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SubjectRe: [PATCH] mtd: fix timeout in M25P80 driver
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On Mon, 2009-04-13 at 15:26 +0100, Peter Horton wrote:
> Extend erase timeout in M25P80 SPI Flash driver.
>
> The M25P80 drivers fails erasing sectors on a M25P128 because the ready
> wait timeout is too short. Change the timeout from a simple loop count to a
> suitable number of seconds.
>
> Signed-off-by: Peter Horton <zero@colonel-panic.org>
> ---
> Index: linux-2.6.29-git12/drivers/mtd/devices/m25p80.c
> ===================================================================
> --- linux-2.6.29-git12.orig/drivers/mtd/devices/m25p80.c 2009-04-12 21:41:16.000000000 +0000
> +++ linux-2.6.29-git12/drivers/mtd/devices/m25p80.c 2009-04-12 21:43:01.000000000 +0000
> @@ -54,7 +54,7 @@
> #define SR_SRWD 0x80 /* SR write protect */
>
> /* Define max times to check status register before we give up. */
> -#define MAX_READY_WAIT_COUNT 100000
> +#define MAX_READY_WAIT_JIFFIES (10 * HZ) /* eg. M25P128 specs 6s max sector erase */
> #define CMD_SIZE 4
>
> #ifdef CONFIG_M25PXX_USE_FAST_READ
> @@ -145,20 +145,20 @@
> */
> static int wait_till_ready(struct m25p *flash)
> {
> - int count;
> + unsigned long deadline;
> int sr;
>
> - /* one chip guarantees max 5 msec wait here after page writes,
> - * but potentially three seconds (!) after page erase.
> - */
Why did you remove the comment? Is it wrong or useless?

> - for (count = 0; count < MAX_READY_WAIT_COUNT; count++) {
> + deadline = jiffies + MAX_READY_WAIT_JIFFIES;
> +
> + do {
> if ((sr = read_sr(flash)) < 0)
> break;
> else if (!(sr & SR_WIP))
> return 0;
>
> - /* REVISIT sometimes sleeping would be best */
> - }
> + cond_resched();
> +
> + } while (!time_after_eq(jiffies, deadline));
>
> return 1;
> }

--
Best regards,
Artem Bityutskiy (Битюцкий Артём)

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