/*
- * Isochronous IO functionality
+ * Isochronous I/O functionality:
+ * - Isochronous DMA context management
+ * - Isochronous bus resource management (channels, bandwidth), client side
*
* Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
*
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
-#include <linux/kernel.h>
-#include <linux/module.h>
#include <linux/dma-mapping.h>
-#include <linux/vmalloc.h>
+#include <linux/errno.h>
+#include <linux/firewire-constants.h>
+#include <linux/kernel.h>
#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
-#include "fw-transaction.h"
#include "fw-topology.h"
-#include "fw-device.h"
+#include "fw-transaction.h"
-int
-fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
- int page_count, enum dma_data_direction direction)
+/*
+ * Isochronous DMA context management
+ */
+
+int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
+ int page_count, enum dma_data_direction direction)
{
- int i, j, retval = -ENOMEM;
+ int i, j;
dma_addr_t address;
buffer->page_count = page_count;
kfree(buffer->pages);
out:
buffer->pages = NULL;
- return retval;
+
+ return -ENOMEM;
}
int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
{
unsigned long uaddr;
- int i, retval;
+ int i, err;
uaddr = vma->vm_start;
for (i = 0; i < buffer->page_count; i++) {
- retval = vm_insert_page(vma, uaddr, buffer->pages[i]);
- if (retval)
- return retval;
+ err = vm_insert_page(vma, uaddr, buffer->pages[i]);
+ if (err)
+ return err;
+
uaddr += PAGE_SIZE;
}
buffer->pages = NULL;
}
-struct fw_iso_context *
-fw_iso_context_create(struct fw_card *card, int type,
- int channel, int speed, size_t header_size,
- fw_iso_callback_t callback, void *callback_data)
+struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
+ int type, int channel, int speed, size_t header_size,
+ fw_iso_callback_t callback, void *callback_data)
{
struct fw_iso_context *ctx;
- ctx = card->driver->allocate_iso_context(card, type, header_size);
+ ctx = card->driver->allocate_iso_context(card,
+ type, channel, header_size);
if (IS_ERR(ctx))
return ctx;
card->driver->free_iso_context(ctx);
}
-int
-fw_iso_context_start(struct fw_iso_context *ctx, int cycle, int sync, int tags)
+int fw_iso_context_start(struct fw_iso_context *ctx,
+ int cycle, int sync, int tags)
{
return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
}
-int
-fw_iso_context_queue(struct fw_iso_context *ctx,
- struct fw_iso_packet *packet,
- struct fw_iso_buffer *buffer,
- unsigned long payload)
+int fw_iso_context_queue(struct fw_iso_context *ctx,
+ struct fw_iso_packet *packet,
+ struct fw_iso_buffer *buffer,
+ unsigned long payload)
{
struct fw_card *card = ctx->card;
return card->driver->queue_iso(ctx, packet, buffer, payload);
}
-int
-fw_iso_context_stop(struct fw_iso_context *ctx)
+int fw_iso_context_stop(struct fw_iso_context *ctx)
{
return ctx->card->driver->stop_iso(ctx);
}
+
+/*
+ * Isochronous bus resource management (channels, bandwidth), client side
+ */
+
+static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
+ int bandwidth, bool allocate)
+{
+ __be32 data[2];
+ int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
+
+ /*
+ * On a 1394a IRM with low contention, try < 1 is enough.
+ * On a 1394-1995 IRM, we need at least try < 2.
+ * Let's just do try < 5.
+ */
+ for (try = 0; try < 5; try++) {
+ new = allocate ? old - bandwidth : old + bandwidth;
+ if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
+ break;
+
+ data[0] = cpu_to_be32(old);
+ data[1] = cpu_to_be32(new);
+ switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
+ irm_id, generation, SCODE_100,
+ CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
+ data, sizeof(data))) {
+ case RCODE_GENERATION:
+ /* A generation change frees all bandwidth. */
+ return allocate ? -EAGAIN : bandwidth;
+
+ case RCODE_COMPLETE:
+ if (be32_to_cpup(data) == old)
+ return bandwidth;
+
+ old = be32_to_cpup(data);
+ /* Fall through. */
+ }
+ }
+
+ return -EIO;
+}
+
+static int manage_channel(struct fw_card *card, int irm_id, int generation,
+ u32 channels_mask, u64 offset, bool allocate)
+{
+ __be32 data[2], c, all, old;
+ int i, retry = 5;
+
+ old = all = allocate ? cpu_to_be32(~0) : 0;
+
+ for (i = 0; i < 32; i++) {
+ if (!(channels_mask & 1 << i))
+ continue;
+
+ c = cpu_to_be32(1 << (31 - i));
+ if ((old & c) != (all & c))
+ continue;
+
+ data[0] = old;
+ data[1] = old ^ c;
+ switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
+ irm_id, generation, SCODE_100,
+ offset, data, sizeof(data))) {
+ case RCODE_GENERATION:
+ /* A generation change frees all channels. */
+ return allocate ? -EAGAIN : i;
+
+ case RCODE_COMPLETE:
+ if (data[0] == old)
+ return i;
+
+ old = data[0];
+
+ /* Is the IRM 1394a-2000 compliant? */
+ if ((data[0] & c) == (data[1] & c))
+ continue;
+
+ /* 1394-1995 IRM, fall through to retry. */
+ default:
+ if (retry--)
+ i--;
+ }
+ }
+
+ return -EIO;
+}
+
+static void deallocate_channel(struct fw_card *card, int irm_id,
+ int generation, int channel)
+{
+ u32 mask;
+ u64 offset;
+
+ mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
+ offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
+ CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
+
+ manage_channel(card, irm_id, generation, mask, offset, false);
+}
+
+/**
+ * fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
+ *
+ * In parameters: card, generation, channels_mask, bandwidth, allocate
+ * Out parameters: channel, bandwidth
+ * This function blocks (sleeps) during communication with the IRM.
+ *
+ * Allocates or deallocates at most one channel out of channels_mask.
+ * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
+ * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
+ * channel 0 and LSB for channel 63.)
+ * Allocates or deallocates as many bandwidth allocation units as specified.
+ *
+ * Returns channel < 0 if no channel was allocated or deallocated.
+ * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
+ *
+ * If generation is stale, deallocations succeed but allocations fail with
+ * channel = -EAGAIN.
+ *
+ * If channel allocation fails, no bandwidth will be allocated either.
+ * If bandwidth allocation fails, no channel will be allocated either.
+ * But deallocations of channel and bandwidth are tried independently
+ * of each other's success.
+ */
+void fw_iso_resource_manage(struct fw_card *card, int generation,
+ u64 channels_mask, int *channel, int *bandwidth,
+ bool allocate)
+{
+ u32 channels_hi = channels_mask; /* channels 31...0 */
+ u32 channels_lo = channels_mask >> 32; /* channels 63...32 */
+ int irm_id, ret, c = -EINVAL;
+
+ spin_lock_irq(&card->lock);
+ irm_id = card->irm_node->node_id;
+ spin_unlock_irq(&card->lock);
+
+ if (channels_hi)
+ c = manage_channel(card, irm_id, generation, channels_hi,
+ CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
+ if (channels_lo && c < 0) {
+ c = manage_channel(card, irm_id, generation, channels_lo,
+ CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
+ if (c >= 0)
+ c += 32;
+ }
+ *channel = c;
+
+ if (allocate && channels_mask != 0 && c < 0)
+ *bandwidth = 0;
+
+ if (*bandwidth == 0)
+ return;
+
+ ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
+ if (ret < 0)
+ *bandwidth = 0;
+
+ if (allocate && ret < 0 && c >= 0) {
+ deallocate_channel(card, irm_id, generation, c);
+ *channel = ret;
+ }
+}
projects / firefly-linux-kernel-4.4.55.git / blobdiff