[PATCH 08/16] mtd: nand: sunxi: improve ->cmd_ctrl() function

Boris Brezillon
2016-03-07T16:21:05Z

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>
---
drivers/mtd/nand/sunxi_nand.c | 52 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 44 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
index df73e55..db5446e 100644
--- a/drivers/mtd/nand/sunxi_nand.c
+++ b/drivers/mtd/nand/sunxi_nand.c
@@ -239,6 +239,10 @@ 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];
};
@@ -526,17 +530,49 @@ 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 */
--
2.1.4