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

[Andrea della Porta <andrea.porta@suse.com>]

On 08:55 Sun 14 Apr     , Florian Fainelli wrote:
> 
> 
> 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@suse.com>
> > ---
> >   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.

Ack.

> 
> > +	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()?

No real reason. I assume only the lower boundary is critical so I can use usleep_range instead.
Will be fixed in a future patch, the SD express support will be drpped in V2 since nto strictly
necessary.

> 
> > +
> > +	/* 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.

Ditto.

> 
> > +
> > +	/* 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.

Ack.

> 
> > +		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