mtd: bcm47xxnflash: support for NAND_CMD_READID command

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

2 files changed, 106 insertions, 0 deletions

diff --git a/drivers/mtd/nand/bcm47xxnflash/bcm47xxnflash.h b/drivers/mtd/nand/bcm47xxnflash/bcm47xxnflash.h
index 2e8864a891e2..cc71400de116 100644
--- a/drivers/mtd/nand/bcm47xxnflash/bcm47xxnflash.h
+++ b/drivers/mtd/nand/bcm47xxnflash/bcm47xxnflash.h
@@ -9,6 +9,11 @@ struct bcm47xxnflash {
 
         struct nand_chip nand_chip;
         struct mtd_info mtd;
+
+        unsigned curr_command;
+        int curr_column;
+
+        u8 id_data[8];
 };
 
 #endif /* BCM47XXNFLASH */
diff --git a/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c b/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c
index ae8a79387c27..7de190e9a788 100644
--- a/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c
+++ b/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c
@@ -16,6 +16,10 @@
 
 #include "bcm47xxnflash.h"
 
+/* Broadcom uses 1'000'000 but it seems to be too many. Tests on WNDR4500 has
+ * shown 164 retries as maxiumum. */
+#define NFLASH_READY_RETRIES            1000
+
 /**************************************************
  * Various helpers
  **************************************************/
@@ -25,6 +29,24 @@ static inline u8 bcm47xxnflash_ops_bcm4706_ns_to_cycle(u16 ns, u16 clock)
         return ((ns * 1000 * clock) / 1000000) + 1;
 }
 
+static int bcm47xxnflash_ops_bcm4706_ctl_cmd(struct bcma_drv_cc *cc, u32 code)
+{
+        int i = 0;
+
+        bcma_cc_write32(cc, BCMA_CC_NFLASH_CTL, 0x80000000 | code);
+        for (i = 0; i < NFLASH_READY_RETRIES; i++) {
+                if (!(bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & 0x80000000)) {
+                        i = 0;
+                        break;
+                }
+        }
+        if (i) {
+                pr_err("NFLASH control command not ready!\n");
+                return -EBUSY;
+        }
+        return 0;
+}
+
 /**************************************************
  * NAND chip ops
  **************************************************/
@@ -36,6 +58,83 @@ static void bcm47xxnflash_ops_bcm4706_select_chip(struct mtd_info *mtd,
         return;
 }
 
+/*
+ * Default nand_command and nand_command_lp don't match BCM4706 hardware layout.
+ * For example, reading chip id is performed in a non-standard way.
+ * Setting column and page is also handled differently, we use a special
+ * registers of ChipCommon core. Hacking cmd_ctrl to understand and convert
+ * standard commands would be much more complicated.
+ */
+static void bcm47xxnflash_ops_bcm4706_cmdfunc(struct mtd_info *mtd,
+                                              unsigned command, int column,
+                                              int page_addr)
+{
+        struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
+        struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;
+        u32 ctlcode;
+        int i;
+
+        if (column != -1)
+                b47n->curr_column = column;
+
+        switch (command) {
+        case NAND_CMD_RESET:
+                pr_warn("Chip reset not implemented yet\n");
+                break;
+        case NAND_CMD_READID:
+                ctlcode = 0x40000000 | 0x01000000 | 0x00080000 | 0x00010000;
+                ctlcode |= NAND_CMD_READID;
+                if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode)) {
+                        pr_err("READID error\n");
+                        break;
+                }
+
+                /*
+                 * Reading is specific, last one has to go without 0x40000000
+                 * bit. We don't know how many reads NAND subsystem is going
+                 * to perform, so cache everything.
+                 */
+                for (i = 0; i < ARRAY_SIZE(b47n->id_data); i++) {
+                        ctlcode = 0x40000000 | 0x00100000;
+                        if (i == ARRAY_SIZE(b47n->id_data) - 1)
+                                ctlcode &= ~0x40000000;
+                        if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
+                                                              ctlcode)) {
+                                pr_err("READID error\n");
+                                break;
+                        }
+                        b47n->id_data[i] =
+                                bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA)
+                                & 0xFF;
+                }
+
+                break;
+        default:
+                pr_err("Command 0x%X unsupported\n", command);
+                break;
+        }
+        b47n->curr_command = command;
+}
+
+static u8 bcm47xxnflash_ops_bcm4706_read_byte(struct mtd_info *mtd)
+{
+        struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
+        struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;
+
+        switch (b47n->curr_command) {
+        case NAND_CMD_READID:
+                if (b47n->curr_column >= ARRAY_SIZE(b47n->id_data)) {
+                        pr_err("Requested invalid id_data: %d\n",
+                               b47n->curr_column);
+                        return 0;
+                }
+                return b47n->id_data[b47n->curr_column++];
+        }
+
+        pr_err("Invalid command for byte read: 0x%X\n", b47n->curr_command);
+        return 0;
+}
+
 /**************************************************
  * Init
  **************************************************/
@@ -52,6 +151,8 @@ int bcm47xxnflash_ops_bcm4706_init(struct bcm47xxnflash *b47n)
         u32 val;
 
         b47n->nand_chip.select_chip = bcm47xxnflash_ops_bcm4706_select_chip;
+        b47n->nand_chip.cmdfunc = bcm47xxnflash_ops_bcm4706_cmdfunc;
+        b47n->nand_chip.read_byte = bcm47xxnflash_ops_bcm4706_read_byte;
         b47n->nand_chip.ecc.mode = NAND_ECC_NONE; /* TODO: implement ECC */
 
         /* Enable NAND flash access */