[PATCH 2/2] mtd: atmel_nand: NFC: support multiple interrupt handling

[Josh Wu]

It fixes following error sometime happens during the NFC data transfer:
  atmel_nand 80000000.nand: Time out to wait for interrupt: 0x00010000
  atmel_nand 80000000.nand: something wrong, No XFR_DONE interrupt comes.

The root cause is in current interrupt handler, we read the ISR but
only handle one interrupt. If there are more than one interrupt come
together, then the second one will be lost.

During the NFC data transfer. There is possible two NFC interrupts:
NFC_CMD_DONE and NFC_XFR_DONE, come in same time.

NFC_CMD_DONE means NFC command is send. and NFC_XFR_DONE means NFC data
is transfered.

This patch can handle multiple NFC interrupts in same time. And during
the NFC data transfer, we need to wait for two NFC interrupts:
NFC_CMD_DONE and NFC_XFR_DONE.

Reported-by: Matthieu CRAPET <Matthieu.CRAPET at ingenico.com>
Signed-off-by: Josh Wu <josh.wu at atmel.com>
---
 drivers/mtd/nand/atmel_nand.c |   61 +++++++++++++++++++++++------------------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 347cee2..faee53d 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -1579,7 +1579,7 @@ static irqreturn_t hsmc_interrupt(int irq, void *dev_id)
 {
 	struct atmel_nand_host *host = dev_id;
 	u32 status, mask, pending;
-	irqreturn_t ret = IRQ_HANDLED;
+	irqreturn_t ret = IRQ_NONE;
 
 	status = nfc_readl(host->nfc->hsmc_regs, SR);
 	mask = nfc_readl(host->nfc->hsmc_regs, IMR);
@@ -1588,14 +1588,17 @@ static irqreturn_t hsmc_interrupt(int irq, void *dev_id)
 	if (pending & NFC_SR_XFR_DONE) {
 		complete(&host->nfc->comp_xfer_done);
 		nfc_writel(host->nfc->hsmc_regs, IDR, NFC_SR_XFR_DONE);
-	} else if (pending & NFC_SR_RB_EDGE) {
+		ret = IRQ_HANDLED;
+	}
+	if (pending & NFC_SR_RB_EDGE) {
 		complete(&host->nfc->comp_ready);
 		nfc_writel(host->nfc->hsmc_regs, IDR, NFC_SR_RB_EDGE);
-	} else if (pending & NFC_SR_CMD_DONE) {
+		ret = IRQ_HANDLED;
+	}
+	if (pending & NFC_SR_CMD_DONE) {
 		complete(&host->nfc->comp_cmd_done);
 		nfc_writel(host->nfc->hsmc_regs, IDR, NFC_SR_CMD_DONE);
-	} else {
-		ret = IRQ_NONE;
+		ret = IRQ_HANDLED;
 	}
 
 	return ret;
@@ -1604,31 +1607,40 @@ static irqreturn_t hsmc_interrupt(int irq, void *dev_id)
 /* NFC(Nand Flash Controller) related functions */
 static int nfc_wait_interrupt(struct atmel_nand_host *host, u32 flag)
 {
-	unsigned long timeout;
-	struct completion *comp;
-
-	if (flag & NFC_SR_XFR_DONE) {
-		comp = &host->nfc->comp_xfer_done;
-	} else if (flag & NFC_SR_RB_EDGE) {
-		comp = &host->nfc->comp_ready;
-	} else if (flag & NFC_SR_CMD_DONE) {
-		comp = &host->nfc->comp_cmd_done;
-	} else {
+	int i, index = 0;
+	struct completion *comp[3];	/* Support 3 interrupt completion */
+
+	if (flag & NFC_SR_XFR_DONE)
+		comp[index++] = &host->nfc->comp_xfer_done;
+
+	if (flag & NFC_SR_RB_EDGE)
+		comp[index++] = &host->nfc->comp_ready;
+
+	if (flag & NFC_SR_CMD_DONE)
+		comp[index++] = &host->nfc->comp_cmd_done;
+
+	if (index == 0) {
 		dev_err(host->dev, "Unkown interrupt flag: 0x%08x\n", flag);
 		return -EINVAL;
 	}
 
-	init_completion(comp);
+	for (i = 0; i < index; i++)
+		init_completion(comp[i]);
 
 	/* Enable interrupt that need to wait for */
 	nfc_writel(host->nfc->hsmc_regs, IER, flag);
 
-	timeout = wait_for_completion_timeout(comp,
-			msecs_to_jiffies(NFC_TIME_OUT_MS));
-	if (timeout)
-		return 0;
+	for (i = 0; i < index; i++) {
+		if (wait_for_completion_timeout(comp[i],
+				msecs_to_jiffies(NFC_TIME_OUT_MS)))
+			continue;	/* wait for next completion */
+		else
+			goto err_timeout;
+	}
 
-	/* Time out to wait for the interrupt */
+	return 0;
+
+err_timeout:
 	dev_err(host->dev, "Time out to wait for interrupt: 0x%08x\n", flag);
 	return -ETIMEDOUT;
 }
@@ -1652,7 +1664,8 @@ static int nfc_send_command(struct atmel_nand_host *host,
 	}
 	nfc_writel(host->nfc->hsmc_regs, CYCLE0, cycle0);
 	nfc_cmd_addr1234_writel(cmd, addr, host->nfc->base_cmd_regs);
-	return nfc_wait_interrupt(host, NFC_SR_CMD_DONE);
+	return nfc_wait_interrupt(host, NFC_SR_CMD_DONE |
+			(cmd & NFCADDR_CMD_DATAEN ? NFC_SR_XFR_DONE : 0));
 }
 
 static int nfc_device_ready(struct mtd_info *mtd)
@@ -1810,10 +1823,6 @@ static void nfc_nand_command(struct mtd_info *mtd, unsigned int command,
 	nfc_addr_cmd = cmd1 | cmd2 | vcmd2 | acycle | csid | dataen | nfcwr;
 	nfc_send_command(host, nfc_addr_cmd, addr1234, cycle0);
 
-	if (dataen == NFCADDR_CMD_DATAEN)
-		if (nfc_wait_interrupt(host, NFC_SR_XFR_DONE))
-			dev_err(host->dev, "something wrong, No XFR_DONE interrupt comes.\n");
-
 	/*
 	 * Program and erase have their own busy handlers status, sequential
 	 * in, and deplete1 need no delay.
-- 
1.7.9.5