From aa26895af31b1ff9b52fbd2bcf85cf3ce39563a1 Mon Sep 17 00:00:00 2001 From: Evgeniy Didin Date: Wed, 14 Mar 2018 22:30:51 +0300 Subject: [PATCH] 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 Cc: Jaehoon Chung Cc: Ulf Hansson Cc: Andy Shevchenko Cc: Jisheng Zhang Cc: Shawn Lin Cc: Alexey Brodkin Cc: Eugeniy Paltsev Cc: linux-snps-arc@lists.infradead.org Cc: # 4.4+ Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/host/dw_mmc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index b821fb4bc7d1..de31e20dc56c 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -564,6 +564,7 @@ static int dw_mci_idmac_init(struct dw_mci *host) (sizeof(struct idmac_desc_64addr) * (i + 1))) >> 32; /* Initialize reserved and buffer size fields to "0" */ + p->des0 = 0; p->des1 = 0; p->des2 = 0; p->des3 = 0; @@ -586,6 +587,7 @@ static int dw_mci_idmac_init(struct dw_mci *host) i++, p++) { p->des3 = cpu_to_le32(host->sg_dma + (sizeof(struct idmac_desc) * (i + 1))); + p->des0 = 0; p->des1 = 0; } @@ -1801,8 +1803,8 @@ static bool dw_mci_reset(struct dw_mci *host) } if (host->use_dma == TRANS_MODE_IDMAC) - /* It is also recommended that we reset and reprogram idmac */ - dw_mci_idmac_reset(host); + /* It is also required that we reinit idmac */ + dw_mci_idmac_init(host); ret = true; -- 2.20.1