From: haibo.chen@nxp.com
To: adrian.hunter@intel.com, ulf.hansson@linaro.org,
shawnguo@kernel.org, robh+dt@kernel.org, s.hauer@pengutronix.de
Cc: kernel@pengutronix.de, festevam@gmail.com,
linux-mmc@vger.kernel.org, linux-imx@nxp.com, haibo.chen@nxp.com,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/6] mmc: host: sdhci-esdhc-imx.c: correct the auto-tuning setting for sdio device
Date: Mon, 16 Aug 2021 20:38:26 +0800 [thread overview]
Message-ID: <1629117508-4886-4-git-send-email-haibo.chen@nxp.com> (raw)
In-Reply-To: <1629117508-4886-1-git-send-email-haibo.chen@nxp.com>
From: Haibo Chen <haibo.chen@nxp.com>
USDHC contain auto tuning circuit, this circuit will work automatically after
the tuning procedurae, it can increase/decrease the delay cell according to
the outside environment change (like temperature).
Unfortunately, this auto tuning circuit can not handle the async sdio device
interrupt correctly. When sdio device use 4 data line, async sdio interrupt
will use DAT[1], if we enable auto tuning circuit check 4 data lines, include
the DAT[1], this circuit will detect this interrupt, take this as a data on
DAT[1], and adjust the delay cell wrongly.
This is the hardware design limitation, to avoid this, when sdio device enable
async interrupt, auto tuning circuit only check DAT[0] and CMD lines.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
---
drivers/mmc/host/sdhci-esdhc-imx.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index f18d169bc8ff..ab84c29777e5 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -226,6 +226,7 @@ struct esdhc_platform_data {
unsigned int tuning_step; /* The delay cell steps in tuning procedure */
unsigned int tuning_start_tap; /* The start delay cell point in tuning procedure */
unsigned int strobe_dll_delay_target; /* The delay cell for strobe pad (read clock) */
+ bool sdio_async_interrupt_enabled; /* sdio device enable the async interrupt */
};
struct esdhc_soc_data {
@@ -416,6 +417,8 @@ static inline void esdhc_wait_for_card_clock_gate_off(struct sdhci_host *host)
/* Enable the auto tuning circuit to check the CMD line and BUS line */
static inline void usdhc_auto_tuning_mode_sel(struct sdhci_host *host)
{
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
u32 buswidth, auto_tune_buswidth;
buswidth = USDHC_GET_BUSWIDTH(readl(host->ioaddr + SDHCI_HOST_CONTROL));
@@ -432,6 +435,18 @@ static inline void usdhc_auto_tuning_mode_sel(struct sdhci_host *host)
break;
}
+ /*
+ * If sdio device use async interrupt, it will use DAT[1] to signal
+ * the device's interrupt asynchronous when use 4 data lines.
+ * Then hardware auto tuning circuit MUST NOT check the DAT[1] line,
+ * otherwise auto tuning will be impacted by this async interrupt,
+ * and change the delay cell incorrectly, which then cause data/cmd
+ * errors.
+ * This is the hardware auto tuning circuit limitation.
+ */
+ if (imx_data->boarddata.sdio_async_interrupt_enabled)
+ auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_1BIT_EN;
+
esdhc_clrset_le(host, ESDHC_VEND_SPEC2_AUTO_TUNE_MODE_MASK,
auto_tune_buswidth | ESDHC_VEND_SPEC2_AUTO_TUNE_CMD_EN,
ESDHC_VEND_SPEC2);
@@ -1531,6 +1546,9 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
if (of_property_read_u32(np, "fsl,delay-line", &boarddata->delay_line))
boarddata->delay_line = 0;
+ if (of_property_read_bool(np, "fsl,sdio-async-interrupt-enabled"))
+ boarddata->sdio_async_interrupt_enabled = true;
+
mmc_of_parse_voltage(host->mmc, &host->ocr_mask);
if (esdhc_is_usdhc(imx_data) && !IS_ERR(imx_data->pinctrl)) {
--
2.17.1
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next prev parent reply other threads:[~2021-08-16 13:03 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-16 12:38 [PATCH 1/6] mmc: sdhci-esdhc-imx: remove redundant code for manual tuning haibo.chen
2021-08-16 12:38 ` [PATCH 2/6] mmc: sdhci-eadhc-imx: select the correct mode for auto tuning haibo.chen
2021-08-16 12:38 ` [PATCH 3/6] dt-bindings: mmc: fsl-imx-esdhc: add fsl, sdio-async-interrupt-enabled binding haibo.chen
2021-08-16 13:43 ` [PATCH 3/6] dt-bindings: mmc: fsl-imx-esdhc: add fsl,sdio-async-interrupt-enabled binding Ulf Hansson
2021-08-17 6:41 ` Bough Chen
2021-08-17 7:37 ` Ulf Hansson
2021-08-16 12:38 ` haibo.chen [this message]
2021-08-16 13:53 ` [PATCH 4/6] mmc: host: sdhci-esdhc-imx.c: correct the auto-tuning setting for sdio device Ulf Hansson
2021-08-17 6:57 ` Bough Chen
2021-08-17 8:00 ` Ulf Hansson
2021-08-17 12:29 ` Bough Chen
2021-08-16 12:38 ` [PATCH 5/6] arm64: dts: imx8mm-evk: add sdio wifi support haibo.chen
2021-08-16 12:38 ` [PATCH 6/6] arm64: dts: imx8mn-evk: " haibo.chen
2021-08-24 13:52 ` [PATCH 1/6] mmc: sdhci-esdhc-imx: remove redundant code for manual tuning Ulf Hansson
2021-08-25 2:16 ` Bough Chen
2021-08-25 9:22 ` Ulf Hansson
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