| /* |
| * arch/arm/mach-at91/pm_slow_clock.S |
| * |
| * Copyright (C) 2006 Savin Zlobec |
| * |
| * AT91SAM9 support: |
| * Copyright (C) 2007 Anti Sullin <anti.sullin@artecdesign.ee |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| */ |
| |
| #include <linux/linkage.h> |
| #include <mach/hardware.h> |
| #include <mach/at91_pmc.h> |
| #include <mach/at91_ramc.h> |
| |
| |
| #ifdef CONFIG_ARCH_AT91SAM9263 |
| /* |
| * FIXME either or both the SDRAM controllers (EB0, EB1) might be in use; |
| * handle those cases both here and in the Suspend-To-RAM support. |
| */ |
| #warning Assuming EB1 SDRAM controller is *NOT* used |
| #endif |
| |
| /* |
| * When SLOWDOWN_MASTER_CLOCK is defined we will also slow down the Master |
| * clock during suspend by adjusting its prescalar and divisor. |
| * NOTE: This hasn't been shown to be stable on SAM9s; and on the RM9200 there |
| * are errata regarding adjusting the prescalar and divisor. |
| */ |
| #undef SLOWDOWN_MASTER_CLOCK |
| |
| #define MCKRDY_TIMEOUT 1000 |
| #define MOSCRDY_TIMEOUT 1000 |
| #define PLLALOCK_TIMEOUT 1000 |
| #define PLLBLOCK_TIMEOUT 1000 |
| |
| pmc .req r0 |
| sdramc .req r1 |
| ramc1 .req r2 |
| tmp1 .req r3 |
| tmp2 .req r4 |
| |
| /* |
| * Wait until master clock is ready (after switching master clock source) |
| */ |
| .macro wait_mckrdy |
| mov tmp2, #MCKRDY_TIMEOUT |
| 1: sub tmp2, tmp2, #1 |
| cmp tmp2, #0 |
| beq 2f |
| ldr tmp1, [pmc, #(AT91_PMC_SR - AT91_PMC)] |
| tst tmp1, #AT91_PMC_MCKRDY |
| beq 1b |
| 2: |
| .endm |
| |
| /* |
| * Wait until master oscillator has stabilized. |
| */ |
| .macro wait_moscrdy |
| mov tmp2, #MOSCRDY_TIMEOUT |
| 1: sub tmp2, tmp2, #1 |
| cmp tmp2, #0 |
| beq 2f |
| ldr tmp1, [pmc, #(AT91_PMC_SR - AT91_PMC)] |
| tst tmp1, #AT91_PMC_MOSCS |
| beq 1b |
| 2: |
| .endm |
| |
| /* |
| * Wait until PLLA has locked. |
| */ |
| .macro wait_pllalock |
| mov tmp2, #PLLALOCK_TIMEOUT |
| 1: sub tmp2, tmp2, #1 |
| cmp tmp2, #0 |
| beq 2f |
| ldr tmp1, [pmc, #(AT91_PMC_SR - AT91_PMC)] |
| tst tmp1, #AT91_PMC_LOCKA |
| beq 1b |
| 2: |
| .endm |
| |
| /* |
| * Wait until PLLB has locked. |
| */ |
| .macro wait_pllblock |
| mov tmp2, #PLLBLOCK_TIMEOUT |
| 1: sub tmp2, tmp2, #1 |
| cmp tmp2, #0 |
| beq 2f |
| ldr tmp1, [pmc, #(AT91_PMC_SR - AT91_PMC)] |
| tst tmp1, #AT91_PMC_LOCKB |
| beq 1b |
| 2: |
| .endm |
| |
| .text |
| |
| /* void at91_slow_clock(void __iomem *pmc, void __iomem *sdramc, void __iomem *ramc1) */ |
| ENTRY(at91_slow_clock) |
| /* Save registers on stack */ |
| stmfd sp!, {r3 - r12, lr} |
| |
| /* |
| * Register usage: |
| * R0 = Base address of AT91_PMC |
| * R1 = Base address of RAM Controller (SDRAM, DDRSDR, or AT91_SYS) |
| * R2 = Base address of second RAM Controller or 0 if not present |
| * R3 = temporary register |
| * R4 = temporary register |
| */ |
| |
| /* Drain write buffer */ |
| mov tmp1, #0 |
| mcr p15, 0, tmp1, c7, c10, 4 |
| |
| #ifdef CONFIG_ARCH_AT91RM9200 |
| /* Put SDRAM in self-refresh mode */ |
| mov tmp1, #1 |
| str tmp1, [sdramc, #AT91RM9200_SDRAMC_SRR] |
| #elif defined(CONFIG_ARCH_AT91SAM9G45) |
| |
| /* prepare for DDRAM self-refresh mode */ |
| ldr tmp1, [sdramc, #AT91_DDRSDRC_LPR] |
| str tmp1, .saved_sam9_lpr |
| bic tmp1, #AT91_DDRSDRC_LPCB |
| orr tmp1, #AT91_DDRSDRC_LPCB_SELF_REFRESH |
| |
| /* figure out if we use the second ram controller */ |
| cmp ramc1, #0 |
| ldrne tmp2, [ramc1, #AT91_DDRSDRC_LPR] |
| strne tmp2, .saved_sam9_lpr1 |
| bicne tmp2, #AT91_DDRSDRC_LPCB |
| orrne tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH |
| |
| /* Enable DDRAM self-refresh mode */ |
| str tmp1, [sdramc, #AT91_DDRSDRC_LPR] |
| strne tmp2, [ramc1, #AT91_DDRSDRC_LPR] |
| #else |
| /* Enable SDRAM self-refresh mode */ |
| ldr tmp1, [sdramc, #AT91_SDRAMC_LPR] |
| str tmp1, .saved_sam9_lpr |
| |
| bic tmp1, #AT91_SDRAMC_LPCB |
| orr tmp1, #AT91_SDRAMC_LPCB_SELF_REFRESH |
| str tmp1, [sdramc, #AT91_SDRAMC_LPR] |
| #endif |
| |
| /* Save Master clock setting */ |
| ldr tmp1, [pmc, #(AT91_PMC_MCKR - AT91_PMC)] |
| str tmp1, .saved_mckr |
| |
| /* |
| * Set the Master clock source to slow clock |
| */ |
| bic tmp1, tmp1, #AT91_PMC_CSS |
| str tmp1, [pmc, #(AT91_PMC_MCKR - AT91_PMC)] |
| |
| wait_mckrdy |
| |
| #ifdef SLOWDOWN_MASTER_CLOCK |
| /* |
| * Set the Master Clock PRES and MDIV fields. |
| * |
| * See AT91RM9200 errata #27 and #28 for details. |
| */ |
| mov tmp1, #0 |
| str tmp1, [pmc, #(AT91_PMC_MCKR - AT91_PMC)] |
| |
| wait_mckrdy |
| #endif |
| |
| /* Save PLLA setting and disable it */ |
| ldr tmp1, [pmc, #(AT91_CKGR_PLLAR - AT91_PMC)] |
| str tmp1, .saved_pllar |
| |
| mov tmp1, #AT91_PMC_PLLCOUNT |
| orr tmp1, tmp1, #(1 << 29) /* bit 29 always set */ |
| str tmp1, [pmc, #(AT91_CKGR_PLLAR - AT91_PMC)] |
| |
| /* Save PLLB setting and disable it */ |
| ldr tmp1, [pmc, #(AT91_CKGR_PLLBR - AT91_PMC)] |
| str tmp1, .saved_pllbr |
| |
| mov tmp1, #AT91_PMC_PLLCOUNT |
| str tmp1, [pmc, #(AT91_CKGR_PLLBR - AT91_PMC)] |
| |
| /* Turn off the main oscillator */ |
| ldr tmp1, [pmc, #(AT91_CKGR_MOR - AT91_PMC)] |
| bic tmp1, tmp1, #AT91_PMC_MOSCEN |
| str tmp1, [pmc, #(AT91_CKGR_MOR - AT91_PMC)] |
| |
| /* Wait for interrupt */ |
| mcr p15, 0, tmp1, c7, c0, 4 |
| |
| /* Turn on the main oscillator */ |
| ldr tmp1, [pmc, #(AT91_CKGR_MOR - AT91_PMC)] |
| orr tmp1, tmp1, #AT91_PMC_MOSCEN |
| str tmp1, [pmc, #(AT91_CKGR_MOR - AT91_PMC)] |
| |
| wait_moscrdy |
| |
| /* Restore PLLB setting */ |
| ldr tmp1, .saved_pllbr |
| str tmp1, [pmc, #(AT91_CKGR_PLLBR - AT91_PMC)] |
| |
| tst tmp1, #(AT91_PMC_MUL & 0xff0000) |
| bne 1f |
| tst tmp1, #(AT91_PMC_MUL & ~0xff0000) |
| beq 2f |
| 1: |
| wait_pllblock |
| 2: |
| |
| /* Restore PLLA setting */ |
| ldr tmp1, .saved_pllar |
| str tmp1, [pmc, #(AT91_CKGR_PLLAR - AT91_PMC)] |
| |
| tst tmp1, #(AT91_PMC_MUL & 0xff0000) |
| bne 3f |
| tst tmp1, #(AT91_PMC_MUL & ~0xff0000) |
| beq 4f |
| 3: |
| wait_pllalock |
| 4: |
| |
| #ifdef SLOWDOWN_MASTER_CLOCK |
| /* |
| * First set PRES if it was not 0, |
| * than set CSS and MDIV fields. |
| * |
| * See AT91RM9200 errata #27 and #28 for details. |
| */ |
| ldr tmp1, .saved_mckr |
| tst tmp1, #AT91_PMC_PRES |
| beq 2f |
| and tmp1, tmp1, #AT91_PMC_PRES |
| str tmp1, [pmc, #(AT91_PMC_MCKR - AT91_PMC)] |
| |
| wait_mckrdy |
| #endif |
| |
| /* |
| * Restore master clock setting |
| */ |
| 2: ldr tmp1, .saved_mckr |
| str tmp1, [pmc, #(AT91_PMC_MCKR - AT91_PMC)] |
| |
| wait_mckrdy |
| |
| #ifdef CONFIG_ARCH_AT91RM9200 |
| /* Do nothing - self-refresh is automatically disabled. */ |
| #elif defined(CONFIG_ARCH_AT91SAM9G45) |
| /* Restore LPR on AT91 with DDRAM */ |
| ldr tmp1, .saved_sam9_lpr |
| str tmp1, [sdramc, #AT91_DDRSDRC_LPR] |
| |
| /* if we use the second ram controller */ |
| cmp ramc1, #0 |
| ldrne tmp2, .saved_sam9_lpr1 |
| strne tmp2, [ramc1, #AT91_DDRSDRC_LPR] |
| |
| #else |
| /* Restore LPR on AT91 with SDRAM */ |
| ldr tmp1, .saved_sam9_lpr |
| str tmp1, [sdramc, #AT91_SDRAMC_LPR] |
| #endif |
| |
| /* Restore registers, and return */ |
| ldmfd sp!, {r3 - r12, pc} |
| |
| |
| .saved_mckr: |
| .word 0 |
| |
| .saved_pllar: |
| .word 0 |
| |
| .saved_pllbr: |
| .word 0 |
| |
| .saved_sam9_lpr: |
| .word 0 |
| |
| .saved_sam9_lpr1: |
| .word 0 |
| |
| ENTRY(at91_slow_clock_sz) |
| .word .-at91_slow_clock |