On Tue, Sep 02, 2014 at 09:04:37PM -0700, Tim Harvey wrote:
> According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable
> for SS function) must remain deasserted until the reference clock is running
> at the appropriate frequency.
>
> Without this patch we find a high link failure rate (>5%) on certain
> IMX6 boards at various temperatures.
>
> Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> Tested-by: Fabio Estevam <festevam@xxxxxxxxx>
> Acked-by: Marek Vasut <marex@xxxxxxx>
I'm looking for the comment update requested by Richard, and an ack from
Richard and/or Lucas. Also, please add the stable tag if you want it
(see Documentation/stable_kernel_rules.txt for details).
Bjorn
> ---
>
> v2:
> - added Tested-by Fabio Estevam
> - added Acked-by Marek Vasut
>
> ---
> drivers/pci/host/pci-imx6.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> index 1be6073..9b6bab9 100644
> --- a/drivers/pci/host/pci-imx6.c
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -256,11 +256,6 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
> struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
> int ret;
>
> - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> - IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
> - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> - IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
> -
> ret = clk_prepare_enable(imx6_pcie->pcie_phy);
> if (ret) {
> dev_err(pp->dev, "unable to enable pcie_phy clock\n");
> @@ -282,6 +277,12 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
> /* allow the clocks to stabilize */
> usleep_range(200, 500);
>
> + /* power up core phy and enable ref clock */
> + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
> + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
> +
> /* Some boards don't have PCIe reset GPIO. */
> if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> gpio_set_value(imx6_pcie->reset_gpio, 0);
> --
> 1.8.3.2
>
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