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From:   Faiz Abbas <faiz_abbas@ti.com>
To:     <linux-kernel@vger.kernel.org>, <linux-mmc@vger.kernel.org>
CC:     <ulf.hansson@linaro.org>, <kishon@ti.com>,
        <adrian.hunter@intel.com>, <faiz_abbas@ti.com>
Subject: [PATCH v2 2/3] mmc: sdhci-omap: Add platform specific reset callback
Date:   Wed, 21 Nov 2018 16:03:56 +0530
Message-ID: <20181121103357.3448-3-faiz_abbas@ti.com>
In-Reply-To: <20181121103357.3448-1-faiz_abbas@ti.com>
References: <20181121103357.3448-1-faiz_abbas@ti.com>
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The TRM (SPRUIC2C - January 2017 - Revised May 2018 [1]) forbids
assertion of data reset while tuning is happening. Implement a
platform specific callback that takes care of this condition.

[1] http://www.ti.com/lit/pdf/spruic2 Section 25.5.1.2.4

Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
---
 drivers/mmc/host/sdhci-omap.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
index d264391616f9..4fad47926743 100644
--- a/drivers/mmc/host/sdhci-omap.c
+++ b/drivers/mmc/host/sdhci-omap.c
@@ -115,6 +115,7 @@ struct sdhci_omap_host {
 
 	struct pinctrl		*pinctrl;
 	struct pinctrl_state	**pinctrl_state;
+	bool			is_tuning;
 };
 
 static void sdhci_omap_start_clock(struct sdhci_omap_host *omap_host);
@@ -322,6 +323,8 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
 		dcrc_was_enabled = true;
 	}
 
+	omap_host->is_tuning = true;
+
 	while (phase_delay <= MAX_PHASE_DELAY) {
 		sdhci_omap_set_dll(omap_host, phase_delay);
 
@@ -359,9 +362,12 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	phase_delay = max_window + 4 * (max_len >> 1);
 	sdhci_omap_set_dll(omap_host, phase_delay);
 
+	omap_host->is_tuning = false;
+
 	goto ret;
 
 tuning_error:
+	omap_host->is_tuning = false;
 	dev_err(dev, "Tuning failed\n");
 	sdhci_omap_disable_tuning(omap_host);
 
@@ -687,6 +693,18 @@ static void sdhci_omap_set_uhs_signaling(struct sdhci_host *host,
 	sdhci_omap_start_clock(omap_host);
 }
 
+void sdhci_omap_reset(struct sdhci_host *host, u8 mask)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
+
+	/* Don't reset data lines during tuning operation */
+	if (omap_host->is_tuning)
+		mask &= ~SDHCI_RESET_DATA;
+
+	sdhci_reset(host, mask);
+}
+
 static struct sdhci_ops sdhci_omap_ops = {
 	.set_clock = sdhci_omap_set_clock,
 	.set_power = sdhci_omap_set_power,
@@ -695,7 +713,7 @@ static struct sdhci_ops sdhci_omap_ops = {
 	.get_min_clock = sdhci_omap_get_min_clock,
 	.set_bus_width = sdhci_omap_set_bus_width,
 	.platform_send_init_74_clocks = sdhci_omap_init_74_clocks,
-	.reset = sdhci_reset,
+	.reset = sdhci_omap_reset,
 	.set_uhs_signaling = sdhci_omap_set_uhs_signaling,
 };
 
-- 
2.19.1