[PATCH v4 2/2] mtd: nand: raw: brcmnand: When oops in progress use pio and interrupt polling

[Kamal Dasu]

If mtd_oops is in progress, switch to polling during NAND command
completion instead of relying on DMA/interrupts so that the mtd_oops
buffer can be completely written in the assigned NAND partition.

Signed-off-by: Kamal Dasu <kdasu.k...@gmail.com>
---
 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 48 ++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c 
b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 8735277..27b22d6 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -151,6 +151,7 @@ struct brcmnand_controller {
        u32                     nand_cs_nand_xor;
        u32                     corr_stat_threshold;
        u32                     flash_dma_mode;
+       bool                    pio_poll_mode;
 };
 
 struct brcmnand_cfg {
@@ -815,6 +816,20 @@ static inline bool has_flash_dma(struct 
brcmnand_controller *ctrl)
        return ctrl->flash_dma_base;
 }
 
+static inline void disable_ctrl_irqs(struct brcmnand_controller *ctrl)
+{
+       if (ctrl->pio_poll_mode)
+               return;
+
+       if (has_flash_dma(ctrl)) {
+               ctrl->flash_dma_base = 0;
+               disable_irq(ctrl->dma_irq);
+       }
+
+       disable_irq(ctrl->irq);
+       ctrl->pio_poll_mode = true;
+}
+
 static inline bool flash_dma_buf_ok(const void *buf)
 {
        return buf && !is_vmalloc_addr(buf) &&
@@ -1229,15 +1244,42 @@ static void brcmnand_cmd_ctrl(struct nand_chip *chip, 
int dat,
        /* intentionally left blank */
 }
 
+static bool brcmstb_nand_wait_for_completion(struct nand_chip *chip)
+{
+       struct brcmnand_host *host = nand_get_controller_data(chip);
+       struct brcmnand_controller *ctrl = host->ctrl;
+       struct mtd_info *mtd = nand_to_mtd(chip);
+       bool err = false;
+       int sts;
+
+       if (mtd->panic_write_triggered) {
+               /* switch to interrupt polling and PIO mode */
+               disable_ctrl_irqs(ctrl);
+               sts = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY,
+                                              NAND_CTRL_RDY, 0);
+               err = (sts < 0) ? true : false;
+       } else {
+               unsigned long timeo = msecs_to_jiffies(
+                                               NAND_POLL_STATUS_TIMEOUT_MS);
+               /* wait for completion interrupt */
+               sts = wait_for_completion_timeout(&ctrl->done, timeo);
+               err = (sts <= 0) ? true : false;
+       }
+
+       return err;
+}
+
 static int brcmnand_waitfunc(struct nand_chip *chip)
 {
        struct brcmnand_host *host = nand_get_controller_data(chip);
        struct brcmnand_controller *ctrl = host->ctrl;
-       unsigned long timeo = msecs_to_jiffies(100);
+       bool err = false;
 
        dev_dbg(ctrl->dev, "wait on native cmd %d\n", ctrl->cmd_pending);
-       if (ctrl->cmd_pending &&
-                       wait_for_completion_timeout(&ctrl->done, timeo) <= 0) {
+       if (ctrl->cmd_pending)
+               err = brcmstb_nand_wait_for_completion(chip);
+
+       if (err) {
                u32 cmd = brcmnand_read_reg(ctrl, BRCMNAND_CMD_START)
                                        >> brcmnand_cmd_shift(ctrl);
 
-- 
1.9.0.138.g2de3478