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spi: axi-spi-engine: add watchdog timer

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If there is an issue with the AXI SPI Engine hardware a scheduled
transfer might never be completed and spi_sync() will block forever.
This due to the uninterruptible wait for completion waiting for the
spi_finalize_current_message() that never comes.

Add a watchdog timer that will abort a transfer 5 seconds after it has
been started. This will potentially leave the hardware in a broken state
but it allows software to recover and allow to better diagnose the
underlying issue.

Co-developed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-9-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
David Lechner 2023-12-04 11:33:35 -06:00 committed by Mark Brown
parent 0db60d821e
commit 07d33c2810
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 26 additions and 3 deletions
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29
drivers/spi/spi-axi-spi-engine.c
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@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/timer.h>
#define SPI_ENGINE_VERSION_MAJOR(x) ((x >> 16) & 0xff)
#define SPI_ENGINE_VERSION_MINOR(x) ((x >> 8) & 0xff)
@ -114,6 +115,8 @@ struct spi_engine {
void __iomem *base;
struct ida sync_ida;
struct timer_list watchdog_timer;
struct spi_controller *controller;
unsigned int int_enable;
};
@ -488,9 +491,11 @@ static irqreturn_t spi_engine_irq(int irq, void *devid)
struct spi_engine_message_state *st = msg->state;
if (completed_id == st->sync_id) {
msg->status = 0;
msg->actual_length = msg->frame_length;
spi_finalize_current_message(host);
if (timer_delete_sync(&spi_engine->watchdog_timer)) {
msg->status = 0;
msg->actual_length = msg->frame_length;
spi_finalize_current_message(host);
}
disable_int |= SPI_ENGINE_INT_SYNC;
}
}
@ -573,6 +578,8 @@ static int spi_engine_transfer_one_message(struct spi_controller *host,
unsigned int int_enable = 0;
unsigned long flags;
mod_timer(&spi_engine->watchdog_timer, jiffies + msecs_to_jiffies(5000));
spin_lock_irqsave(&spi_engine->lock, flags);
if (spi_engine_write_cmd_fifo(spi_engine, msg))
@ -596,6 +603,20 @@ static int spi_engine_transfer_one_message(struct spi_controller *host,
return 0;
}
static void spi_engine_timeout(struct timer_list *timer)
{
struct spi_engine *spi_engine = from_timer(spi_engine, timer, watchdog_timer);
struct spi_controller *host = spi_engine->controller;
if (WARN_ON(!host->cur_msg))
return;
dev_err(&host->dev,
"Timeout occurred while waiting for transfer to complete. Hardware is probably broken.\n");
host->cur_msg->status = -ETIMEDOUT;
spi_finalize_current_message(host);
}
static void spi_engine_release_hw(void *p)
{
struct spi_engine *spi_engine = p;
@ -625,6 +646,8 @@ static int spi_engine_probe(struct platform_device *pdev)
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;
spi_engine->clk = devm_clk_get_enabled(&pdev->dev, "s_axi_aclk");
if (IS_ERR(spi_engine->clk))