Re: [PATCH v3 09/11] PCI: brcmstb: Adjust PHY PLL setup to use a 54MHz input refclk

Florian Fainelli
2024-10-14T17:11:58Z

On 10/14/24 06:07, Stanimir Varbanov wrote:
> Use canned MDIO writes from Broadcom that switch the ref_clk output
> pair to run from the internal fractional PLL, and set the internal
> PLL to expect a 54MHz input reference clock.
>
> Without this RPi5 PCIe cannot enumerate endpoint devices on
> extension connector.

You could say that the default reference clock for the PLL is 100MHz,
except for some devices, where it is 54MHz, like 2712d0. AFAIR, 2712c1
might have been 100MHz as well, so whether we need to support that
revision of the chip or not might be TBD.

>
> Signed-off-by: Stanimir Varbanov <svarbanov@suse.de>
> ---
> v2 -> v3:
> - New patch.
>
> drivers/pci/controller/pcie-brcmstb.c | 35 +++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index 407343a30439..12591e292c0c 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -55,6 +55,10 @@
> #define PCIE_RC_DL_MDIO_WR_DATA 0x1104
> #define PCIE_RC_DL_MDIO_RD_DATA 0x1108
>
> +#define PCIE_RC_PL_PHY_CTL_15 0x184c
> +#define PCIE_RC_PL_PHY_CTL_15_DIS_PLL_PD_MASK 0x400000
> +#define PCIE_RC_PL_PHY_CTL_15_PM_CLK_PERIOD_MASK 0xff
> +
> #define PCIE_MISC_MISC_CTRL 0x4008
> #define PCIE_MISC_MISC_CTRL_PCIE_RCB_64B_MODE_MASK 0x80
> #define PCIE_MISC_MISC_CTRL_PCIE_RCB_MPS_MODE_MASK 0x400
> @@ -251,6 +255,7 @@ struct pcie_cfg_data {
> u8 num_inbound_wins;
> int (*perst_set)(struct brcm_pcie *pcie, u32 val);
> int (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
> + int (*post_setup)(struct brcm_pcie *pcie);
> };
>
> struct subdev_regulators {
> @@ -826,6 +831,32 @@ static int brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val)
> return 0;
> }
>
> +static int brcm_pcie_post_setup_bcm2712(struct brcm_pcie *pcie)
> +{
> + const u16 data[] = { 0x50b9, 0xbda1, 0x0094, 0x97b4, 0x5030, 0x5030, 0x0007 };
> + const u8 regs[] = { 0x16, 0x17, 0x18, 0x19, 0x1b, 0x1c, 0x1e };
> + u32 tmp;
> + int i;
> +
> + /* Allow a 54MHz (xosc) refclk source */
> +

This newline is not necessary. Other than that:

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
--
Florian