mtd: nand: sunxi: improve ->cmd_ctrl() function

Try to pack address and command cycles into a single NAND controller
command to avoid polling the status register for each single change
on the NAND bus.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
index e4d487cf2ebda12c4cdbd93f543d5be9fc19365a..ab572dd5ad3cb706f2b31e0e2b8869f88767f738 100644 (file)
--- a/drivers/mtd/nand/sunxi_nand.c
+++ b/drivers/mtd/nand/sunxi_nand.c
@@ -238,6 +238,10 @@ struct sunxi_nand_chip {
        u32 timing_cfg;
        u32 timing_ctl;
        int selected;
+       int addr_cycles;
+       u32 addr[2];
+       int cmd_cycles;
+       u8 cmd[2];
        int nsels;
        struct sunxi_nand_chip_sel sels[0];
 };
@@ -525,17 +529,49 @@ static void sunxi_nfc_cmd_ctrl(struct mtd_info *mtd, int dat,
                writel(tmp, nfc->regs + NFC_REG_CTL);
        }
 
-       if (dat == NAND_CMD_NONE)
-               return;
+       if (dat == NAND_CMD_NONE && (ctrl & NAND_NCE) &&
+           !(ctrl & (NAND_CLE | NAND_ALE))) {
+               u32 cmd = 0;
 
-       if (ctrl & NAND_CLE) {
-               writel(NFC_SEND_CMD1 | dat, nfc->regs + NFC_REG_CMD);
-       } else {
-               writel(dat, nfc->regs + NFC_REG_ADDR_LOW);
-               writel(NFC_SEND_ADR, nfc->regs + NFC_REG_CMD);
+               if (!sunxi_nand->addr_cycles && !sunxi_nand->cmd_cycles)
+                       return;
+
+               if (sunxi_nand->cmd_cycles--)
+                       cmd |= NFC_SEND_CMD1 | sunxi_nand->cmd[0];
+
+               if (sunxi_nand->cmd_cycles--) {
+                       cmd |= NFC_SEND_CMD2;
+                       writel(sunxi_nand->cmd[1],
+                              nfc->regs + NFC_REG_RCMD_SET);
+               }
+
+               sunxi_nand->cmd_cycles = 0;
+
+               if (sunxi_nand->addr_cycles) {
+                       cmd |= NFC_SEND_ADR |
+                              NFC_ADR_NUM(sunxi_nand->addr_cycles);
+                       writel(sunxi_nand->addr[0],
+                              nfc->regs + NFC_REG_ADDR_LOW);
+               }
+
+               if (sunxi_nand->addr_cycles > 4)
+                       writel(sunxi_nand->addr[1],
+                              nfc->regs + NFC_REG_ADDR_HIGH);
+
+               writel(cmd, nfc->regs + NFC_REG_CMD);
+               sunxi_nand->addr[0] = 0;
+               sunxi_nand->addr[1] = 0;
+               sunxi_nand->addr_cycles = 0;
+               sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
        }
 
-       sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
+       if (ctrl & NAND_CLE) {
+               sunxi_nand->cmd[sunxi_nand->cmd_cycles++] = dat;
+       } else if (ctrl & NAND_ALE) {
+               sunxi_nand->addr[sunxi_nand->addr_cycles / 4] |=
+                               dat << ((sunxi_nand->addr_cycles % 4) * 8);
+               sunxi_nand->addr_cycles++;
+       }
 }
 
 /* These seed values have been extracted from Allwinner's BSP */