mmc: add sdhci-tegra driver for Tegra SoCs

SDHCI driver for Tegra. This driver plugs in as a new variant of
sdhci-pltfm, using the platform data structure passed in to specify the
GPIOs to use for card detect, write protect and card power enablement.

Original driver (of which only the header file is left):
Signed-off-by: Yvonne Yip <y@palm.com>

The rest, which has been rewritten by now:
Signed-off-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 257 insertions, 0 deletions

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
new file mode 100644
index 000000000000..4823ee94a63f
--- /dev/null
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -0,0 +1,257 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
+
+#include <mach/gpio.h>
+#include <mach/sdhci.h>
+
+#include "sdhci.h"
+#include "sdhci-pltfm.h"
+
+static u32 tegra_sdhci_readl(struct sdhci_host *host, int reg)
+{
+	u32 val;
+
+	if (unlikely(reg == SDHCI_PRESENT_STATE)) {
+		/* Use wp_gpio here instead? */
+		val = readl(host->ioaddr + reg);
+		return val | SDHCI_WRITE_PROTECT;
+	}
+
+	return readl(host->ioaddr + reg);
+}
+
+static u16 tegra_sdhci_readw(struct sdhci_host *host, int reg)
+{
+	if (unlikely(reg == SDHCI_HOST_VERSION)) {
+		/* Erratum: Version register is invalid in HW. */
+		return SDHCI_SPEC_200;
+	}
+
+	return readw(host->ioaddr + reg);
+}
+
+static void tegra_sdhci_writel(struct sdhci_host *host, u32 val, int reg)
+{
+	/* Seems like we're getting spurious timeout and crc errors, so
+	 * disable signalling of them. In case of real errors software
+	 * timers should take care of eventually detecting them.
+	 */
+	if (unlikely(reg == SDHCI_SIGNAL_ENABLE))
+		val &= ~(SDHCI_INT_TIMEOUT|SDHCI_INT_CRC);
+
+	writel(val, host->ioaddr + reg);
+
+	if (unlikely(reg == SDHCI_INT_ENABLE)) {
+		/* Erratum: Must enable block gap interrupt detection */
+		u8 gap_ctrl = readb(host->ioaddr + SDHCI_BLOCK_GAP_CONTROL);
+		if (val & SDHCI_INT_CARD_INT)
+			gap_ctrl |= 0x8;
+		else
+			gap_ctrl &= ~0x8;
+		writeb(gap_ctrl, host->ioaddr + SDHCI_BLOCK_GAP_CONTROL);
+	}
+}
+
+static unsigned int tegra_sdhci_get_ro(struct sdhci_host *sdhci)
+{
+	struct platform_device *pdev = to_platform_device(mmc_dev(sdhci->mmc));
+	struct tegra_sdhci_platform_data *plat;
+
+	plat = pdev->dev.platform_data;
+
+	if (!gpio_is_valid(plat->wp_gpio))
+		return -1;
+
+	return gpio_get_value(plat->wp_gpio);
+}
+
+static irqreturn_t carddetect_irq(int irq, void *data)
+{
+	struct sdhci_host *sdhost = (struct sdhci_host *)data;
+
+	tasklet_schedule(&sdhost->card_tasklet);
+	return IRQ_HANDLED;
+};
+
+static int tegra_sdhci_8bit(struct sdhci_host *host, int bus_width)
+{
+	struct platform_device *pdev = to_platform_device(mmc_dev(host->mmc));
+	struct tegra_sdhci_platform_data *plat;
+	u32 ctrl;
+
+	plat = pdev->dev.platform_data;
+
+	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
+	if (plat->is_8bit && bus_width == MMC_BUS_WIDTH_8) {
+		ctrl &= ~SDHCI_CTRL_4BITBUS;
+		ctrl |= SDHCI_CTRL_8BITBUS;
+	} else {
+		ctrl &= ~SDHCI_CTRL_8BITBUS;
+		if (bus_width == MMC_BUS_WIDTH_4)
+			ctrl |= SDHCI_CTRL_4BITBUS;
+		else
+			ctrl &= ~SDHCI_CTRL_4BITBUS;
+	}
+	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+	return 0;
+}
+
+
+static int tegra_sdhci_pltfm_init(struct sdhci_host *host,
+				  struct sdhci_pltfm_data *pdata)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct platform_device *pdev = to_platform_device(mmc_dev(host->mmc));
+	struct tegra_sdhci_platform_data *plat;
+	struct clk *clk;
+	int rc;
+
+	plat = pdev->dev.platform_data;
+	if (plat == NULL) {
+		dev_err(mmc_dev(host->mmc), "missing platform data\n");
+		return -ENXIO;
+	}
+
+	if (gpio_is_valid(plat->power_gpio)) {
+		rc = gpio_request(plat->power_gpio, "sdhci_power");
+		if (rc) {
+			dev_err(mmc_dev(host->mmc),
+				"failed to allocate power gpio\n");
+			goto out;
+		}
+		tegra_gpio_enable(plat->power_gpio);
+		gpio_direction_output(plat->power_gpio, 1);
+	}
+
+	if (gpio_is_valid(plat->cd_gpio)) {
+		rc = gpio_request(plat->cd_gpio, "sdhci_cd");
+		if (rc) {
+			dev_err(mmc_dev(host->mmc),
+				"failed to allocate cd gpio\n");
+			goto out_power;
+		}
+		tegra_gpio_enable(plat->cd_gpio);
+		gpio_direction_input(plat->cd_gpio);
+
+		rc = request_irq(gpio_to_irq(plat->cd_gpio), carddetect_irq,
+				 IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+				 mmc_hostname(host->mmc), host);
+
+		if (rc)	{
+			dev_err(mmc_dev(host->mmc), "request irq error\n");
+			goto out_cd;
+		}
+
+	}
+
+	if (gpio_is_valid(plat->wp_gpio)) {
+		rc = gpio_request(plat->wp_gpio, "sdhci_wp");
+		if (rc) {
+			dev_err(mmc_dev(host->mmc),
+				"failed to allocate wp gpio\n");
+			goto out_cd;
+		}
+		tegra_gpio_enable(plat->wp_gpio);
+		gpio_direction_input(plat->wp_gpio);
+	}
+
+	clk = clk_get(mmc_dev(host->mmc), NULL);
+	if (IS_ERR(clk)) {
+		dev_err(mmc_dev(host->mmc), "clk err\n");
+		rc = PTR_ERR(clk);
+		goto out_wp;
+	}
+	clk_enable(clk);
+	pltfm_host->clk = clk;
+
+	if (plat->is_8bit)
+		host->mmc->caps |= MMC_CAP_8_BIT_DATA;
+
+	return 0;
+
+out_wp:
+	if (gpio_is_valid(plat->wp_gpio)) {
+		tegra_gpio_disable(plat->wp_gpio);
+		gpio_free(plat->wp_gpio);
+	}
+
+out_cd:
+	if (gpio_is_valid(plat->cd_gpio)) {
+		tegra_gpio_disable(plat->cd_gpio);
+		gpio_free(plat->cd_gpio);
+	}
+
+out_power:
+	if (gpio_is_valid(plat->power_gpio)) {
+		tegra_gpio_disable(plat->power_gpio);
+		gpio_free(plat->power_gpio);
+	}
+
+out:
+	return rc;
+}
+
+static void tegra_sdhci_pltfm_exit(struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct platform_device *pdev = to_platform_device(mmc_dev(host->mmc));
+	struct tegra_sdhci_platform_data *plat;
+
+	plat = pdev->dev.platform_data;
+
+	if (gpio_is_valid(plat->wp_gpio)) {
+		tegra_gpio_disable(plat->wp_gpio);
+		gpio_free(plat->wp_gpio);
+	}
+
+	if (gpio_is_valid(plat->cd_gpio)) {
+		tegra_gpio_disable(plat->cd_gpio);
+		gpio_free(plat->cd_gpio);
+	}
+
+	if (gpio_is_valid(plat->power_gpio)) {
+		tegra_gpio_disable(plat->power_gpio);
+		gpio_free(plat->power_gpio);
+	}
+
+	clk_disable(pltfm_host->clk);
+	clk_put(pltfm_host->clk);
+}
+
+static struct sdhci_ops tegra_sdhci_ops = {
+	.get_ro     = tegra_sdhci_get_ro,
+	.read_l     = tegra_sdhci_readl,
+	.read_w     = tegra_sdhci_readw,
+	.write_l    = tegra_sdhci_writel,
+	.platform_8bit_width = tegra_sdhci_8bit,
+};
+
+struct sdhci_pltfm_data sdhci_tegra_pdata = {
+	.quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
+		  SDHCI_QUIRK_SINGLE_POWER_WRITE |
+		  SDHCI_QUIRK_NO_HISPD_BIT |
+		  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC,
+	.ops  = &tegra_sdhci_ops,
+	.init = tegra_sdhci_pltfm_init,
+	.exit = tegra_sdhci_pltfm_exit,
+};