sdhci-s3c: Samsung S3C based SDHCI controller glue

Add support for the 'HSMMC' block(s) in the Samsung SoC
line. These are compatible with the SDHCI driver so add
the necessary setup and driver binding for the platform
devices.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>

3 files changed, 451 insertions, 0 deletions

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 40111a6d8d5b..760992204a5e 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -94,6 +94,31 @@ config MMC_SDHCI_PLTFM
 
           If unsure, say N.
 
+config MMC_SDHCI_S3C
+        tristate "SDHCI support on Samsung S3C SoC"
+        depends on MMC_SDHCI && (PLAT_S3C24XX || PLAT_S3C64XX)
+        help
+          This selects the Secure Digital Host Controller Interface (SDHCI)
+          often referrered to as the HSMMC block in some of the Samsung S3C
+          range of SoC.
+
+          Note, due to the problems with DMA, the DMA support is only
+          available with CONFIG_EXPERIMENTAL is selected.
+
+          If you have a controller with this interface, say Y or M here.
+
+          If unsure, say N.
+
+config MMC_SDHCI_S3C_DMA
+        bool "DMA support on S3C SDHCI"
+        depends on MMC_SDHCI_S3C && EXPERIMENTAL
+        help
+          Enable DMA support on the Samsung S3C SDHCI glue. The DMA
+          has proved to be problematic if the controller encounters
+          certain errors, and thus should be treated with care.
+
+          YMMV.
+
 config MMC_OMAP
         tristate "TI OMAP Multimedia Card Interface support"
         depends on ARCH_OMAP
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 79da397c5fea..e637f2fa9bbd 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_MMC_SDHCI_PCI)	+= sdhci-pci.o
 obj-$(CONFIG_MMC_RICOH_MMC)     += ricoh_mmc.o
 obj-$(CONFIG_MMC_SDHCI_OF)      += sdhci-of.o
 obj-$(CONFIG_MMC_SDHCI_PLTFM)   += sdhci-pltfm.o
+obj-$(CONFIG_MMC_SDHCI_S3C)     += sdhci-s3c.o
 obj-$(CONFIG_MMC_WBSD)          += wbsd.o
 obj-$(CONFIG_MMC_AU1X)          += au1xmmc.o
 obj-$(CONFIG_MMC_OMAP)          += omap.o
diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
new file mode 100644
index 000000000000..19246fe3d3e2
--- /dev/null
+++ b/drivers/mmc/host/sdhci-s3c.c
@@ -0,0 +1,425 @@
+/* linux/drivers/mmc/host/sdhci-s3c.c
+ *
+ * Copyright 2008 Openmoko Inc.
+ * Copyright 2008 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *      http://armlinux.simtec.co.uk/
+ *
+ * SDHCI (HSMMC) support for Samsung SoC
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <linux/mmc/host.h>
+
+#include <plat/sdhci.h>
+#include <plat/regs-sdhci.h>
+
+#include "sdhci.h"
+
+#define MAX_BUS_CLK     (4)
+
+/**
+ * struct sdhci_s3c - S3C SDHCI instance
+ * @host: The SDHCI host created
+ * @pdev: The platform device we where created from.
+ * @ioarea: The resource created when we claimed the IO area.
+ * @pdata: The platform data for this controller.
+ * @cur_clk: The index of the current bus clock.
+ * @clk_io: The clock for the internal bus interface.
+ * @clk_bus: The clocks that are available for the SD/MMC bus clock.
+ */
+struct sdhci_s3c {
+        struct sdhci_host       *host;
+        struct platform_device  *pdev;
+        struct resource         *ioarea;
+        struct s3c_sdhci_platdata *pdata;
+        unsigned int            cur_clk;
+
+        struct clk              *clk_io;
+        struct clk              *clk_bus[MAX_BUS_CLK];
+};
+
+static inline struct sdhci_s3c *to_s3c(struct sdhci_host *host)
+{
+        return sdhci_priv(host);
+}
+
+/**
+ * get_curclk - convert ctrl2 register to clock source number
+ * @ctrl2: Control2 register value.
+ */
+static u32 get_curclk(u32 ctrl2)
+{
+        ctrl2 &= S3C_SDHCI_CTRL2_SELBASECLK_MASK;
+        ctrl2 >>= S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
+
+        return ctrl2;
+}
+
+static void sdhci_s3c_check_sclk(struct sdhci_host *host)
+{
+        struct sdhci_s3c *ourhost = to_s3c(host);
+        u32 tmp = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
+
+        if (get_curclk(tmp) != ourhost->cur_clk) {
+                dev_dbg(&ourhost->pdev->dev, "restored ctrl2 clock setting\n");
+
+                tmp &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
+                tmp |= ourhost->cur_clk << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
+                writel(tmp, host->ioaddr + 0x80);
+        }
+}
+
+/**
+ * sdhci_s3c_get_max_clk - callback to get maximum clock frequency.
+ * @host: The SDHCI host instance.
+ *
+ * Callback to return the maximum clock rate acheivable by the controller.
+*/
+static unsigned int sdhci_s3c_get_max_clk(struct sdhci_host *host)
+{
+        struct sdhci_s3c *ourhost = to_s3c(host);
+        struct clk *busclk;
+        unsigned int rate, max;
+        int clk;
+
+        /* note, a reset will reset the clock source */
+
+        sdhci_s3c_check_sclk(host);
+
+        for (max = 0, clk = 0; clk < MAX_BUS_CLK; clk++) {
+                busclk = ourhost->clk_bus[clk];
+                if (!busclk)
+                        continue;
+
+                rate = clk_get_rate(busclk);
+                if (rate > max)
+                        max = rate;
+        }
+
+        return max;
+}
+
+static unsigned int sdhci_s3c_get_timeout_clk(struct sdhci_host *host)
+{
+        return sdhci_s3c_get_max_clk(host) / 1000000;
+}
+
+/**
+ * sdhci_s3c_consider_clock - consider one the bus clocks for current setting
+ * @ourhost: Our SDHCI instance.
+ * @src: The source clock index.
+ * @wanted: The clock frequency wanted.
+ */
+static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
+                                             unsigned int src,
+                                             unsigned int wanted)
+{
+        unsigned long rate;
+        struct clk *clksrc = ourhost->clk_bus[src];
+        int div;
+
+        if (!clksrc)
+                return UINT_MAX;
+
+        rate = clk_get_rate(clksrc);
+
+        for (div = 1; div < 256; div *= 2) {
+                if ((rate / div) <= wanted)
+                        break;
+        }
+
+        dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
+                src, rate, wanted, rate / div);
+
+        return (wanted - (rate / div));
+}
+
+/**
+ * sdhci_s3c_set_clock - callback on clock change
+ * @host: The SDHCI host being changed
+ * @clock: The clock rate being requested.
+ *
+ * When the card's clock is going to be changed, look at the new frequency
+ * and find the best clock source to go with it.
+*/
+static void sdhci_s3c_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+        struct sdhci_s3c *ourhost = to_s3c(host);
+        unsigned int best = UINT_MAX;
+        unsigned int delta;
+        int best_src = 0;
+        int src;
+        u32 ctrl;
+
+        /* don't bother if the clock is going off. */
+        if (clock == 0)
+                return;
+
+        for (src = 0; src < MAX_BUS_CLK; src++) {
+                delta = sdhci_s3c_consider_clock(ourhost, src, clock);
+                if (delta < best) {
+                        best = delta;
+                        best_src = src;
+                }
+        }
+
+        dev_dbg(&ourhost->pdev->dev,
+                "selected source %d, clock %d, delta %d\n",
+                 best_src, clock, best);
+
+        /* select the new clock source */
+
+        if (ourhost->cur_clk != best_src) {
+                struct clk *clk = ourhost->clk_bus[best_src];
+
+                /* turn clock off to card before changing clock source */
+                writew(0, host->ioaddr + SDHCI_CLOCK_CONTROL);
+
+                ourhost->cur_clk = best_src;
+                host->max_clk = clk_get_rate(clk);
+                host->timeout_clk = sdhci_s3c_get_timeout_clk(host);
+
+                ctrl = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
+                ctrl &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
+                ctrl |= best_src << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
+                writel(ctrl, host->ioaddr + S3C_SDHCI_CONTROL2);
+        }
+
+        /* reconfigure the hardware for new clock rate */
+
+        {
+                struct mmc_ios ios;
+
+                ios.clock = clock;
+
+                if (ourhost->pdata->cfg_card)
+                        (ourhost->pdata->cfg_card)(ourhost->pdev, host->ioaddr,
+                                                   &ios, NULL);
+        }
+}
+
+static struct sdhci_ops sdhci_s3c_ops = {
+        .get_max_clock          = sdhci_s3c_get_max_clk,
+        .get_timeout_clock      = sdhci_s3c_get_timeout_clk,
+        .set_clock              = sdhci_s3c_set_clock,
+};
+
+static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
+{
+        struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;
+        struct device *dev = &pdev->dev;
+        struct sdhci_host *host;
+        struct sdhci_s3c *sc;
+        struct resource *res;
+        int ret, irq, ptr, clks;
+
+        if (!pdata) {
+                dev_err(dev, "no device data specified\n");
+                return -ENOENT;
+        }
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                dev_err(dev, "no irq specified\n");
+                return irq;
+        }
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(dev, "no memory specified\n");
+                return -ENOENT;
+        }
+
+        host = sdhci_alloc_host(dev, sizeof(struct sdhci_s3c));
+        if (IS_ERR(host)) {
+                dev_err(dev, "sdhci_alloc_host() failed\n");
+                return PTR_ERR(host);
+        }
+
+        sc = sdhci_priv(host);
+
+        sc->host = host;
+        sc->pdev = pdev;
+        sc->pdata = pdata;
+
+        platform_set_drvdata(pdev, host);
+
+        sc->clk_io = clk_get(dev, "hsmmc");
+        if (IS_ERR(sc->clk_io)) {
+                dev_err(dev, "failed to get io clock\n");
+                ret = PTR_ERR(sc->clk_io);
+                goto err_io_clk;
+        }
+
+        /* enable the local io clock and keep it running for the moment. */
+        clk_enable(sc->clk_io);
+
+        for (clks = 0, ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
+                struct clk *clk;
+                char *name = pdata->clocks[ptr];
+
+                if (name == NULL)
+                        continue;
+
+                clk = clk_get(dev, name);
+                if (IS_ERR(clk)) {
+                        dev_err(dev, "failed to get clock %s\n", name);
+                        continue;
+                }
+
+                clks++;
+                sc->clk_bus[ptr] = clk;
+                clk_enable(clk);
+
+                dev_info(dev, "clock source %d: %s (%ld Hz)\n",
+                         ptr, name, clk_get_rate(clk));
+        }
+
+        if (clks == 0) {
+                dev_err(dev, "failed to find any bus clocks\n");
+                ret = -ENOENT;
+                goto err_no_busclks;
+        }
+
+        sc->ioarea = request_mem_region(res->start, resource_size(res),
+                                        mmc_hostname(host->mmc));
+        if (!sc->ioarea) {
+                dev_err(dev, "failed to reserve register area\n");
+                ret = -ENXIO;
+                goto err_req_regs;
+        }
+
+        host->ioaddr = ioremap_nocache(res->start, resource_size(res));
+        if (!host->ioaddr) {
+                dev_err(dev, "failed to map registers\n");
+                ret = -ENXIO;
+                goto err_req_regs;
+        }
+
+        /* Ensure we have minimal gpio selected CMD/CLK/Detect */
+        if (pdata->cfg_gpio)
+                pdata->cfg_gpio(pdev, pdata->max_width);
+
+        host->hw_name = "samsung-hsmmc";
+        host->ops = &sdhci_s3c_ops;
+        host->quirks = 0;
+        host->irq = irq;
+
+        /* Setup quirks for the controller */
+
+        /* Currently with ADMA enabled we are getting some length
+         * interrupts that are not being dealt with, do disable
+         * ADMA until this is sorted out. */
+        host->quirks |= SDHCI_QUIRK_BROKEN_ADMA;
+        host->quirks |= SDHCI_QUIRK_32BIT_ADMA_SIZE;
+
+#ifndef CONFIG_MMC_SDHCI_S3C_DMA
+
+        /* we currently see overruns on errors, so disable the SDMA
+         * support as well. */
+        host->quirks |= SDHCI_QUIRK_BROKEN_DMA;
+
+#endif /* CONFIG_MMC_SDHCI_S3C_DMA */
+
+        /* It seems we do not get an DATA transfer complete on non-busy
+         * transfers, not sure if this is a problem with this specific
+         * SDHCI block, or a missing configuration that needs to be set. */
+        host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ;
+
+        host->quirks |= (SDHCI_QUIRK_32BIT_DMA_ADDR |
+                         SDHCI_QUIRK_32BIT_DMA_SIZE);
+
+        ret = sdhci_add_host(host);
+        if (ret) {
+                dev_err(dev, "sdhci_add_host() failed\n");
+                goto err_add_host;
+        }
+
+        return 0;
+
+ err_add_host:
+        release_resource(sc->ioarea);
+        kfree(sc->ioarea);
+
+ err_req_regs:
+        for (ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
+                clk_disable(sc->clk_bus[ptr]);
+                clk_put(sc->clk_bus[ptr]);
+        }
+
+ err_no_busclks:
+        clk_disable(sc->clk_io);
+        clk_put(sc->clk_io);
+
+ err_io_clk:
+        sdhci_free_host(host);
+
+        return ret;
+}
+
+static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
+{
+        return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int sdhci_s3c_suspend(struct platform_device *dev, pm_message_t pm)
+{
+        struct sdhci_host *host = platform_get_drvdata(dev);
+
+        sdhci_suspend_host(host, pm);
+        return 0;
+}
+
+static int sdhci_s3c_resume(struct platform_device *dev)
+{
+        struct sdhci_host *host = platform_get_drvdata(dev);
+
+        sdhci_resume_host(host);
+        return 0;
+}
+
+#else
+#define sdhci_s3c_suspend NULL
+#define sdhci_s3c_resume NULL
+#endif
+
+static struct platform_driver sdhci_s3c_driver = {
+        .probe          = sdhci_s3c_probe,
+        .remove         = __devexit_p(sdhci_s3c_remove),
+        .suspend        = sdhci_s3c_suspend,
+        .resume         = sdhci_s3c_resume,
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "s3c-sdhci",
+        },
+};
+
+static int __init sdhci_s3c_init(void)
+{
+        return platform_driver_register(&sdhci_s3c_driver);
+}
+
+static void __exit sdhci_s3c_exit(void)
+{
+        platform_driver_unregister(&sdhci_s3c_driver);
+}
+
+module_init(sdhci_s3c_init);
+module_exit(sdhci_s3c_exit);
+
+MODULE_DESCRIPTION("Samsung SDHCI (HSMMC) glue");
+MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:s3c-sdhci");