From: Sascha Hauer <s.hauer@pengutronix.de>
To: Michael Olbrich <m.olbrich@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] mci: mmci: Fix read FIFO handling
Date: Mon, 5 Sep 2016 08:31:07 +0200 [thread overview]
Message-ID: <20160905063107.yrndcugua7m3zxsk@pengutronix.de> (raw)
In-Reply-To: <20160902085037.11653-1-m.olbrich@pengutronix.de>
On Fri, Sep 02, 2016 at 10:50:37AM +0200, Michael Olbrich wrote:
> According to the Linux kernel and the qemu code, the MMCIFIFOCNT contains
> the remaining number of words to read, excluding those that are already in
> the FIFO. So the current number of bytes in the FIFO is
> host_remain - (readl(base + MMCIFIFOCNT) << 2).
>
> Also writing to MMCIDATACTRL will reset the read counter. As a result,
> MCI_DATABLOCKEND is never set and read_bytes() waits forever.
>
> With this change, SD-Card support on qemu vexpress works correctly.
>
> Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
> ---
> drivers/mci/mmci.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
Applied, thanks
Sascha
>
> diff --git a/drivers/mci/mmci.c b/drivers/mci/mmci.c
> index 9d1e858917de..7489ee03a13c 100644
> --- a/drivers/mci/mmci.c
> +++ b/drivers/mci/mmci.c
> @@ -212,7 +212,7 @@ static u64 mmci_pio_read(struct mmci_host *host, char *buffer, unsigned int host
> struct variant_data *variant = host->variant;
>
> do {
> - int count = readl(base + MMCIFIFOCNT) << 2;
> + int count = host_remain - (readl(base + MMCIFIFOCNT) << 2);
>
> if (count > host_remain)
> count = host_remain;
> @@ -264,7 +264,6 @@ static int read_bytes(struct mci_host *mci, char *dest, unsigned int blkcount, u
> dev_dbg(host->hw_dev, "read_bytes: blkcount=%u blksize=%u\n", blkcount, blksize);
>
> do {
> - mmci_writel(host, MMCIDATACTRL, mmci_readl(host, MMCIDATACTRL));
> len = mmci_pio_read(host, dest, xfercount);
> xfercount -= len;
> dest += len;
> --
> 2.9.3
>
>
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
>
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prev parent reply other threads:[~2016-09-05 6:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-02 8:50 Michael Olbrich
2016-09-05 6:31 ` Sascha Hauer [this message]
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