[U-Boot] [PATCH v2] mmc: fsl_esdhc: Avoid infinite loop in esdhc_send_cmd_common()
Peter Robinson
pbrobinson at gmail.com
Mon Nov 19 13:24:47 UTC 2018
On Mon, Nov 19, 2018 at 12:31 PM Fabio Estevam <festevam at gmail.com> wrote:
>
> The following hang is observed on a Hummingboard 2 MicroSOM
> i2eX iMX6D - rev 1.3 with no eMMC populated on board:
>
> U-Boot SPL 2018.11+gf6206f8587 (Nov 16 2018 - 00:56:34 +0000)
> Trying to boot from MMC1
>
> U-Boot 2018.11+gf6206f8587 (Nov 16 2018 - 00:56:34 +0000)
>
> CPU: Freescale i.MX6D rev1.5 996 MHz (running at 792 MHz)
> CPU: Extended Commercial temperature grade (-20C to 105C) at 33C
> Reset cause: POR
> Board: MX6 HummingBoard2
> DRAM: 1 GiB
> MMC: FSL_SDHC: 0, FSL_SDHC: 1
> Loading Environment from MMC... *** Warning - bad CRC, using default environment
>
> No panel detected: default to HDMI
> Display: HDMI (1024x768)
> In: serial
> Out: serial
> Err: serial
> ---> hangs
>
> which is caused by the following infinite loop inside esdhc_send_cmd_common()
>
> while (!(esdhc_read32(®s->irqstat) & flags))
> ;
>
> Instead of looping forever, provide an exit path so that a timeout
> error can be propagated in the case irqstat does not report
> any interrupts, which may happen when no eMMC is populated on
> board.
>
> Reported-by: Ricardo Salveti <rsalveti at rsalveti.net>
> Signed-off-by: Fabio Estevam <festevam at gmail.com>
Tested-by: Peter Robinson <pbrobinson at gmail.com>
Boots fine on my i.MX6 Quad hummingboard2 with SOM rev 1.5 which
previously has the problem I reported back in 2018.09 series.
Peter
> ---
> Changes since v1:
> - Jump to the label out on error path (Baruch).
>
> drivers/mmc/fsl_esdhc.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index 3cdfa7f..b8d0b00 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -396,6 +396,7 @@ static int esdhc_send_cmd_common(struct fsl_esdhc_priv *priv, struct mmc *mmc,
> uint irqstat;
> u32 flags = IRQSTAT_CC | IRQSTAT_CTOE;
> struct fsl_esdhc *regs = priv->esdhc_regs;
> + unsigned long start;
>
> #ifdef CONFIG_SYS_FSL_ERRATUM_ESDHC111
> if (cmd->cmdidx == MMC_CMD_STOP_TRANSMISSION)
> @@ -453,8 +454,13 @@ static int esdhc_send_cmd_common(struct fsl_esdhc_priv *priv, struct mmc *mmc,
> flags = IRQSTAT_BRR;
>
> /* Wait for the command to complete */
> - while (!(esdhc_read32(®s->irqstat) & flags))
> - ;
> + start = get_timer(0);
> + while (!(esdhc_read32(®s->irqstat) & flags)) {
> + if (get_timer(start) > 1000) {
> + err = -ETIMEDOUT;
> + goto out;
> + }
> + }
>
> irqstat = esdhc_read32(®s->irqstat);
>
> --
> 2.7.4
>
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