Commit 386a4153 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Stefan Richter
Browse files

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: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 78dec56d

drivers/firewire/ohci.c

+4 −4
Original line number Diff line number Diff line
@@ -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;

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