mmc: dw_mmc: fix falling from idmac to PIO mode when dw_mci_reset occurs
authorEvgeniy Didin <Evgeniy.Didin@synopsys.com>
Wed, 14 Mar 2018 19:30:51 +0000 (22:30 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 28 Mar 2018 16:24:32 +0000 (18:24 +0200)
commitaa26895af31b1ff9b52fbd2bcf85cf3ce39563a1
tree4bd12cefaf1c61af9c2115d160c7f195c85fb2aa
parenta592984e03e65e81baff2efd058932e2ac56b60d
mmc: dw_mmc: fix falling from idmac to PIO mode when dw_mci_reset occurs

commit 47b7de2f6c18f75d1f2716efe752cba43f32a626 upstream.

It was found that in IDMAC mode after soft-reset driver switches
to PIO mode.

That's what happens in case of DTO timeout overflow calculation failure:
1. soft-reset is called
2. driver restarts dma
3. descriptors states are checked, one of descriptor is owned by the IDMAC.
4. driver can't use DMA and then switches to PIO mode.

Failure was already fixed in:
https://www.spinics.net/lists/linux-mmc/msg48125.html.

Behaviour while soft-reset is not something we except or
even want to happen. So we switch from dw_mci_idmac_reset
to dw_mci_idmac_init, so descriptors are cleaned before starting dma.

And while at it explicitly zero des0 which otherwise might
contain garbage as being allocated by dmam_alloc_coherent().

Signed-off-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Cc: <stable@vger.kernel.org> # 4.4+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/mmc/host/dw_mmc.c