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spi: axi-spi-engine: remove use of ida for sync id

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Profiling has shown that ida_alloc_range() accounts for about 10% of the
time spent in spi_sync() when using the AXI SPI Engine controller. This
call is used to create a unique id for each SPI message to match to an
IRQ when the message is complete.

Since the core SPI code serializes messages in a message queue, we can
only have one message in flight at a time, namely host->cur_msg. This
means that we can use a fixed value instead of a unique id for each
message since there can never be more than one message pending at a
time.

This patch removes the use of ida for the sync id and replaces it with a
constant value. This simplifies the driver and improves performance.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240207-axi-spi-engine-round-2-1-v2-1-40c0b4e85352@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
David Lechner 2024-02-07 08:51:24 -06:00 committed by Mark Brown
parent c0c0293cf7
commit 531860e12d
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 6 additions and 22 deletions
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28
drivers/spi/spi-axi-spi-engine.c
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@ -7,7 +7,6 @@
#include <linux/clk.h>
#include <linux/fpga/adi-axi-common.h>
#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
@ -57,6 +56,9 @@
#define SPI_ENGINE_TRANSFER_WRITE 0x1
#define SPI_ENGINE_TRANSFER_READ 0x2
/* Arbitrary sync ID for use by host->cur_msg */
#define AXI_SPI_ENGINE_CUR_MSG_SYNC_ID 0x1
#define SPI_ENGINE_CMD(inst, arg1, arg2) \
(((inst) << 12) | ((arg1) << 8) | (arg2))
@ -98,8 +100,6 @@ struct spi_engine_message_state {
unsigned int rx_length;
/** @rx_buf: Bytes not yet written to the RX FIFO. */
uint8_t *rx_buf;
/** @sync_id: ID to correlate SYNC interrupts with this message. */
u8 sync_id;
};
struct spi_engine {
@ -109,7 +109,6 @@ struct spi_engine {
spinlock_t lock;
void __iomem *base;
struct ida sync_ida;
struct timer_list watchdog_timer;
struct spi_controller *controller;
@ -483,9 +482,7 @@ static irqreturn_t spi_engine_irq(int irq, void *devid)
}
if (pending & SPI_ENGINE_INT_SYNC && msg) {
struct spi_engine_message_state *st = msg->state;
if (completed_id == st->sync_id) {
if (completed_id == AXI_SPI_ENGINE_CUR_MSG_SYNC_ID) {
if (timer_delete_sync(&spi_engine->watchdog_timer)) {
msg->status = 0;
msg->actual_length = msg->frame_length;
@ -510,10 +507,8 @@ static int spi_engine_prepare_message(struct spi_controller *host,
struct spi_message *msg)
{
struct spi_engine_program p_dry, *p;
struct spi_engine *spi_engine = spi_controller_get_devdata(host);
struct spi_engine_message_state *st;
size_t size;
int ret;
st = kzalloc(sizeof(*st), GFP_KERNEL);
if (!st)
@ -531,18 +526,10 @@ static int spi_engine_prepare_message(struct spi_controller *host,
return -ENOMEM;
}
ret = ida_alloc_range(&spi_engine->sync_ida, 0, U8_MAX, GFP_KERNEL);
if (ret < 0) {
kfree(p);
kfree(st);
return ret;
}
st->sync_id = ret;
spi_engine_compile_message(msg, false, p);
spi_engine_program_add_cmd(p, false, SPI_ENGINE_CMD_SYNC(st->sync_id));
spi_engine_program_add_cmd(p, false, SPI_ENGINE_CMD_SYNC(
AXI_SPI_ENGINE_CUR_MSG_SYNC_ID));
st->p = p;
st->cmd_buf = p->instructions;
@ -555,10 +542,8 @@ static int spi_engine_prepare_message(struct spi_controller *host,
static int spi_engine_unprepare_message(struct spi_controller *host,
struct spi_message *msg)
{
struct spi_engine *spi_engine = spi_controller_get_devdata(host);
struct spi_engine_message_state *st = msg->state;
ida_free(&spi_engine->sync_ida, st->sync_id);
kfree(st->p);
kfree(st);
@ -640,7 +625,6 @@ static int spi_engine_probe(struct platform_device *pdev)
spi_engine = spi_controller_get_devdata(host);
spin_lock_init(&spi_engine->lock);
ida_init(&spi_engine->sync_ida);
timer_setup(&spi_engine->watchdog_timer, spi_engine_timeout, TIMER_IRQSAFE);
spi_engine->controller = host;