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firewire: ohci: simplify iso header pointer arithmetic 

When storing the header data of completed iso packets, we effectively
treat the buffers as arrays of quadlets.  Actually declaring the
pointers as u32* avoids repetitive pointer arithmetic, removes the
unhelpfully named "i" variables, and thus makes the code clearer.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Clemens Ladisch 2012-03-18 19:04:05 +01:00 committed by Stefan Richter
parent 90fcc89873
commit 73864012f3
1 changed files with 12 additions and 10 deletions
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22
drivers/firewire/ohci.c
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@ -2676,24 +2676,26 @@ static void ohci_write_csr(struct fw_card *card, int csr_offset, u32 value)
}
}
static void copy_iso_headers(struct iso_context *ctx, void *p)
static void copy_iso_headers(struct iso_context *ctx, const u32 *dma_hdr)
{
int i = ctx->header_length;
u32 *ctx_hdr;
if (i + ctx->base.header_size > PAGE_SIZE)
if (ctx->header_length + ctx->base.header_size > PAGE_SIZE)
return;
ctx_hdr = ctx->header + ctx->header_length;
/*
* The two iso header quadlets are byteswapped to little
* endian by the controller, but we want to present them
* as big endian for consistency with the bus endianness.
*/
if (ctx->base.header_size > 0)
*(u32 *) (ctx->header + i) = __swab32(*(u32 *) (p + 4));
ctx_hdr[0] = swab32(dma_hdr[1]); /* iso packet header */
if (ctx->base.header_size > 4)
*(u32 *) (ctx->header + i + 4) = __swab32(*(u32 *) p);
ctx_hdr[1] = swab32(dma_hdr[0]); /* timestamp */
if (ctx->base.header_size > 8)
memcpy(ctx->header + i + 8, p + 8, ctx->base.header_size - 8);
memcpy(&ctx_hdr[2], &dma_hdr[2], ctx->base.header_size - 8);
ctx->header_length += ctx->base.header_size;
}
@ -2812,8 +2814,8 @@ static int handle_it_packet(struct context *context,
{
struct iso_context *ctx =
container_of(context, struct iso_context, context);
int i;
struct descriptor *pd;
__be32 *ctx_hdr;
for (pd = d; pd <= last; pd++)
if (pd->transfer_status)
@ -2824,10 +2826,10 @@ static int handle_it_packet(struct context *context,
sync_it_packet_for_cpu(context, d);
i = ctx->header_length;
if (i + 4 < PAGE_SIZE) {
if (ctx->header_length + 4 < PAGE_SIZE) {
ctx_hdr = ctx->header + ctx->header_length;
/* Present this value as big-endian to match the receive code */
*(__be32 *)(ctx->header + i) = cpu_to_be32(
*ctx_hdr = cpu_to_be32(
((u32)le16_to_cpu(pd->transfer_status) << 16) |
le16_to_cpu(pd->res_count));
ctx->header_length += 4;