[PATCH] [v4] spi: spi-zynqmp-gqspi: Fix runtime PM imbalance in zynqmp_qspi_probe

[quanyang.wang]

On 4/15/21 3:46 PM, Dinghao Liu wrote:
> There is a PM usage counter decrement after zynqmp_qspi_init_hw()
> without any refcount increment, which leads to refcount leak.Add
> a refcount increment to balance the refcount. Also set
> auto_runtime_pm to resume suspended spi controller.
>
> Fixes: 9e3a000362aec ("spi: zynqmp: Add pm runtime support")
> Signed-off-by: Dinghao Liu <dinghao.liu at zju.edu.cn>
> ---
>
> Changelog:
>
> v2: - Add a refcount increment to fix refcout leak instead of the
>        refcount decrement on error.
>        Set ctlr->auto_runtime_pm = true.
>
> v3: - Add fix tag.
>        Add a return value check against pm_runtime_get_sync().
>        Move pm_runtime_{mark_last_busy & put_autosuspend} to the
>        end of current function.
>
> v4: - Add error message on failure of pm_runtime_get_sync().
> ---
>   drivers/spi/spi-zynqmp-gqspi.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
> index c8fa6ee18ae7..38f3ddd3ea7c 100644
> --- a/drivers/spi/spi-zynqmp-gqspi.c
> +++ b/drivers/spi/spi-zynqmp-gqspi.c
> @@ -1160,11 +1160,16 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
>   	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
>   	pm_runtime_set_active(&pdev->dev);
>   	pm_runtime_enable(&pdev->dev);
> +
> +	ret = pm_runtime_get_sync(&pdev->dev);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to pm_runtime_get_sync: %d\n", ret);
> +		goto clk_dis_all;
> +	}
> +
>   	/* QSPI controller initializations */
>   	zynqmp_qspi_init_hw(xqspi);
>   
> -	pm_runtime_mark_last_busy(&pdev->dev);
> -	pm_runtime_put_autosuspend(&pdev->dev);
>   	xqspi->irq = platform_get_irq(pdev, 0);
>   	if (xqspi->irq <= 0) {
>   		ret = -ENXIO;
> @@ -1187,6 +1192,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
>   	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD |
>   			    SPI_TX_DUAL | SPI_TX_QUAD;
>   	ctlr->dev.of_node = np;
> +	ctlr->auto_runtime_pm = true;
>   
>   	ret = devm_spi_register_controller(&pdev->dev, ctlr);
>   	if (ret) {
> @@ -1194,9 +1200,13 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
>   		goto clk_dis_all;
>   	}
>   
> +	pm_runtime_mark_last_busy(&pdev->dev);
> +	pm_runtime_put_autosuspend(&pdev->dev);
> +
>   	return 0;
>   
>   clk_dis_all:
> +	pm_runtime_put_sync(&pdev->dev);
>   	pm_runtime_set_suspended(&pdev->dev);
>   	pm_runtime_disable(&pdev->dev);
>   	clk_disable_unprepare(xqspi->refclk);

Test this patch at zcu102 board:

root at xilinx-zynqmp:~# dmesg | grep domain2
[    0.905407] zynqmp_gpd_attach_dev() ff0f0000.spi attached to domain2 
domain
[    0.912390] zynqmp_gpd_power_on() Powered on domain2 domain
[    4.350331] zynqmp_gpd_power_off() Powered off domain2 domain
root at xilinx-zynqmp:~# flash_erase /dev/mtd3 0 0
Erasing 4 Kibyte @ 0 --  0 % complete [  153.125894] 
zynqmp_gpd_power_on() Powered on domain2 domain
Erasing 4 Kibyte @ 2e8000 -- 49 % complete [  156.134884] 
zynqmp_gpd_power_off() Powered off domain2 domain
[  156.142648] zynqmp_gpd_power_on() Powered on domain2 domain
Erasing 4 Kibyte @ 5d5000 -- 99 % complete [  159.148329] 
zynqmp_gpd_power_off() Powered off domain2 domain
[  159.154579] zynqmp_gpd_power_on() Powered on domain2 domain
Erasing 4 Kibyte @ 5df000 -- 100 % complete
root at xilinx-zynqmp:~# [  162.910329] zynqmp_gpd_power_off() Powered off 
domain2 domain

pm_runtime works now. So

Tested-by: Quanyang Wang <quanyang.wang at windriver.com>

Regards,

Quanyang