MTD: NAND: JZ4740: Multi-bank support with autodetection

The platform data can now specify which external memory banks to probe
for NAND chips, and in which order. Banks that contain a NAND are used
and the other banks are freed.

Squashed version of development done in jz-2.6.38 branch.
Original patch by Lars-Peter Clausen with some bug fixes from me.
Thanks to Paul Cercueil for the initial autodetection patch.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3560/
Acked-By: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 192 insertions, 36 deletions

diff --git a/drivers/mtd/nand/jz4740_nand.c b/drivers/mtd/nand/jz4740_nand.c
index a6fa884ae49b..100b6775e175 100644
--- a/drivers/mtd/nand/jz4740_nand.c
+++ b/drivers/mtd/nand/jz4740_nand.c
@@ -52,9 +52,10 @@
 
 #define JZ_NAND_CTRL_ENABLE_CHIP(x) BIT((x) << 1)
 #define JZ_NAND_CTRL_ASSERT_CHIP(x) BIT(((x) << 1) + 1)
+#define JZ_NAND_CTRL_ASSERT_CHIP_MASK 0xaa
 
-#define JZ_NAND_MEM_ADDR_OFFSET 0x10000
 #define JZ_NAND_MEM_CMD_OFFSET 0x08000
+#define JZ_NAND_MEM_ADDR_OFFSET 0x10000
 
 struct jz_nand {
         struct mtd_info mtd;
@@ -62,8 +63,11 @@ struct jz_nand {
         void __iomem *base;
         struct resource *mem;
 
-        void __iomem *bank_base;
-        struct resource *bank_mem;
+        unsigned char banks[JZ_NAND_NUM_BANKS];
+        void __iomem *bank_base[JZ_NAND_NUM_BANKS];
+        struct resource *bank_mem[JZ_NAND_NUM_BANKS];
+
+        int selected_bank;
 
         struct jz_nand_platform_data *pdata;
         bool is_reading;
@@ -74,26 +78,50 @@ static inline struct jz_nand *mtd_to_jz_nand(struct mtd_info *mtd)
         return container_of(mtd, struct jz_nand, mtd);
 }
 
+static void jz_nand_select_chip(struct mtd_info *mtd, int chipnr)
+{
+        struct jz_nand *nand = mtd_to_jz_nand(mtd);
+        struct nand_chip *chip = mtd->priv;
+        uint32_t ctrl;
+        int banknr;
+
+        ctrl = readl(nand->base + JZ_REG_NAND_CTRL);
+        ctrl &= ~JZ_NAND_CTRL_ASSERT_CHIP_MASK;
+
+        if (chipnr == -1) {
+                banknr = -1;
+        } else {
+                banknr = nand->banks[chipnr] - 1;
+                chip->IO_ADDR_R = nand->bank_base[banknr];
+                chip->IO_ADDR_W = nand->bank_base[banknr];
+        }
+        writel(ctrl, nand->base + JZ_REG_NAND_CTRL);
+
+        nand->selected_bank = banknr;
+}
+
 static void jz_nand_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)
 {
         struct jz_nand *nand = mtd_to_jz_nand(mtd);
         struct nand_chip *chip = mtd->priv;
         uint32_t reg;
+        void __iomem *bank_base = nand->bank_base[nand->selected_bank];
+
+        BUG_ON(nand->selected_bank < 0);
 
         if (ctrl & NAND_CTRL_CHANGE) {
                 BUG_ON((ctrl & NAND_ALE) && (ctrl & NAND_CLE));
                 if (ctrl & NAND_ALE)
-                        chip->IO_ADDR_W = nand->bank_base + JZ_NAND_MEM_ADDR_OFFSET;
+                        bank_base += JZ_NAND_MEM_ADDR_OFFSET;
                 else if (ctrl & NAND_CLE)
-                        chip->IO_ADDR_W = nand->bank_base + JZ_NAND_MEM_CMD_OFFSET;
-                else
-                        chip->IO_ADDR_W = nand->bank_base;
+                        bank_base += JZ_NAND_MEM_CMD_OFFSET;
+                chip->IO_ADDR_W = bank_base;
 
                 reg = readl(nand->base + JZ_REG_NAND_CTRL);
                 if (ctrl & NAND_NCE)
-                        reg |= JZ_NAND_CTRL_ASSERT_CHIP(0);
+                        reg |= JZ_NAND_CTRL_ASSERT_CHIP(nand->selected_bank);
                 else
-                        reg &= ~JZ_NAND_CTRL_ASSERT_CHIP(0);
+                        reg &= ~JZ_NAND_CTRL_ASSERT_CHIP(nand->selected_bank);
                 writel(reg, nand->base + JZ_REG_NAND_CTRL);
         }
         if (dat != NAND_CMD_NONE)
@@ -252,7 +280,7 @@ static int jz_nand_correct_ecc_rs(struct mtd_info *mtd, uint8_t *dat,
 }
 
 static int jz_nand_ioremap_resource(struct platform_device *pdev,
-        const char *name, struct resource **res, void __iomem **base)
+        const char *name, struct resource **res, void *__iomem *base)
 {
         int ret;
 
@@ -288,6 +316,90 @@ err:
         return ret;
 }
 
+static inline void jz_nand_iounmap_resource(struct resource *res, void __iomem *base)
+{
+        iounmap(base);
+        release_mem_region(res->start, resource_size(res));
+}
+
+static int __devinit jz_nand_detect_bank(struct platform_device *pdev, struct jz_nand *nand, unsigned char bank, size_t chipnr, uint8_t *nand_maf_id, uint8_t *nand_dev_id) {
+        int ret;
+        int gpio;
+        char gpio_name[9];
+        char res_name[6];
+        uint32_t ctrl;
+        struct mtd_info *mtd = &nand->mtd;
+        struct nand_chip *chip = &nand->chip;
+
+        /* Request GPIO port. */
+        gpio = JZ_GPIO_MEM_CS0 + bank - 1;
+        sprintf(gpio_name, "NAND CS%d", bank);
+        ret = gpio_request(gpio, gpio_name);
+        if (ret) {
+                dev_warn(&pdev->dev,
+                        "Failed to request %s gpio %d: %d\n",
+                        gpio_name, gpio, ret);
+                goto notfound_gpio;
+        }
+
+        /* Request I/O resource. */
+        sprintf(res_name, "bank%d", bank);
+        ret = jz_nand_ioremap_resource(pdev, res_name,
+                                        &nand->bank_mem[bank - 1],
+                                        &nand->bank_base[bank - 1]);
+        if (ret)
+                goto notfound_resource;
+
+        /* Enable chip in bank. */
+        jz_gpio_set_function(gpio, JZ_GPIO_FUNC_MEM_CS0);
+        ctrl = readl(nand->base + JZ_REG_NAND_CTRL);
+        ctrl |= JZ_NAND_CTRL_ENABLE_CHIP(bank - 1);
+        writel(ctrl, nand->base + JZ_REG_NAND_CTRL);
+
+        if (chipnr == 0) {
+                /* Detect first chip. */
+                ret = nand_scan_ident(mtd, 1, NULL);
+                if (ret)
+                        goto notfound_id;
+
+                /* Retrieve the IDs from the first chip. */
+                chip->select_chip(mtd, 0);
+                chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+                chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
+                *nand_maf_id = chip->read_byte(mtd);
+                *nand_dev_id = chip->read_byte(mtd);
+        } else {
+                /* Detect additional chip. */
+                chip->select_chip(mtd, chipnr);
+                chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+                chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
+                if (*nand_maf_id != chip->read_byte(mtd)
+                 || *nand_dev_id != chip->read_byte(mtd)) {
+                        ret = -ENODEV;
+                        goto notfound_id;
+                }
+
+                /* Update size of the MTD. */
+                chip->numchips++;
+                mtd->size += chip->chipsize;
+        }
+
+        dev_info(&pdev->dev, "Found chip %i on bank %i\n", chipnr, bank);
+        return 0;
+
+notfound_id:
+        dev_info(&pdev->dev, "No chip found on bank %i\n", bank);
+        ctrl &= ~(JZ_NAND_CTRL_ENABLE_CHIP(bank - 1));
+        writel(ctrl, nand->base + JZ_REG_NAND_CTRL);
+        jz_gpio_set_function(gpio, JZ_GPIO_FUNC_NONE);
+        jz_nand_iounmap_resource(nand->bank_mem[bank - 1],
+                                 nand->bank_base[bank - 1]);
+notfound_resource:
+        gpio_free(gpio);
+notfound_gpio:
+        return ret;
+}
+
 static int __devinit jz_nand_probe(struct platform_device *pdev)
 {
         int ret;
@@ -295,6 +407,8 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
         struct nand_chip *chip;
         struct mtd_info *mtd;
         struct jz_nand_platform_data *pdata = pdev->dev.platform_data;
+        size_t chipnr, bank_idx;
+        uint8_t nand_maf_id = 0, nand_dev_id = 0;
 
         nand = kzalloc(sizeof(*nand), GFP_KERNEL);
         if (!nand) {
@@ -305,10 +419,6 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
         ret = jz_nand_ioremap_resource(pdev, "mmio", &nand->mem, &nand->base);
         if (ret)
                 goto err_free;
-        ret = jz_nand_ioremap_resource(pdev, "bank", &nand->bank_mem,
-                        &nand->bank_base);
-        if (ret)
-                goto err_iounmap_mmio;
 
         if (pdata && gpio_is_valid(pdata->busy_gpio)) {
                 ret = gpio_request(pdata->busy_gpio, "NAND busy pin");
@@ -316,7 +426,7 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
                         dev_err(&pdev->dev,
                                 "Failed to request busy gpio %d: %d\n",
                                 pdata->busy_gpio, ret);
-                        goto err_iounmap_mem;
+                        goto err_iounmap_mmio;
                 }
         }
 
@@ -339,22 +449,51 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
 
         chip->chip_delay = 50;
         chip->cmd_ctrl = jz_nand_cmd_ctrl;
+        chip->select_chip = jz_nand_select_chip;
 
         if (pdata && gpio_is_valid(pdata->busy_gpio))
                 chip->dev_ready = jz_nand_dev_ready;
 
-        chip->IO_ADDR_R = nand->bank_base;
-        chip->IO_ADDR_W = nand->bank_base;
-
         nand->pdata = pdata;
         platform_set_drvdata(pdev, nand);
 
-        writel(JZ_NAND_CTRL_ENABLE_CHIP(0), nand->base + JZ_REG_NAND_CTRL);
-
-        ret = nand_scan_ident(mtd, 1, NULL);
-        if (ret) {
-                dev_err(&pdev->dev,  "Failed to scan nand\n");
-                goto err_gpio_free;
+        /* We are going to autodetect NAND chips in the banks specified in the
+         * platform data. Although nand_scan_ident() can detect multiple chips,
+         * it requires those chips to be numbered consecuitively, which is not
+         * always the case for external memory banks. And a fixed chip-to-bank
+         * mapping is not practical either, since for example Dingoo units
+         * produced at different times have NAND chips in different banks.
+         */
+        chipnr = 0;
+        for (bank_idx = 0; bank_idx < JZ_NAND_NUM_BANKS; bank_idx++) {
+                unsigned char bank;
+
+                /* If there is no platform data, look for NAND in bank 1,
+                 * which is the most likely bank since it is the only one
+                 * that can be booted from.
+                 */
+                bank = pdata ? pdata->banks[bank_idx] : bank_idx ^ 1;
+                if (bank == 0)
+                        break;
+                if (bank > JZ_NAND_NUM_BANKS) {
+                        dev_warn(&pdev->dev,
+                                "Skipping non-existing bank: %d\n", bank);
+                        continue;
+                }
+                /* The detection routine will directly or indirectly call
+                 * jz_nand_select_chip(), so nand->banks has to contain the
+                 * bank we're checking.
+                 */
+                nand->banks[chipnr] = bank;
+                if (jz_nand_detect_bank(pdev, nand, bank, chipnr,
+                                        &nand_maf_id, &nand_dev_id) == 0)
+                        chipnr++;
+                else
+                        nand->banks[chipnr] = 0;
+        }
+        if (chipnr == 0) {
+                dev_err(&pdev->dev, "No NAND chips found\n");
+                goto err_gpio_busy;
         }
 
         if (pdata && pdata->ident_callback) {
@@ -364,8 +503,8 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
 
         ret = nand_scan_tail(mtd);
         if (ret) {
-                dev_err(&pdev->dev,  "Failed to scan nand\n");
-                goto err_gpio_free;
+                dev_err(&pdev->dev,  "Failed to scan NAND\n");
+                goto err_unclaim_banks;
         }
 
         ret = mtd_device_parse_register(mtd, NULL, NULL,
@@ -382,14 +521,21 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
         return 0;
 
 err_nand_release:
-        nand_release(&nand->mtd);
-err_gpio_free:
+        nand_release(mtd);
+err_unclaim_banks:
+        while (chipnr--) {
+                unsigned char bank = nand->banks[chipnr];
+                gpio_free(JZ_GPIO_MEM_CS0 + bank - 1);
+                jz_nand_iounmap_resource(nand->bank_mem[bank - 1],
+                                         nand->bank_base[bank - 1]);
+        }
+        writel(0, nand->base + JZ_REG_NAND_CTRL);
+err_gpio_busy:
+        if (pdata && gpio_is_valid(pdata->busy_gpio))
+                gpio_free(pdata->busy_gpio);
         platform_set_drvdata(pdev, NULL);
-        gpio_free(pdata->busy_gpio);
-err_iounmap_mem:
-        iounmap(nand->bank_base);
 err_iounmap_mmio:
-        iounmap(nand->base);
+        jz_nand_iounmap_resource(nand->mem, nand->base);
 err_free:
         kfree(nand);
         return ret;
@@ -398,16 +544,26 @@ err_free:
 static int __devexit jz_nand_remove(struct platform_device *pdev)
 {
         struct jz_nand *nand = platform_get_drvdata(pdev);
+        struct jz_nand_platform_data *pdata = pdev->dev.platform_data;
+        size_t i;
 
         nand_release(&nand->mtd);
 
         /* Deassert and disable all chips */
         writel(0, nand->base + JZ_REG_NAND_CTRL);
 
-        iounmap(nand->bank_base);
-        release_mem_region(nand->bank_mem->start, resource_size(nand->bank_mem));
-        iounmap(nand->base);
-        release_mem_region(nand->mem->start, resource_size(nand->mem));
+        for (i = 0; i < JZ_NAND_NUM_BANKS; ++i) {
+                unsigned char bank = nand->banks[i];
+                if (bank != 0) {
+                        jz_nand_iounmap_resource(nand->bank_mem[bank - 1],
+                                                 nand->bank_base[bank - 1]);
+                        gpio_free(JZ_GPIO_MEM_CS0 + bank - 1);
+                }
+        }
+        if (pdata && gpio_is_valid(pdata->busy_gpio))
+                gpio_free(pdata->busy_gpio);
+
+        jz_nand_iounmap_resource(nand->mem, nand->base);
 
         platform_set_drvdata(pdev, NULL);
         kfree(nand);