I have encountered an interrupt storm during the eMMC chip probing (and
the chip finally didn't get detected). It turned out that U-Boot left
the SDHI DMA interrupts enabled while the Linux driver didn't use those.
Masking those interrupts in renesas_sdhi_internal_dmac_request_dma() gets
rid of both issues...
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
---
The patch is against Ulf Hansson's 'mmc.git' repo's 'fixes' branch.
drivers/mmc/host/renesas_sdhi_internal_dmac.c | 11 +++++++++++
1 file changed, 11 insertions(+)
Index: mmc/drivers/mmc/host/renesas_sdhi_internal_dmac.c
===================================================================
--- mmc.orig/drivers/mmc/host/renesas_sdhi_internal_dmac.c
+++ mmc/drivers/mmc/host/renesas_sdhi_internal_dmac.c
@@ -51,10 +51,12 @@
#define INFO1_CLEAR 0
#define INFO1_DTRANEND1 BIT(17)
#define INFO1_DTRANEND0 BIT(16)
+#define INFO1_RESERVED_BITS GENMASK_ULL(32, 0)
/* DM_CM_INFO2 and DM_CM_INFO2_MASK */
#define INFO2_DTRANERR1 BIT(17)
#define INFO2_DTRANERR0 BIT(16)
+#define INFO2_RESERVED_BITS GENMASK_ULL(32, 0)
/*
* Specification of this driver:
@@ -236,6 +238,15 @@ renesas_sdhi_internal_dmac_request_dma(s
{
struct renesas_sdhi *priv = host_to_priv(host);
+ /*
+ * We don't use the DMA interrupts, but they might have been enabled
+ * by a bootloader, so mask them to avoid an interrupt storm...
+ */
+ renesas_sdhi_internal_dmac_dm_write(host, DM_CM_INFO1_MASK,
+ INFO1_RESERVED_BITS);
+ renesas_sdhi_internal_dmac_dm_write(host, DM_CM_INFO2_MASK,
+ INFO2_RESERVED_BITS);
+
/* Each value is set to non-zero to assume "enabling" each DMA */
host->chan_rx = host->chan_tx = (void *)0xdeadbeaf;
