mtd: mxc_nand: add support for multiple chips on V21 devices

Do the following to add support for up to 4 chips on V21 devices (i.MX25 and
i.MX35):

* implement .select_chip for V21
* adjust existing NFC_V1_V2_BUF_ADDR writes to take chip select into account
* unlock all chip selects at preset_v1_v2()
* scan up to 4 devices at .probe

This has been tested on i.MX25 with two attached NAND chip (on one die).

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 32 insertions, 19 deletions

diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
index 42a95fb41504..b4efdb704ed2 100644
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -56,8 +56,14 @@
 #define NFC_V1_V2_WRPROT                (host->regs + 0x12)
 #define NFC_V1_UNLOCKSTART_BLKADDR      (host->regs + 0x14)
 #define NFC_V1_UNLOCKEND_BLKADDR        (host->regs + 0x16)
-#define NFC_V21_UNLOCKSTART_BLKADDR     (host->regs + 0x20)
-#define NFC_V21_UNLOCKEND_BLKADDR       (host->regs + 0x22)
+#define NFC_V21_UNLOCKSTART_BLKADDR0    (host->regs + 0x20)
+#define NFC_V21_UNLOCKSTART_BLKADDR1    (host->regs + 0x24)
+#define NFC_V21_UNLOCKSTART_BLKADDR2    (host->regs + 0x28)
+#define NFC_V21_UNLOCKSTART_BLKADDR3    (host->regs + 0x2c)
+#define NFC_V21_UNLOCKEND_BLKADDR0      (host->regs + 0x22)
+#define NFC_V21_UNLOCKEND_BLKADDR1      (host->regs + 0x26)
+#define NFC_V21_UNLOCKEND_BLKADDR2      (host->regs + 0x2a)
+#define NFC_V21_UNLOCKEND_BLKADDR3      (host->regs + 0x2e)
 #define NFC_V1_V2_NF_WRPRST             (host->regs + 0x18)
 #define NFC_V1_V2_CONFIG1               (host->regs + 0x1a)
 #define NFC_V1_V2_CONFIG2               (host->regs + 0x1c)
@@ -152,6 +158,7 @@ struct mxc_nand_host {
         int                     clk_act;
         int                     irq;
         int                     eccsize;
+        int                     active_cs;
 
         struct completion       op_completion;
 
@@ -445,7 +452,7 @@ static void send_page_v1_v2(struct mtd_info *mtd, unsigned int ops)
         for (i = 0; i < bufs; i++) {
 
                 /* NANDFC buffer 0 is used for page read/write */
-                writew(i, NFC_V1_V2_BUF_ADDR);
+                writew((host->active_cs << 4) | i, NFC_V1_V2_BUF_ADDR);
 
                 writew(ops, NFC_V1_V2_CONFIG2);
 
@@ -470,7 +477,7 @@ static void send_read_id_v1_v2(struct mxc_nand_host *host)
         struct nand_chip *this = &host->nand;
 
         /* NANDFC buffer 0 is used for device ID output */
-        writew(0x0, NFC_V1_V2_BUF_ADDR);
+        writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);
 
         writew(NFC_ID, NFC_V1_V2_CONFIG2);
 
@@ -505,7 +512,7 @@ static uint16_t get_dev_status_v1_v2(struct mxc_nand_host *host)
         uint32_t store;
         uint16_t ret;
 
-        writew(0x0, NFC_V1_V2_BUF_ADDR);
+        writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);
 
         /*
          * The device status is stored in main_area0. To
@@ -686,24 +693,24 @@ static void mxc_nand_select_chip(struct mtd_info *mtd, int chip)
         struct nand_chip *nand_chip = mtd->priv;
         struct mxc_nand_host *host = nand_chip->priv;
 
-        switch (chip) {
-        case -1:
+        if (chip == -1) {
                 /* Disable the NFC clock */
                 if (host->clk_act) {
                         clk_disable(host->clk);
                         host->clk_act = 0;
                 }
-                break;
-        case 0:
+                return;
+        }
+
+        if (!host->clk_act) {
                 /* Enable the NFC clock */
-                if (!host->clk_act) {
-                        clk_enable(host->clk);
-                        host->clk_act = 1;
-                }
-                break;
+                clk_enable(host->clk);
+                host->clk_act = 1;
+        }
 
-        default:
-                break;
+        if (nfc_is_v21()) {
+                host->active_cs = chip;
+                writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);
         }
 }
 
@@ -834,8 +841,14 @@ static void preset_v1_v2(struct mtd_info *mtd)
 
         /* Blocks to be unlocked */
         if (nfc_is_v21()) {
-                writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR);
-                writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR);
+                writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR0);
+                writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR1);
+                writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR2);
+                writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR3);
+                writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR0);
+                writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR1);
+                writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR2);
+                writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR3);
         } else if (nfc_is_v1()) {
                 writew(0x0, NFC_V1_UNLOCKSTART_BLKADDR);
                 writew(0x4000, NFC_V1_UNLOCKEND_BLKADDR);
@@ -1200,7 +1213,7 @@ static int __init mxcnd_probe(struct platform_device *pdev)
                 irq_control_v1_v2(host, 1);
 
         /* first scan to find the device and get the page size */
-        if (nand_scan_ident(mtd, 1, NULL)) {
+        if (nand_scan_ident(mtd, nfc_is_v21() ? 4 : 1, NULL)) {
                 err = -ENXIO;
                 goto escan;
         }