[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <200903111345.33154.david-b@pacbell.net>
Date: Wed, 11 Mar 2009 12:45:32 -0800
From: David Brownell <david-b@...bell.net>
To: Wolfgang Mües <wolfgang.mues@...rswald.de>
Cc: Pierre Ossman <drzeus@...eus.cx>,
"Andrew Morton" <akpm@...ux-foundation.org>,
"Matt Fleming" <matt@...sole-pimps.org>,
"Mike Frysinger" <vapier.adi@...il.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/7] mmc_spi: adjust for delayed data token response
On Wednesday 11 March 2009, Wolfgang Mües wrote:
> @@ -639,8 +640,23 @@ mmc_spi_writeblock(struct mmc_spi_host *
> * doesn't necessarily tell whether the write operation succeeded;
> * it just says if the transmission was ok and whether *earlier*
> * writes succeeded; see the standard.
> - */
> - switch (SPI_MMC_RESPONSE_CODE(scratch->status[0])) {
> + *
> + * In practice, there are (even modern SDHC-)Cards which need
> + * some bits to send the response, so we have to cope with this
All hardware needs some bits to send binary data!!
Do you mean "which don't send byte-aligned responses,
contrary to MMC/SD/SDIO specifications"?
> + * situation and check the response bit-by-bit. Arggh!!!
> + */
> + pattern = scratch->status[0] << 24;
> + pattern |= scratch->status[1] << 16;
> + pattern |= scratch->status[2] << 8;
> + pattern |= scratch->status[3];
> +
> + /* left-adjust to leading 0 bit */
> + while (pattern & 0x80000000)
> + pattern <<= 1;
> + /* right-adjust for pattern matching. Code is in bit 4..0 now. */
> + pattern >>= 27;
> +
> + switch (pattern) {
> case SPI_RESPONSE_ACCEPTED:
> status = 0;
> break;
> @@ -671,8 +687,8 @@ mmc_spi_writeblock(struct mmc_spi_host *
> /* Return when not busy. If we didn't collect that status yet,
> * we'll need some more I/O.
> */
> - for (i = 1; i < sizeof(scratch->status); i++) {
> - if (scratch->status[i] != 0)
> + for (i = 4; i < sizeof(scratch->status); i++) {
> + if (scratch->status[i] & 0x01)
I think I see why you skip four bytes, since you used
them above. But why change the "!= 0" test?
> return 0;
> }
> return mmc_spi_wait_unbusy(host, timeout);
>
> ---
> regards
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists