uart_amba_port *uap = amba_get_drvdata(dev); |
| |
| if (!uap) |
| return -EINVAL; |
| |
| return uart_suspend_port(&amba_reg, &uap->port); |
| } |
| |
| static int pl011_resume(struct amba_device *dev) |
| { |
| struct uart_amba_port *uap = amba_get_drvdata(dev); |
| |
| if (!uap) |
| return -EINVAL; |
| |
| return uart_resume_port(&amba_reg, &uap->port); |
| } |
| #endif |
| |
| static struct amba_id pl011_ids[] = { |
| { |
| .id = 0x00041011, |
| .mask = 0x000fffff, |
| .data = &vendor_arm, |
| }, |
| { |
| .id = 0x00380802, |
| .mask = 0x00ffffff, |
| .data = &vendor_st, |
| }, |
| { 0, 0 }, |
| }; |
| |
| MODULE_DEVICE_TABLE(amba, pl011_ids); |
| |
| static struct amba_driver pl011_driver = { |
| .drv = { |
| .name = "uart-pl011", |
| }, |
| .id_table = pl011_ids, |
| .probe = pl011_probe, |
| .remove = pl011_remove, |
| #ifdef CONFIG_PM |
| .suspend = pl011_suspend, |
| .resume = pl011_resume, |
| #endif |
| }; |
| |
| static int __init pl011_init(void) |
| { |
| int ret; |
| printk(KERN_INFO "Serial: AMBA PL011 UART driver\n"); |
| |
| ret = uart_register_driver(&amba_reg); |
| if (ret == 0) { |
| ret = amba_driver_register(&pl011_driver); |
| if (ret) |
| uart_unregister_driver(&amba_reg); |
| } |
| return ret; |
| } |
| |
| static void __exit pl011_exit(void) |
| { |
| amba_driver_unregister(&pl011_driver); |
| uart_unregister_driver(&amba_reg); |
| } |
| |
| /* |
| * While this can be a module, if builtin it's most likely the console |
| * So let's leave module_exit but move module_init to an earlier place |
| */ |
| arch_initcall(pl011_init); |
| module_exit(pl011_exit); |
| |
| MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); |
| MODULE_DESCRIPTION("ARM AMBA serial port driver"); |
| MODULE_LICENSE("GPL"); |