| Message ID | 20240206-axi-spi-engine-round-2-1-v1-1-ea6eeb60f4fb@baylibre.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/2] spi: axi-spi-engine: remove use of ida for sync id | expand |
On Tue, 2024-02-06 at 14:31 -0600, David Lechner wrote: > 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. > > Signed-off-by: David Lechner <dlechner@baylibre.com> > --- With the removed header: Reviewed-by: Nuno Sa <nuno.sa@analog.com> (Christophe suggestion is also pretty good but I would likely do it in a different patch - maybe we could even annotate the flex array with __counted_by) - Nuno Sá > drivers/spi/spi-axi-spi-engine.c | 27 ++++++--------------------- > 1 file changed, 6 insertions(+), 21 deletions(-) > > diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi- > engine.c > index 6b0c72bf3395..9cc602075c17 100644 > --- a/drivers/spi/spi-axi-spi-engine.c > +++ b/drivers/spi/spi-axi-spi-engine.c > @@ -57,6 +57,9 @@ > #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 +101,6 @@ 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 +110,6 @@ struct spi_engine { > spinlock_t lock; > > void __iomem *base; > - struct ida sync_ida; > struct timer_list watchdog_timer; > struct spi_controller *controller; > > @@ -483,9 +483,7 @@ 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 +508,8 @@ 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 +527,10 @@ 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_I > D)); > > st->p = p; > st->cmd_buf = p->instructions; > @@ -555,10 +543,8 @@ 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 +626,6 @@ 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; > >
diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c index 6b0c72bf3395..9cc602075c17 100644 --- a/drivers/spi/spi-axi-spi-engine.c +++ b/drivers/spi/spi-axi-spi-engine.c @@ -57,6 +57,9 @@ #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 +101,6 @@ 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 +110,6 @@ struct spi_engine { spinlock_t lock; void __iomem *base; - struct ida sync_ida; struct timer_list watchdog_timer; struct spi_controller *controller; @@ -483,9 +483,7 @@ 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 +508,8 @@ 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 +527,10 @@ 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 +543,8 @@ 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 +626,6 @@ 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;
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. Signed-off-by: David Lechner <dlechner@baylibre.com> --- drivers/spi/spi-axi-spi-engine.c | 27 ++++++--------------------- 1 file changed, 6 insertions(+), 21 deletions(-)