[PATCH] spi: atmel: Fix scheduling while atomic
Alexandre Belloni
alexandre.belloni at free-electrons.com
Mon Nov 14 05:08:47 PST 2016
Hi,
On 10/11/2016 at 15:34:50 +0000, ben.whitten at gmail.com wrote :
> From: Ben Whitten <ben.whitten at lairdtech.com>
>
> A call to clk_get_rate appears to be called in the context of an interrupt,
> cache the bus clock for the frequency calculations in transmission.
>
> This fixes a 'BUG: scheduling while atomic' and
> 'WARNING: CPU: 0 PID: 777 at kernel/sched/core.c:2960 atmel_spi_unlock'
>
> Signed-off-by: Ben Whitten <ben.whitten at lairdtech.com>
> Signed-off-by: Steve deRosier <steve.derosier at lairdtech.com>
The spi subsystem maintainer is not copied so this fix will not be
applied.
Else, it seems ok to me.
> ---
> drivers/spi/spi-atmel.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
> index 8feac59..c281d1a 100644
> --- a/drivers/spi/spi-atmel.c
> +++ b/drivers/spi/spi-atmel.c
> @@ -295,6 +295,7 @@ struct atmel_spi {
> int irq;
> struct clk *clk;
> struct platform_device *pdev;
> + unsigned long spi_clk;
>
> struct spi_transfer *current_transfer;
> int current_remaining_bytes;
> @@ -864,7 +865,7 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
> unsigned long bus_hz;
>
> /* v1 chips start out at half the peripheral bus speed. */
> - bus_hz = clk_get_rate(as->clk);
> + bus_hz = as->spi_clk;
> if (!atmel_spi_is_v2(as))
> bus_hz /= 2;
>
> @@ -1606,6 +1607,9 @@ static int atmel_spi_probe(struct platform_device *pdev)
> ret = clk_prepare_enable(clk);
> if (ret)
> goto out_free_irq;
> +
> + as->spi_clk = clk_get_rate(clk);
> +
> spi_writel(as, CR, SPI_BIT(SWRST));
> spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
> if (as->caps.has_wdrbt) {
> --
> 2.7.4
>
>
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--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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