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From: Ulf Hansson <ulf.hansson@linaro.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Rich Felker <dalias@libc.org>,
	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 11:26:57 +0200	[thread overview]
Message-ID: <CAPDyKFrKJrUN8mJ94g0+0Vs3aT1uq9MmHWfvzcVaoA5efaYPmQ@mail.gmail.com> (raw)
In-Reply-To: <20200828042422.GA29734@lst.de>

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.

Kind regards
Uffe

  reply	other threads:[~2020-08-28  9:27 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 [this message]
2020-08-28 15:09           ` Rich Felker
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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