Re: [PATCH v3 1/2] mtd: nand: pxa3xx: Fix PIO FIFO draining

Robert Jarzmik
2015-02-16T21:36:34Z

Maxime Ripard <maxime.ripard@free-electrons.com> writes:

>> I don't think an mdelay(256) is acceptable.
>
> That's very true that this driver would need some love, but
> valentine's day was last week.
That doesn't cope with the 256ms mdelay. And a potential big mdelay is not what
I'd call a bug fix, see below.

> I'm sorry, but this is a patch targeted for stable. This is a pure
> bugfix. I won't rewrite the whole driver solely to make the driver
> better, especially since that would make such a patch (or more likely
> a whole serie) unsuitable for stable.

This is the rewrite I was asking for (not tested), consider it against your
"rewrite the whole driver" :

Modified drivers/mtd/nand/pxa3xx_nand.c
diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index e512902..6e569e9 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -576,11 +576,20 @@ static void start_data_dma(struct pxa3xx_nand_info *info)
{}
#endif

+static irqreturn_t pxa3xx_nand_irq_thread(int irq, void *data)
+{
+ struct pxa3xx_nand_info *info = data;
+
+ handle_data_pio(info);
+ return IRQ_HANDLED;
+}
+
static irqreturn_t pxa3xx_nand_irq(int irq, void *devid)
{
struct pxa3xx_nand_info *info = devid;
unsigned int status, is_completed = 0, is_ready = 0;
unsigned int ready, cmd_done;
+ irqreturn_t ret = IRQ_HANDLED;

if (info->cs == 0) {
ready = NDSR_FLASH_RDY;
@@ -622,7 +631,7 @@ static irqreturn_t pxa3xx_nand_irq(int irq, void *devid)
} else {
info->state = (status & NDSR_RDDREQ) ?
STATE_PIO_READING : STATE_PIO_WRITING;
- handle_data_pio(info);
+ ret = IRQ_WAKE_THREAD;
}
}
if (status & cmd_done) {
@@ -663,7 +672,7 @@ static irqreturn_t pxa3xx_nand_irq(int irq, void *devid)
if (is_ready)
complete(&info->dev_ready);
NORMAL_IRQ_EXIT:
- return IRQ_HANDLED;
+ return ret;
}

static inline int is_buf_blank(uint8_t *buf, size_t len)
@@ -1688,7 +1697,8 @@ static int alloc_nand_resource(struct platform_device *pdev)
/* initialize all interrupts to be disabled */
disable_int(info, NDSR_MASK);

- ret = request_irq(irq, pxa3xx_nand_irq, 0, pdev->name, info);
+ ret = request_threaded_irq(irq, pxa3xx_nand_irq,
+ pxa3xx_nand_irq_thread, 0, pdev->name, info);
if (ret < 0) {
dev_err(&pdev->dev, "failed to request IRQ\n");
goto fail_free_buf;

--
Robert