git.openwrt.org Git - openwrt/staging/ansuel.git/blob

   1 From fd051511cd5e7e38315adfe728b1481cbe480331 Mon Sep 17 00:00:00 2001
   2 From: Jonathan Bell <jonathan@raspberrypi.com>
   3 Date: Tue, 4 Jun 2024 09:51:17 +0100
   4 Subject: [PATCH 1112/1135] mmc: sdhci-brcmstb: add hs400_downgrade callback
   5  for bcm2712
   6
   7 The attached PHY performs parameter validation, so the switch from HS200
   8 to HS (before selecting HS400/HS400es) with a 200MHz clock fails to
   9 update pad timings and results in CRC errors from the card.
  10
  11 Underclocking the interface is safe, so do that in the downgrade callback.
  12
  13 Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
  14 ---
  15  drivers/mmc/host/sdhci-brcmstb.c | 16 ++++++++++++++++
  16  1 file changed, 16 insertions(+)
  17
  18 --- a/drivers/mmc/host/sdhci-brcmstb.c
  19 +++ b/drivers/mmc/host/sdhci-brcmstb.c
  20 @@ -197,6 +197,20 @@ static void sdhci_brcmstb_set_uhs_signal
  21         sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
  22  }
  23
  24 +static void sdhci_bcm2712_hs400_downgrade(struct mmc_host *mmc)
  25 +{
  26 +       struct sdhci_host *host = mmc_priv(mmc);
  27 +       /*
  28 +        * The eMMC PHY and its internal controller parses and validates
  29 +        * the uhs_mode, divisor, pin_sel, and sampling clock select
  30 +        * output from the SD controller. It will refuse to update its
  31 +        * config if HS timings are selected while the clock is >52MHz.
  32 +        * so bump the clock down now before card/controller setup is
  33 +        * performed.
  34 +        */
  35 +       sdhci_bcm2712_set_clock(host, 52000000);
  36 +}
  37 +
  38  static void sdhci_brcmstb_cfginit_2712(struct sdhci_host *host)
  39  {
  40         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
  41 @@ -215,6 +229,8 @@ static void sdhci_brcmstb_cfginit_2712(s
  42                 reg &= ~SDIO_CFG_MAX_50MHZ_MODE_ENABLE;
  43                 reg |= SDIO_CFG_MAX_50MHZ_MODE_STRAP_OVERRIDE;
  44                 writel(reg, brcmstb_priv->cfg_regs + SDIO_CFG_MAX_50MHZ_MODE);
  45 +
  46 +               host->mmc_host_ops.hs400_downgrade = sdhci_bcm2712_hs400_downgrade;
  47         }
  48
  49         if ((host->mmc->caps & MMC_CAP_NONREMOVABLE) ||