firewire: add isochronous multichannel reception
This adds the DMA context programming and userspace ABI for multichannel
reception, i.e. for listening on multiple channel numbers by means of a
single DMA context.
The use case is reception of more streams than there are IR DMA units
offered by the link layer. This is already implemented by the older
ohci1394 + ieee1394 + raw1394 stack. And as discussed recently on
linux1394-devel, this feature is occasionally used in practice.
The big drawbacks of this mode are that buffer layout and interrupt
generation necessarily differ from single-channel reception: Headers
and trailers are not stripped from packets, packets are not aligned with
buffer chunks, interrupts are per buffer chunk, not per packet.
These drawbacks also cause a rather hefty code footprint to support this
rarely used OHCI-1394 feature. (367 lines added, among them 94 lines of
added userspace ABI documentation.)
This implementation enforces that a multichannel reception context may
only listen to channels to which no single-channel context on the same
link layer is presently listening to. OHCI-1394 would allow to overlay
single-channel contexts by the multi-channel context, but this would be
a departure from the present first-come-first-served policy of IR
context creation.
The implementation is heavily based on an earlier one by Jay Fenlason.
Thanks Jay.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index cf989e1..ba23646 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -193,6 +193,11 @@
struct fw_cdev_event_iso_interrupt interrupt;
};
+struct iso_interrupt_mc_event {
+ struct event event;
+ struct fw_cdev_event_iso_interrupt_mc interrupt;
+};
+
struct iso_resource_event {
struct event event;
struct fw_cdev_event_iso_resource iso_resource;
@@ -415,6 +420,7 @@
struct fw_cdev_get_cycle_timer2 get_cycle_timer2;
struct fw_cdev_send_phy_packet send_phy_packet;
struct fw_cdev_receive_phy_packets receive_phy_packets;
+ struct fw_cdev_set_iso_channels set_iso_channels;
};
static int ioctl_get_info(struct client *client, union ioctl_arg *arg)
@@ -932,26 +938,54 @@
sizeof(e->interrupt) + header_length, NULL, 0);
}
+static void iso_mc_callback(struct fw_iso_context *context,
+ dma_addr_t completed, void *data)
+{
+ struct client *client = data;
+ struct iso_interrupt_mc_event *e;
+
+ e = kmalloc(sizeof(*e), GFP_ATOMIC);
+ if (e == NULL) {
+ fw_notify("Out of memory when allocating event\n");
+ return;
+ }
+ e->interrupt.type = FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL;
+ e->interrupt.closure = client->iso_closure;
+ e->interrupt.completed = fw_iso_buffer_lookup(&client->buffer,
+ completed);
+ queue_event(client, &e->event, &e->interrupt,
+ sizeof(e->interrupt), NULL, 0);
+}
+
static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
{
struct fw_cdev_create_iso_context *a = &arg->create_iso_context;
struct fw_iso_context *context;
+ fw_iso_callback_t cb;
BUILD_BUG_ON(FW_CDEV_ISO_CONTEXT_TRANSMIT != FW_ISO_CONTEXT_TRANSMIT ||
- FW_CDEV_ISO_CONTEXT_RECEIVE != FW_ISO_CONTEXT_RECEIVE);
-
- if (a->channel > 63)
- return -EINVAL;
+ FW_CDEV_ISO_CONTEXT_RECEIVE != FW_ISO_CONTEXT_RECEIVE ||
+ FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL !=
+ FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL);
switch (a->type) {
- case FW_ISO_CONTEXT_RECEIVE:
- if (a->header_size < 4 || (a->header_size & 3))
+ case FW_ISO_CONTEXT_TRANSMIT:
+ if (a->speed > SCODE_3200 || a->channel > 63)
return -EINVAL;
+
+ cb = iso_callback;
break;
- case FW_ISO_CONTEXT_TRANSMIT:
- if (a->speed > SCODE_3200)
+ case FW_ISO_CONTEXT_RECEIVE:
+ if (a->header_size < 4 || (a->header_size & 3) ||
+ a->channel > 63)
return -EINVAL;
+
+ cb = iso_callback;
+ break;
+
+ case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
+ cb = (fw_iso_callback_t)iso_mc_callback;
break;
default:
@@ -959,8 +993,7 @@
}
context = fw_iso_context_create(client->device->card, a->type,
- a->channel, a->speed, a->header_size,
- iso_callback, client);
+ a->channel, a->speed, a->header_size, cb, client);
if (IS_ERR(context))
return PTR_ERR(context);
@@ -980,6 +1013,17 @@
return 0;
}
+static int ioctl_set_iso_channels(struct client *client, union ioctl_arg *arg)
+{
+ struct fw_cdev_set_iso_channels *a = &arg->set_iso_channels;
+ struct fw_iso_context *ctx = client->iso_context;
+
+ if (ctx == NULL || a->handle != 0)
+ return -EINVAL;
+
+ return fw_iso_context_set_channels(ctx, &a->channels);
+}
+
/* Macros for decoding the iso packet control header. */
#define GET_PAYLOAD_LENGTH(v) ((v) & 0xffff)
#define GET_INTERRUPT(v) (((v) >> 16) & 0x01)
@@ -993,7 +1037,7 @@
struct fw_cdev_queue_iso *a = &arg->queue_iso;
struct fw_cdev_iso_packet __user *p, *end, *next;
struct fw_iso_context *ctx = client->iso_context;
- unsigned long payload, buffer_end, transmit_header_bytes;
+ unsigned long payload, buffer_end, transmit_header_bytes = 0;
u32 control;
int count;
struct {
@@ -1013,7 +1057,6 @@
* use the indirect payload, the iso buffer need not be mapped
* and the a->data pointer is ignored.
*/
-
payload = (unsigned long)a->data - client->vm_start;
buffer_end = client->buffer.page_count << PAGE_SHIFT;
if (a->data == 0 || client->buffer.pages == NULL ||
@@ -1022,8 +1065,10 @@
buffer_end = 0;
}
- p = (struct fw_cdev_iso_packet __user *)u64_to_uptr(a->packets);
+ if (ctx->type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL && payload & 3)
+ return -EINVAL;
+ p = (struct fw_cdev_iso_packet __user *)u64_to_uptr(a->packets);
if (!access_ok(VERIFY_READ, p, a->size))
return -EFAULT;
@@ -1039,19 +1084,24 @@
u.packet.sy = GET_SY(control);
u.packet.header_length = GET_HEADER_LENGTH(control);
- if (ctx->type == FW_ISO_CONTEXT_TRANSMIT) {
- if (u.packet.header_length % 4 != 0)
+ switch (ctx->type) {
+ case FW_ISO_CONTEXT_TRANSMIT:
+ if (u.packet.header_length & 3)
return -EINVAL;
transmit_header_bytes = u.packet.header_length;
- } else {
- /*
- * We require that header_length is a multiple of
- * the fixed header size, ctx->header_size.
- */
+ break;
+
+ case FW_ISO_CONTEXT_RECEIVE:
if (u.packet.header_length == 0 ||
u.packet.header_length % ctx->header_size != 0)
return -EINVAL;
- transmit_header_bytes = 0;
+ break;
+
+ case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
+ if (u.packet.payload_length == 0 ||
+ u.packet.payload_length & 3)
+ return -EINVAL;
+ break;
}
next = (struct fw_cdev_iso_packet __user *)
@@ -1534,6 +1584,7 @@
[0x14] = ioctl_get_cycle_timer2,
[0x15] = ioctl_send_phy_packet,
[0x16] = ioctl_receive_phy_packets,
+ [0x17] = ioctl_set_iso_channels,
};
static int dispatch_ioctl(struct client *client,