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authorClemens Ladisch <clemens@ladisch.de>2010-12-24 14:42:46 +0100
committerStefan Richter <stefanr@s5r6.in-berlin.de>2011-01-04 08:48:33 +0100
commit386a4153a2c1455e424f280d636efa3c91864466 (patch)
treeb99bc0351da1d37808d633cb8d64c1030dc37479
parent78dec56d6a56322e1b728d51f3a7def416d36b34 (diff)
downloadlinux-386a4153a2c1455e424f280d636efa3c91864466.tar.bz2
firewire: ohci: cache the context run bit
The DMA context run control bit is entirely controlled by software, so it is safe to cache it. This allows the driver to avoid doing an additional MMIO read when queueing an AT packet. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
-rw-r--r--drivers/firewire/ohci.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index cfe5afe359c6..3ae84e2c5192 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -125,6 +125,7 @@ struct context {
struct fw_ohci *ohci;
u32 regs;
int total_allocation;
+ bool running;
bool flushing;
/*
@@ -1174,6 +1175,7 @@ static void context_run(struct context *ctx, u32 extra)
le32_to_cpu(ctx->last->branch_address));
reg_write(ohci, CONTROL_CLEAR(ctx->regs), ~0);
reg_write(ohci, CONTROL_SET(ctx->regs), CONTEXT_RUN | extra);
+ ctx->running = true;
flush_writes(ohci);
}
@@ -1202,6 +1204,7 @@ static void context_stop(struct context *ctx)
ctx->active = false;
reg_write(ctx->ohci, CONTROL_CLEAR(ctx->regs), CONTEXT_RUN);
+ ctx->running = false;
flush_writes(ctx->ohci);
for (i = 0; i < 10; i++) {
@@ -1232,7 +1235,6 @@ static int at_context_queue_packet(struct context *ctx,
struct descriptor *d, *last;
__le32 *header;
int z, tcode;
- u32 reg;
d = context_get_descriptors(ctx, 4, &d_bus);
if (d == NULL) {
@@ -1351,9 +1353,7 @@ static int at_context_queue_packet(struct context *ctx,
context_append(ctx, d, z, 4 - z);
- /* If the context isn't already running, start it up. */
- reg = reg_read(ctx->ohci, CONTROL_SET(ctx->regs));
- if ((reg & CONTEXT_RUN) == 0)
+ if (!ctx->running)
context_run(ctx, 0);
return 0;