Re: [PATCH 6/6] mmc: sdhci-brcmstb: Add BCM2712 SD Express support

From: Florian Fainelli
Date: Sun Apr 14 2024 - 11:56:01 EST




On 4/13/2024 3:14 PM, Andrea della Porta wrote:
Broadcom BCM2712 SDHCI controller is SD Express capable. Add support
for sde capability where the implementation is based on downstream driver,
diverging from it in the way that init_sd_express callback is invoked:
in downstream the sdhci_ops structure has been augmented with a new
function ptr 'init_sd_express' that just propagate the call to the
driver specific callback so that the callstack from a structure
standpoint is mmc_host_ops -> sdhci_ops. The drawback here is in the
added level of indirection (the newly added init_sd_express is
redundant) and the sdhci_ops structure declaration has to be changed.
To overcome this the presented approach consist in patching the mmc_host_ops
init_sd_express callback to point directly to the custom function defined in
this driver (see struct brcmstb_match_priv).

Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
---
drivers/mmc/host/Kconfig | 1 +
drivers/mmc/host/sdhci-brcmstb.c | 147 ++++++++++++++++++++++++++++++-
2 files changed, 147 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index aebc587f77a7..343ccac1a4e4 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -1018,6 +1018,7 @@ config MMC_SDHCI_BRCMSTB
depends on ARCH_BRCMSTB || BMIPS_GENERIC || COMPILE_TEST
depends on MMC_SDHCI_PLTFM
select MMC_CQHCI
+ select OF_DYNAMIC
default ARCH_BRCMSTB || BMIPS_GENERIC
help
This selects support for the SDIO/SD/MMC Host Controller on
diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
index 907a4947abe5..56fb34a75ec2 100644
--- a/drivers/mmc/host/sdhci-brcmstb.c
+++ b/drivers/mmc/host/sdhci-brcmstb.c
@@ -29,6 +29,7 @@
#define BRCMSTB_PRIV_FLAGS_HAS_CQE BIT(0)
#define BRCMSTB_PRIV_FLAGS_GATE_CLOCK BIT(1)
+#define BRCMSTB_PRIV_FLAGS_HAS_SD_EXPRESS BIT(2)
#define SDHCI_ARASAN_CQE_BASE_ADDR 0x200
@@ -50,13 +51,19 @@ struct sdhci_brcmstb_priv {
unsigned int flags;
struct clk *base_clk;
u32 base_freq_hz;
+ struct regulator *sde_1v8;
+ struct device_node *sde_pcie;
+ void *__iomem sde_ioaddr;
+ void *__iomem sde_ioaddr2;
struct pinctrl *pinctrl;
struct pinctrl_state *pins_default;
+ struct pinctrl_state *pins_sdex;
};
struct brcmstb_match_priv {
void (*hs400es)(struct mmc_host *mmc, struct mmc_ios *ios);
void (*cfginit)(struct sdhci_host *host);
+ int (*init_sd_express)(struct mmc_host *mmc, struct mmc_ios *ios);
struct sdhci_ops *ops;
const unsigned int flags;
};
@@ -263,6 +270,105 @@ static void sdhci_brcmstb_cfginit_2712(struct sdhci_host *host)
}
}
+static int bcm2712_init_sd_express(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_brcmstb_priv *brcmstb_priv = sdhci_pltfm_priv(pltfm_host);
+ struct device *dev = host->mmc->parent;
+ u32 ctrl_val;
+ u32 present_state;
+ int ret;
+
+ if (!brcmstb_priv->sde_ioaddr || !brcmstb_priv->sde_ioaddr2)
+ return -EINVAL;
+
+ if (!brcmstb_priv->pinctrl)
+ return -EINVAL;
+
+ /* Turn off the SD clock first */
+ sdhci_set_clock(host, 0);
+
+ /* Disable SD DAT0-3 pulls */
+ pinctrl_select_state(brcmstb_priv->pinctrl, brcmstb_priv->pins_sdex);
+
+ ctrl_val = readl(brcmstb_priv->sde_ioaddr);
+ dev_dbg(dev, "ctrl_val 1 %08x\n", ctrl_val);
+
+ /* Tri-state the SD pins */
+ ctrl_val |= 0x1ff8;

No magic values please.

+ writel(ctrl_val, brcmstb_priv->sde_ioaddr);
+ dev_dbg(dev, "ctrl_val 1->%08x (%08x)\n", ctrl_val, readl(brcmstb_priv->sde_ioaddr));
+ /* Let voltages settle */
+ udelay(100);

Why not usleep_range()?

+
+ /* Enable the PCIe sideband pins */
+ ctrl_val &= ~0x6000;

No magic values please.

+ writel(ctrl_val, brcmstb_priv->sde_ioaddr);
+ dev_dbg(dev, "ctrl_val 1->%08x (%08x)\n", ctrl_val, readl(brcmstb_priv->sde_ioaddr));
+ /* Let voltages settle */
+ udelay(100);

Likewise.

+
+ /* Turn on the 1v8 VDD2 regulator */
+ ret = regulator_enable(brcmstb_priv->sde_1v8);
+ if (ret)
+ return ret;
+
+ /* Wait for Tpvcrl */
+ msleep(1);
+
+ /* Sample DAT2 (CLKREQ#) - if low, card is in PCIe mode */
+ present_state = sdhci_readl(host, SDHCI_PRESENT_STATE);
+ present_state = (present_state & SDHCI_DATA_LVL_MASK) >> SDHCI_DATA_LVL_SHIFT;
+ dev_dbg(dev, "state = 0x%08x\n", present_state);
+
+ if (present_state & BIT(2)) {

Likewise, replace with constant.

+ dev_err(dev, "DAT2 still high, abandoning SDex switch\n");
+ return -ENODEV;
+ }
+
+ /* Turn on the LCPLL PTEST mux */
+ ctrl_val = readl(brcmstb_priv->sde_ioaddr2 + 20); // misc5
+ ctrl_val &= ~(0x7 << 7);
+ ctrl_val |= 3 << 7;
+ writel(ctrl_val, brcmstb_priv->sde_ioaddr2 + 20);
+ dev_dbg(dev, "misc 5->%08x (%08x)\n", ctrl_val, readl(brcmstb_priv->sde_ioaddr2 + 20));
+
+ /* PTEST diff driver enable */
+ ctrl_val = readl(brcmstb_priv->sde_ioaddr2);
+ ctrl_val |= BIT(21);
+ writel(ctrl_val, brcmstb_priv->sde_ioaddr2);
+
+ dev_dbg(dev, "misc 0->%08x (%08x)\n", ctrl_val, readl(brcmstb_priv->sde_ioaddr2));
+
+ /* Wait for more than the minimum Tpvpgl time */
+ msleep(100);
+
+ if (brcmstb_priv->sde_pcie) {
+ struct of_changeset changeset;
+ static struct property okay_property = {
+ .name = "status",
+ .value = "okay",
+ .length = 5,
+ };
+
+ /* Enable the pcie controller */
+ of_changeset_init(&changeset);
+ ret = of_changeset_update_property(&changeset,
+ brcmstb_priv->sde_pcie,
+ &okay_property);
+ if (ret) {
+ dev_err(dev, "%s: failed to update property - %d\n", __func__,
+ ret);
+ return -ENODEV;
+ }
+ ret = of_changeset_apply(&changeset);
+ }

Why are you doing this? Cannot the firmware enable/disable the node according to the boot mode or something else?

This is not going to fly for upstream, sorry.
--
Florian

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