[PATCH v5 5/6] PCI: mediatek-gen3: Add reset delay in mtk_pcie_en7581_power_up()

[Bjorn Helgaas]

If you repost this series, here are a few comments/typos.  Otherwise
we can do the trivial updates on the branch.

In subject: this patch doesn't *add* a delay; it *moves* it.

On Sat, Nov 30, 2024 at 12:20:14AM +0100, Lorenzo Bianconi wrote:
> Airoha EN7581 has a hw bug asserting/releasing PCIE_PE_RSTB signal
> causing occasional PCIe link down issues. In order to overcome the
> problem, PCIe block is reset using REG_PCI_CONTROL (0x88) and
> REG_RESET_CONTROL (0x834) registers available in the clock module
> running clk_bulk_prepare_enable in mtk_pcie_en7581_power_up().

Add parens after clk_bulk_prepare_enable.

> In order to make the code more readable, move the wait for the time
> needed to complete the PCIe reset from en7581_pci_enable() to
> mtk_pcie_en7581_power_up().
> Reduce reset timeout from 250ms to the standard PCIE_T_PVPERL_MS value
> (100ms) since it has no impact on the driver behavior.
>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> Acked-by: Stephen Boyd <sboyd at kernel.org>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo at kernel.org>
> ---
>  drivers/clk/clk-en7523.c                    | 1 -
>  drivers/pci/controller/pcie-mediatek-gen3.c | 7 +++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-en7523.c b/drivers/clk/clk-en7523.c
> index 22fbea61c3dcc05e63f8fa37e203c62b2a6fe79e..bf9d9594bef8a54316e28e56a1642ecb0562377a 100644
> --- a/drivers/clk/clk-en7523.c
> +++ b/drivers/clk/clk-en7523.c
> @@ -393,7 +393,6 @@ static int en7581_pci_enable(struct clk_hw *hw)
>  	       REG_PCI_CONTROL_PERSTOUT;
>  	val = readl(np_base + REG_PCI_CONTROL);
>  	writel(val | mask, np_base + REG_PCI_CONTROL);
> -	msleep(250);
>  
>  	return 0;
>  }
> diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
> index 01e8fde96080fa55f6c23c7d1baab6e22c49fcff..da01e741ff290464d28e172879520dbe0670cc41 100644
> --- a/drivers/pci/controller/pcie-mediatek-gen3.c
> +++ b/drivers/pci/controller/pcie-mediatek-gen3.c
> @@ -977,6 +977,13 @@ static int mtk_pcie_en7581_power_up(struct mtk_gen3_pcie *pcie)
>  		goto err_clk_prepare_enable;
>  	}
>  
> +	/*
> +	 * Airoha EN7581 performs PCIe reset via clk callabacks since it has a
> +	 * hw issue with PCIE_PE_RSTB signal. Add wait for the time needed to
> +	 * complete the PCIe reset.

s/callabacks/callbacks/

> +	 */
> +	msleep(PCIE_T_PVPERL_MS);
> +
>  	return 0;
>  
>  err_clk_prepare_enable:
> 
> -- 
> 2.47.0
>