Re: [PATCH v5 09/16] PCI: tegra: set up PADS_REFCLK_CFG1

[Bjorn Helgaas]

On Thu, Jul 25, 2013 at 11:53 AM, Thierry Reding
<thierry.reding@xxxxxxxxx> wrote:
> From: Stephen Warren <swarren@xxxxxxxxxx>
>
> The registers PADS_REFCLK_CFG are an array of 16-bit data, one entry per
> PCIe root port. For Tegra30, we therefore need to write a 3rd entry in
> this array. Doing so mays the mini-PCIe slot on Beaver operate correctly.
>
> While we're at it, add some #defines to partially document the fields
> within these 16-bit values.
>
> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

> ---
>  drivers/pci/host/pci-tegra.c | 29 ++++++++++++++++++++++++-----
>  1 file changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
> index 5347d7d..0c84c67 100644
> --- a/drivers/pci/host/pci-tegra.c
> +++ b/drivers/pci/host/pci-tegra.c
> @@ -196,6 +196,25 @@
>  #define PADS_REFCLK_CFG0                       0x000000C8
>  #define PADS_REFCLK_CFG1                       0x000000CC
>
> +/*
> + * Fields in PADS_REFCLK_CFG*. Those registers form an array of 16-bit
> + * entries, one entry per PCIe port. These field definitions and desired
> + * values aren't in the TRM, but do come from NVIDIA.
> + */
> +#define PADS_REFCLK_CFG_TERM_SHIFT             2  /* 6:2 */
> +#define PADS_REFCLK_CFG_E_TERM_SHIFT           7
> +#define PADS_REFCLK_CFG_PREDI_SHIFT            8  /* 11:8 */
> +#define PADS_REFCLK_CFG_DRVI_SHIFT             12 /* 15:12 */
> +
> +/* Default value provided by HW engineering is 0xfa5c */
> +#define PADS_REFCLK_CFG_VALUE \
> +       ( \
> +               (0x17 << PADS_REFCLK_CFG_TERM_SHIFT)   | \
> +               (0    << PADS_REFCLK_CFG_E_TERM_SHIFT) | \
> +               (0xa  << PADS_REFCLK_CFG_PREDI_SHIFT)  | \
> +               (0xf  << PADS_REFCLK_CFG_DRVI_SHIFT)     \
> +       )
> +
>  struct tegra_msi {
>         struct msi_chip chip;
>         DECLARE_BITMAP(used, INT_PCI_MSI_NR);
> @@ -809,11 +828,11 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie)
>         value |= PADS_PLL_CTL_RST_B4SM;
>         pads_writel(pcie, value, soc->pads_pll_ctl);
>
> -       /*
> -        * Hack, set the clock voltage to the DEFAULT provided by hw folks.
> -        * This doesn't exist in the documentation.
> -        */
> -       pads_writel(pcie, 0xfa5cfa5c, PADS_REFCLK_CFG0);
> +       /* Configure the reference clock driver */
> +       value = PADS_REFCLK_CFG_VALUE | (PADS_REFCLK_CFG_VALUE << 16);
> +       pads_writel(pcie, value, PADS_REFCLK_CFG0);
> +       if (soc->num_ports > 2)
> +               pads_writel(pcie, PADS_REFCLK_CFG_VALUE, PADS_REFCLK_CFG1);
>
>         /* wait for the PLL to lock */
>         timeout = 300;
> --
> 1.8.1.5
>
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