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SubjectRe: [PATCH] drivers: soc: xilinx: Call InitFinalize from late_initcall_sync instead of probe
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On 23. 07. 20 1:25, Amit Sunil Dhamne wrote:
> From: Rajan Vaja <rajan.vaja@xilinx.com>
>
> Initially all devices are in power up state. Firmware expect that
> processor should call InitFinalize API once it have requested devices
> which are required so that it can turn off all unused devices and
> save power. From Linux, PM driver calls InitFinalize to inform the
> firmware that it can power down the unused devices. Upon
> InitFinalize() call firmware power downs all unused devices.
>
> There are chances that PM driver is probed along with or before other
> device drivers. So in that case some of the devices may not be
> requested from firmware which is done by genpd driver. Due to that
> firmware will consider those devices as unused and firmware will power
> down those devices. Later when any device driver is probed, genpd
> driver will ask firmware to power up that device using request node
> API. So for those devices, power transition will be like on->off->on
> which creates unnecessary power glitch to those devices.
>
> To avoid such unnecessary power transitions and as ideal behavior
> InitFinalize should be called after all drivers are probed. So call
> InitFinalize from late_initcall_sync.
>
> Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
> Signed-off-by: Amit Sunil Dhamne <amit.sunil.dhamne@xilinx.com>
> ---
> drivers/soc/xilinx/zynqmp_power.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/soc/xilinx/zynqmp_power.c b/drivers/soc/xilinx/zynqmp_power.c
> index 31ff49fcd078..fa05cf12d5f3 100644
> --- a/drivers/soc/xilinx/zynqmp_power.c
> +++ b/drivers/soc/xilinx/zynqmp_power.c
> @@ -178,7 +178,6 @@ static int zynqmp_pm_probe(struct platform_device *pdev)
> u32 pm_api_version;
> struct mbox_client *client;
>
> - zynqmp_pm_init_finalize();
> zynqmp_pm_get_api_version(&pm_api_version);
>
> /* Check PM API version number */
> @@ -246,6 +245,13 @@ static int zynqmp_pm_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static int __init do_init_finalize(void)
> +{
> + return zynqmp_pm_init_finalize();
> +}
> +
> +late_initcall_sync(do_init_finalize);
> +
> static const struct of_device_id pm_of_match[] = {
> { .compatible = "xlnx,zynqmp-power", },
> { /* end of table */ },
>

Applied.
M

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