mtd: lantiq: Add NAND support on Lantiq XWAY SoC.

The driver uses plat_nand. As the platform_device is loaded from DT, we need
to lookup the node and attach our xway specific "struct platform_nand_data"
to it.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

3 files changed, 210 insertions, 0 deletions

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 7101e8a03259..ce5cf020cd76 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -580,4 +580,12 @@ config MTD_NAND_FSMC
           Enables support for NAND Flash chips on the ST Microelectronics
           Flexible Static Memory Controller (FSMC)
 
+config MTD_NAND_XWAY
+        tristate "Support for NAND on Lantiq XWAY SoC"
+        depends on LANTIQ && SOC_TYPE_XWAY
+        select MTD_NAND_PLATFORM
+        help
+          Enables support for NAND Flash chips on Lantiq XWAY SoCs. NAND is attached
+          to the External Bus Unit (EBU).
+
 endif # MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index ddee81811b4a..c4b0ab316bab 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -53,5 +53,6 @@ obj-$(CONFIG_MTD_NAND_MPC5121_NFC)	+= mpc5121_nfc.o
 obj-$(CONFIG_MTD_NAND_RICOH)            += r852.o
 obj-$(CONFIG_MTD_NAND_JZ4740)           += jz4740_nand.o
 obj-$(CONFIG_MTD_NAND_GPMI_NAND)        += gpmi-nand/
+obj-$(CONFIG_MTD_NAND_XWAY)             += xway_nand.o
 
 nand-objs := nand_base.o nand_bbt.o
diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
new file mode 100644
index 000000000000..3f81dc8f214c
--- /dev/null
+++ b/drivers/mtd/nand/xway_nand.c
@@ -0,0 +1,201 @@
+/*
+ *  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.
+ *
+ *  Copyright © 2012 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/mtd/nand.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+
+#include <lantiq_soc.h>
+
+/* nand registers */
+#define EBU_ADDSEL1             0x24
+#define EBU_NAND_CON            0xB0
+#define EBU_NAND_WAIT           0xB4
+#define EBU_NAND_ECC0           0xB8
+#define EBU_NAND_ECC_AC         0xBC
+
+/* nand commands */
+#define NAND_CMD_ALE            (1 << 2)
+#define NAND_CMD_CLE            (1 << 3)
+#define NAND_CMD_CS             (1 << 4)
+#define NAND_WRITE_CMD_RESET    0xff
+#define NAND_WRITE_CMD          (NAND_CMD_CS | NAND_CMD_CLE)
+#define NAND_WRITE_ADDR         (NAND_CMD_CS | NAND_CMD_ALE)
+#define NAND_WRITE_DATA         (NAND_CMD_CS)
+#define NAND_READ_DATA          (NAND_CMD_CS)
+#define NAND_WAIT_WR_C          (1 << 3)
+#define NAND_WAIT_RD            (0x1)
+
+/* we need to tel the ebu which addr we mapped the nand to */
+#define ADDSEL1_MASK(x)         (x << 4)
+#define ADDSEL1_REGEN           1
+
+/* we need to tell the EBU that we have nand attached and set it up properly */
+#define BUSCON1_SETUP           (1 << 22)
+#define BUSCON1_BCGEN_RES       (0x3 << 12)
+#define BUSCON1_WAITWRC2        (2 << 8)
+#define BUSCON1_WAITRDC2        (2 << 6)
+#define BUSCON1_HOLDC1          (1 << 4)
+#define BUSCON1_RECOVC1         (1 << 2)
+#define BUSCON1_CMULT4          1
+
+#define NAND_CON_CE             (1 << 20)
+#define NAND_CON_OUT_CS1        (1 << 10)
+#define NAND_CON_IN_CS1         (1 << 8)
+#define NAND_CON_PRE_P          (1 << 7)
+#define NAND_CON_WP_P           (1 << 6)
+#define NAND_CON_SE_P           (1 << 5)
+#define NAND_CON_CS_P           (1 << 4)
+#define NAND_CON_CSMUX          (1 << 1)
+#define NAND_CON_NANDM          1
+
+static void xway_reset_chip(struct nand_chip *chip)
+{
+        unsigned long nandaddr = (unsigned long) chip->IO_ADDR_W;
+        unsigned long flags;
+
+        nandaddr &= ~NAND_WRITE_ADDR;
+        nandaddr |= NAND_WRITE_CMD;
+
+        /* finish with a reset */
+        spin_lock_irqsave(&ebu_lock, flags);
+        writeb(NAND_WRITE_CMD_RESET, (void __iomem *) nandaddr);
+        while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
+                ;
+        spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+static void xway_select_chip(struct mtd_info *mtd, int chip)
+{
+
+        switch (chip) {
+        case -1:
+                ltq_ebu_w32_mask(NAND_CON_CE, 0, EBU_NAND_CON);
+                ltq_ebu_w32_mask(NAND_CON_NANDM, 0, EBU_NAND_CON);
+                break;
+        case 0:
+                ltq_ebu_w32_mask(0, NAND_CON_NANDM, EBU_NAND_CON);
+                ltq_ebu_w32_mask(0, NAND_CON_CE, EBU_NAND_CON);
+                break;
+        default:
+                BUG();
+        }
+}
+
+static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
+{
+        struct nand_chip *this = mtd->priv;
+        unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
+        unsigned long flags;
+
+        if (ctrl & NAND_CTRL_CHANGE) {
+                nandaddr &= ~(NAND_WRITE_CMD | NAND_WRITE_ADDR);
+                if (ctrl & NAND_CLE)
+                        nandaddr |= NAND_WRITE_CMD;
+                else
+                        nandaddr |= NAND_WRITE_ADDR;
+                this->IO_ADDR_W = (void __iomem *) nandaddr;
+        }
+
+        if (cmd != NAND_CMD_NONE) {
+                spin_lock_irqsave(&ebu_lock, flags);
+                writeb(cmd, this->IO_ADDR_W);
+                while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
+                        ;
+                spin_unlock_irqrestore(&ebu_lock, flags);
+        }
+}
+
+static int xway_dev_ready(struct mtd_info *mtd)
+{
+        return ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_RD;
+}
+
+static unsigned char xway_read_byte(struct mtd_info *mtd)
+{
+        struct nand_chip *this = mtd->priv;
+        unsigned long nandaddr = (unsigned long) this->IO_ADDR_R;
+        unsigned long flags;
+        int ret;
+
+        spin_lock_irqsave(&ebu_lock, flags);
+        ret = ltq_r8((void __iomem *)(nandaddr + NAND_READ_DATA));
+        spin_unlock_irqrestore(&ebu_lock, flags);
+
+        return ret;
+}
+
+static int xway_nand_probe(struct platform_device *pdev)
+{
+        struct nand_chip *this = platform_get_drvdata(pdev);
+        unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
+        const __be32 *cs = of_get_property(pdev->dev.of_node,
+                                        "lantiq,cs", NULL);
+        u32 cs_flag = 0;
+
+        /* load our CS from the DT. Either we find a valid 1 or default to 0 */
+        if (cs && (*cs == 1))
+                cs_flag = NAND_CON_IN_CS1 | NAND_CON_OUT_CS1;
+
+        /* setup the EBU to run in NAND mode on our base addr */
+        ltq_ebu_w32(CPHYSADDR(nandaddr)
+                | ADDSEL1_MASK(3) | ADDSEL1_REGEN, EBU_ADDSEL1);
+
+        ltq_ebu_w32(BUSCON1_SETUP | BUSCON1_BCGEN_RES | BUSCON1_WAITWRC2
+                | BUSCON1_WAITRDC2 | BUSCON1_HOLDC1 | BUSCON1_RECOVC1
+                | BUSCON1_CMULT4, LTQ_EBU_BUSCON1);
+
+        ltq_ebu_w32(NAND_CON_NANDM | NAND_CON_CSMUX | NAND_CON_CS_P
+                | NAND_CON_SE_P | NAND_CON_WP_P | NAND_CON_PRE_P
+                | cs_flag, EBU_NAND_CON);
+
+        /* finish with a reset */
+        xway_reset_chip(this);
+
+        return 0;
+}
+
+/* allow users to override the partition in DT using the cmdline */
+static const char *part_probes[] = { "cmdlinepart", "ofpart", NULL };
+
+static struct platform_nand_data xway_nand_data = {
+        .chip = {
+                .nr_chips               = 1,
+                .chip_delay             = 30,
+                .part_probe_types       = part_probes,
+        },
+        .ctrl = {
+                .probe          = xway_nand_probe,
+                .cmd_ctrl       = xway_cmd_ctrl,
+                .dev_ready      = xway_dev_ready,
+                .select_chip    = xway_select_chip,
+                .read_byte      = xway_read_byte,
+        }
+};
+
+/*
+ * Try to find the node inside the DT. If it is available attach out
+ * platform_nand_data
+ */
+static int __init xway_register_nand(void)
+{
+        struct device_node *node;
+        struct platform_device *pdev;
+
+        node = of_find_compatible_node(NULL, NULL, "lantiq,nand-xway");
+        if (!node)
+                return -ENOENT;
+        pdev = of_find_device_by_node(node);
+        if (!pdev)
+                return -EINVAL;
+        pdev->dev.platform_data = &xway_nand_data;
+        of_node_put(node);
+        return 0;
+}
+
+subsys_initcall(xway_register_nand);