linux-kernel - [PATCH AUTOSEL 4.19 037/101] mmc: sdhci: sdhci-pci-o2micro: Check if controller supports 8-bit width

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Message-Id: <20190719040732.17285-37-sashal@kernel.org>
Date:   Fri, 19 Jul 2019 00:06:28 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Raul E Rangel <rrangel@...omium.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Sasha Levin <sashal@...nel.org>, linux-mmc@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 037/101] mmc: sdhci: sdhci-pci-o2micro: Check if controller supports 8-bit width

From: Raul E Rangel <rrangel@...omium.org>

[ Upstream commit de23f0b757766d9fae59df97da6e8bdc5b231351 ]

The O2 controller supports 8-bit EMMC access.

JESD84-B51 section A.6.3.a defines the bus testing procedure that
`mmc_select_bus_width()` implements. This is used to determine the actual
bus width of the eMMC.

Signed-off-by: Raul E Rangel <rrangel@...omium.org>
Acked-by: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/mmc/host/sdhci-pci-o2micro.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
index fa8d9da2ab7f..e248d7945c06 100644
--- a/drivers/mmc/host/sdhci-pci-o2micro.c
+++ b/drivers/mmc/host/sdhci-pci-o2micro.c
@@ -290,11 +290,21 @@ int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
 {
 	struct sdhci_pci_chip *chip;
 	struct sdhci_host *host;
-	u32 reg;
+	u32 reg, caps;
 	int ret;
 
 	chip = slot->chip;
 	host = slot->host;
+
+	caps = sdhci_readl(host, SDHCI_CAPABILITIES);
+
+	/*
+	 * mmc_select_bus_width() will test the bus to determine the actual bus
+	 * width.
+	 */
+	if (caps & SDHCI_CAN_DO_8BIT)
+		host->mmc->caps |= MMC_CAP_8_BIT_DATA;
+
 	switch (chip->pdev->device) {
 	case PCI_DEVICE_ID_O2_SDS0:
 	case PCI_DEVICE_ID_O2_SEABIRD0:
-- 
2.20.1