From: Rich Felker <dalias@libc.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Christoph Hellwig <hch@lst.de>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Linux-sh list <linux-sh@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
linux-spi@vger.kernel.org
Subject: Re: [PATCH 09/10] sh: don't allow non-coherent DMA for NOMMU
Date: Fri, 28 Aug 2020 11:09:43 -0400 [thread overview]
Message-ID: <20200828150942.GV3265@brightrain.aerifal.cx> (raw)
In-Reply-To: <CAPDyKFrKJrUN8mJ94g0+0Vs3aT1uq9MmHWfvzcVaoA5efaYPmQ@mail.gmail.com>
On Fri, Aug 28, 2020 at 11:26:57AM +0200, Ulf Hansson wrote:
> On Fri, 28 Aug 2020 at 06:24, Christoph Hellwig <hch@lst.de> wrote:
> >
> > On Thu, Aug 27, 2020 at 10:11:53PM -0400, Rich Felker wrote:
> > > > This change broke SD card support on J2 because MMC_SPI spuriously
> > > > depends on HAS_DMA. It looks like it can be fixed just by removing
> > > > that dependency from drivers/mmc/host/Kconfig.
> > >
> > > It can't. mmp_spi_probe fails with ENOMEM, probably due to trying to
> > > do some DMA setup thing that's not going to be needed if the
> > > underlying SPI device doesn't support/use DMA.
> >
> > Adding the linux-mmc and linux-spi lists, as that seems pretty odd.
>
> The mmc_spi driver needs modernizations, so I am not surprised to see
> odd things.
>
> My guess is that in ->probe() we check "if
> (spi->master->dev.parent->dma_mask)" - > and runs dma_map*()
> operations, which fails and leads to bailing out of ->probe() to
> return an error code.
>
> However, by looking at the code, one get the feeling that the DMA
> support is somewhat prepared to be made optional. I guess it has never
> been really tested, as the Kconfig option has "depends on HAS_DMA" -
> and it's been like that as long as I can remember.
It always worked on our "byte-banged" SPI controller, with no DMA
controller present, before Christoph's changes in this patch series,
and seems to be working now (although I have some other, hopefully
unrelated regressions to debug) with #ifdef CONFIG_HAS_DMA around the
if (spi->master->dev.parent->dma_mask) block in mmc_spi_probe. That's
probably not the right fix though -- why isn't it checking
host->dma_dev instead and only attempting DMA setup if dma_dev is
non-null?
Rich
next prev parent reply other threads:[~2020-08-28 15:10 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 12:18 ioremap and dma cleanups and fixes for superh (2nd resend) Christoph Hellwig
2020-07-14 12:18 ` [PATCH 01/10] sh: remove -Werror from Makefiles Christoph Hellwig
2020-07-14 12:18 ` [PATCH 02/10] sh: sort the selects for SUPERH alphabetically Christoph Hellwig
2020-07-14 12:18 ` [PATCH 03/10] sh: remove __KERNEL__ ifdefs from non-UAPI headers Christoph Hellwig
2020-07-14 12:18 ` [PATCH 04/10] sh: move ioremap_fixed details out of <asm/io.h> Christoph Hellwig
2020-07-14 12:18 ` [PATCH 05/10] sh: move the ioremap implementation out of line Christoph Hellwig
2020-07-14 12:18 ` [PATCH 06/10] sh: don't include <asm/io_trapped.h> in <asm/io.h> Christoph Hellwig
2020-07-14 12:18 ` [PATCH 07/10] sh: unexport register_trapped_io and match_trapped_io_handler Christoph Hellwig
2020-07-14 12:18 ` [PATCH 08/10] dma-mapping: consolidate the NO_DMA definition in kernel/dma/Kconfig Christoph Hellwig
2020-07-21 3:17 ` Rich Felker
2020-07-21 5:11 ` Christoph Hellwig
2020-07-22 0:43 ` Rich Felker
2020-07-14 12:18 ` [PATCH 09/10] sh: don't allow non-coherent DMA for NOMMU Christoph Hellwig
2020-08-28 2:00 ` Rich Felker
2020-08-28 2:11 ` Rich Felker
2020-08-28 4:24 ` Christoph Hellwig
2020-08-28 9:26 ` Ulf Hansson
2020-08-28 15:09 ` Rich Felker [this message]
2020-08-29 8:31 ` Christoph Hellwig
2020-08-31 11:28 ` Ulf Hansson
2020-07-14 12:18 ` [PATCH 10/10] sh: use the generic dma coherent remap allocator Christoph Hellwig
2020-07-14 12:31 ` ioremap and dma cleanups and fixes for superh (2nd resend) John Paul Adrian Glaubitz
2020-07-14 15:59 ` Rich Felker
2020-07-14 16:10 ` John Paul Adrian Glaubitz
2020-07-14 23:12 ` John Paul Adrian Glaubitz
2020-07-14 23:14 ` John Paul Adrian Glaubitz
2020-07-15 3:12 ` Rich Felker
2020-07-15 6:39 ` John Paul Adrian Glaubitz
2020-07-15 7:27 ` Geert Uytterhoeven
2020-07-15 7:37 ` John Paul Adrian Glaubitz
2020-07-15 8:06 ` Geert Uytterhoeven
2020-07-15 7:46 ` John Paul Adrian Glaubitz
2020-07-15 7:51 ` John Paul Adrian Glaubitz
2020-07-15 8:11 ` Geert Uytterhoeven
2020-07-15 8:27 ` John Paul Adrian Glaubitz
2020-07-15 14:37 ` John Paul Adrian Glaubitz
2020-07-15 15:39 ` John Paul Adrian Glaubitz
2020-07-15 16:18 ` John Paul Adrian Glaubitz
2020-07-15 18:21 ` Geert Uytterhoeven
2020-07-15 18:27 ` John Paul Adrian Glaubitz
2020-07-16 9:40 ` Peter Zijlstra
2020-07-16 10:05 ` John Paul Adrian Glaubitz
2020-07-16 10:29 ` peterz
2020-07-16 10:54 ` John Paul Adrian Glaubitz
2020-07-16 11:01 ` peterz
2020-07-16 11:03 ` John Paul Adrian Glaubitz
2020-07-16 11:37 ` peterz
2020-07-16 12:04 ` peterz
2020-07-16 18:14 ` John Paul Adrian Glaubitz
2020-07-16 19:28 ` Peter Zijlstra
2020-07-16 19:33 ` John Paul Adrian Glaubitz
2020-07-16 11:30 ` John Paul Adrian Glaubitz
2020-07-15 8:07 ` Geert Uytterhoeven
2020-07-16 11:31 ` John Paul Adrian Glaubitz
2020-07-20 13:38 ` Christoph Hellwig
2020-07-20 13:42 ` John Paul Adrian Glaubitz
2020-07-20 14:53 ` Rich Felker
2020-07-21 3:20 ` Rich Felker
-- strict thread matches above, loose matches on Subject: below --
2020-06-26 8:07 ioremap and dma cleanups and fixes for superh (resend) Christoph Hellwig
2020-06-26 8:07 ` [PATCH 09/10] sh: don't allow non-coherent DMA for NOMMU Christoph Hellwig
2020-06-28 1:01 ` Rob Landley
2020-06-28 7:24 ` Christoph Hellwig
2020-03-24 16:26 ioremap and dma cleanups and fixes for superh Christoph Hellwig
2020-03-24 16:26 ` [PATCH 09/10] sh: don't allow non-coherent DMA for NOMMU Christoph Hellwig
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