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Message-ID: <20141216003756.15488.34861.stgit@dizzy-6.o2s.ch>
Date: Tue, 16 Dec 2014 01:37:56 +0100
From: David Lanzendörfer <david.lanzendoerfer@....ch>
To: Ulf Hansson <ulf.hansson@...aro.org>,
Tomeu Vizoso <tomeu.vizoso@...labora.com>,
Arnd Bergmann <arnd@...db.de>, linux-mmc@...r.kernel.org,
Chris Ball <chris@...ntf.net>, linux-kernel@...r.kernel.org,
Peter Griffin <peter.griffin@...aro.org>,
Hans de Goede <hdegoede@...hat.com>,
Chen-Yu Tsai <wens@...e.org>,
David Lanzendörfer <david.lanzendoerfer@....ch>,
李想 <lixiang@...winnertech.com>,
Maxime Ripard <maxime.ripard@...e-electrons.com>,
linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 3/4] mmc: sunxi: Reset behavior fix
When there is only one DES available the DMA performs a FIFO reset and waits until the reinitialization has been completed.
Disabling the SDXC_IDMAC_DES0_DIC bit prevents the DMA from sending an interrupt after it has finished this reinitialization.
The flags SDXC_IDMAC_DES0_FD and SDXC_IDMAC_DES0_LD are both required in order to use the controller with more than one DES.
Signed-off-by: David Lanzendörfer <david.lanzendoerfer@....ch>
Reported-by: 李想 <lixiang@...winnertech.com>
---
drivers/mmc/host/sunxi-mmc.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 50bd3d2..5331c88 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -310,7 +310,17 @@ static void sunxi_mmc_init_idma_des(struct sunxi_mmc_host *host,
}
pdes[0].config |= SDXC_IDMAC_DES0_FD;
- pdes[i - 1].config = SDXC_IDMAC_DES0_OWN | SDXC_IDMAC_DES0_LD;
+
+ /*
+ * When there is only one DES available the DMA performs a FIFO reset and waits
+ * until the reinitialization has been completed.
+ * Disabling the SDXC_IDMAC_DES0_DIC bit prevents the DMA from sending an interrupt
+ * after it has finished this reinitialization.
+ */
+ pdes[i - 1].config = SDXC_IDMAC_DES0_OWN;
+ pdes[i - 1].config |= SDXC_IDMAC_DES0_FD;
+ pdes[i - 1].config |= SDXC_IDMAC_DES0_LD;
+ pdes[i - 1].config &= ~SDXC_IDMAC_DES0_DIC;
/*
* Avoid the io-store starting the idmac hitting io-mem before the
--
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