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Message-ID: <92621539-4ec5-4aa0-a7da-c6eb87ee1a52@intel.com>
Date: Tue, 2 Jan 2024 12:54:54 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Kamal Dasu <kamal.dasu@...adcom.com>, ulf.hansson@...aro.org,
linux-kernel@...r.kernel.org, alcooperx@...il.com,
linux-arm-kernel@...ts.infradead.org, linux-mmc@...r.kernel.org,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
devicetree@...r.kernel.org
Cc: f.fainelli@...il.com, bcm-kernel-feedback-list@...adcom.com,
Kamal Dasu <kdasu@...adcom.com>
Subject: Re: [PATCH v6 2/2] mmc: add new sdhci reset sequence for brcm 74165b0
On 20/12/23 17:30, Kamal Dasu wrote:
> From: Kamal Dasu <kdasu@...adcom.com>
>
> 74165b0 shall use a new sdio controller core version which
> requires a different reset sequence. For core reset we use
> sdhci_reset. For CMD and/or DATA reset added a new function
> to also enable SDHCI clocks SDHCI_CLOCK_CARD_EN
> SDHCI_CLOCK_INT_EN along with the SDHCI_RESET_CMD and/or
> SDHCI_RESET_DATA fields.
>
> Signed-off-by: Kamal Dasu <kdasu@...adcom.com>
> ---
> drivers/mmc/host/sdhci-brcmstb.c | 67 +++++++++++++++++++++++++++++---
> 1 file changed, 62 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
> index c23251bb95f3..f171980b014e 100644
> --- a/drivers/mmc/host/sdhci-brcmstb.c
> +++ b/drivers/mmc/host/sdhci-brcmstb.c
> @@ -6,6 +6,7 @@
> */
>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/mmc/host.h>
> #include <linux/module.h>
> #include <linux/of.h>
> @@ -44,8 +45,13 @@ struct brcmstb_match_priv {
>
> static inline void enable_clock_gating(struct sdhci_host *host)
> {
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_brcmstb_priv *priv = sdhci_pltfm_priv(pltfm_host);
> u32 reg;
>
> + if (!(priv->flags & BRCMSTB_PRIV_FLAGS_GATE_CLOCK))
> + return;
> +
> reg = sdhci_readl(host, SDHCI_VENDOR);
> reg |= SDHCI_VENDOR_GATE_SDCLK_EN;
> sdhci_writel(host, reg, SDHCI_VENDOR);
> @@ -53,14 +59,51 @@ static inline void enable_clock_gating(struct sdhci_host *host)
>
> static void brcmstb_reset(struct sdhci_host *host, u8 mask)
> {
> - struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> - struct sdhci_brcmstb_priv *priv = sdhci_pltfm_priv(pltfm_host);
> -
> sdhci_and_cqhci_reset(host, mask);
>
> /* Reset will clear this, so re-enable it */
> - if (priv->flags & BRCMSTB_PRIV_FLAGS_GATE_CLOCK)
> - enable_clock_gating(host);
> + enable_clock_gating(host);
> +}
> +
> +static void brcmstb_sdhci_reset_cmd_data(struct sdhci_host *host, u8 mask)
> +{
> + int ret;
> + u32 reg;
> + u32 new_mask = (mask & (SDHCI_RESET_CMD | SDHCI_RESET_DATA)) << 24;
It looks slightly neater if longer lines comes first i.e.
u32 new_mask = (mask & (SDHCI_RESET_CMD | SDHCI_RESET_DATA)) << 24;
u32 reg;
int ret;
> +
> + /*
> + * SDHCI_CLOCK_CONTROL register CARD_EN and CLOCK_INT_EN bits shall
> + * be set along with SOFTWARE_RESET register RESET_CMD or RESET_DATA
> + * bits, hence access SDHCI_CLOCK_CONTROL register as 32-bit register
> + */
> + new_mask |= SDHCI_CLOCK_CARD_EN | SDHCI_CLOCK_INT_EN;
> + reg = sdhci_readl(host, SDHCI_CLOCK_CONTROL);
> + sdhci_writel(host, reg | new_mask, SDHCI_CLOCK_CONTROL);
> +
> + reg = sdhci_readb(host, SDHCI_SOFTWARE_RESET);
> + ret = readb_poll_timeout_atomic(host->ioaddr + SDHCI_SOFTWARE_RESET,
> + reg, reg & mask, 10, 10000);
The break condition does not seem the right way around.
Also read_poll_timeout_atomic() seems neater e.g.
ret = read_poll_timeout_atomic(sdhci_readb, reg, !(reg & mask),
10, 10000, false,
host, SDHCI_SOFTWARE_RESET);
> +
> + if (ret) {
> + pr_err("%s: Reset 0x%x never completed.\n",
> + mmc_hostname(host->mmc), (int)mask);
> + sdhci_err_stats_inc(host, CTRL_TIMEOUT);
> + sdhci_dumpregs(host);
> + }
> +}
> +
> +static void brcmstb_reset_74165b0(struct sdhci_host *host, u8 mask)
> +{
> + /* take care of RESET_ALL as usual */
> + if (mask & SDHCI_RESET_ALL)
> + sdhci_and_cqhci_reset(host, SDHCI_RESET_ALL);
> +
> + /* cmd and/or data treated differently on this core */
> + if (mask & (SDHCI_RESET_CMD | SDHCI_RESET_DATA))
> + brcmstb_sdhci_reset_cmd_data(host, mask);
> +
> + /* Reset will clear this, so re-enable it */
> + enable_clock_gating(host);
> }
>
> static void sdhci_brcmstb_hs400es(struct mmc_host *mmc, struct mmc_ios *ios)
> @@ -162,6 +205,13 @@ static struct sdhci_ops sdhci_brcmstb_ops_7216 = {
> .set_uhs_signaling = sdhci_brcmstb_set_uhs_signaling,
> };
>
> +static struct sdhci_ops sdhci_brcmstb_ops_74165b0 = {
> + .set_clock = sdhci_brcmstb_set_clock,
> + .set_bus_width = sdhci_set_bus_width,
> + .reset = brcmstb_reset_74165b0,
> + .set_uhs_signaling = sdhci_brcmstb_set_uhs_signaling,
> +};
> +
> static struct brcmstb_match_priv match_priv_7425 = {
> .flags = BRCMSTB_MATCH_FLAGS_NO_64BIT |
> BRCMSTB_MATCH_FLAGS_BROKEN_TIMEOUT,
> @@ -179,10 +229,17 @@ static const struct brcmstb_match_priv match_priv_7216 = {
> .ops = &sdhci_brcmstb_ops_7216,
> };
>
> +static struct brcmstb_match_priv match_priv_74165b0 = {
> + .flags = BRCMSTB_MATCH_FLAGS_HAS_CLOCK_GATE,
> + .hs400es = sdhci_brcmstb_hs400es,
> + .ops = &sdhci_brcmstb_ops_74165b0,
> +};
> +
> static const struct of_device_id __maybe_unused sdhci_brcm_of_match[] = {
> { .compatible = "brcm,bcm7425-sdhci", .data = &match_priv_7425 },
> { .compatible = "brcm,bcm7445-sdhci", .data = &match_priv_7445 },
> { .compatible = "brcm,bcm7216-sdhci", .data = &match_priv_7216 },
> + { .compatible = "brcm,bcm74165b0-sdhci", .data = &match_priv_74165b0 },
> {},
> };
>
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