From: =?UTF-8?q?Martin=20Povi=C5=A1er?= <povik+lin@cutebit.org>
Date: Fri, 24 Feb 2023 16:22:20 +0100
Subject: [PATCH] dmaengine: apple-admac: Handle 'global' interrupt flags
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References: bsc#1012628
Patch-mainline: 6.2.12
Git-commit: a288fd158fbf85c06a9ac01cecabf97ac5d962e7

[ Upstream commit a288fd158fbf85c06a9ac01cecabf97ac5d962e7 ]

In addition to TX channel and RX channel interrupt flags there's
another class of 'global' interrupt flags with unknown semantics. Those
weren't being handled up to now, and they are the suspected cause of
stuck IRQ states that have been sporadically occurring. Check the global
flags and clear them if raised.

Fixes: b127315d9a78 ("dmaengine: apple-admac: Add Apple ADMAC driver")
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20230224152222.26732-1-povik+lin@cutebit.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/dma/apple-admac.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/apple-admac.c b/drivers/dma/apple-admac.c
index 90f28bda..00cbfafe 100644
--- a/drivers/dma/apple-admac.c
+++ b/drivers/dma/apple-admac.c
@@ -75,6 +75,7 @@
 
 #define REG_TX_INTSTATE(idx)		(0x0030 + (idx) * 4)
 #define REG_RX_INTSTATE(idx)		(0x0040 + (idx) * 4)
+#define REG_GLOBAL_INTSTATE(idx)	(0x0050 + (idx) * 4)
 #define REG_CHAN_INTSTATUS(ch, idx)	(0x8010 + (ch) * 0x200 + (idx) * 4)
 #define REG_CHAN_INTMASK(ch, idx)	(0x8020 + (ch) * 0x200 + (idx) * 4)
 
@@ -672,13 +673,14 @@ static void admac_handle_chan_int(struct admac_data *ad, int no)
 static irqreturn_t admac_interrupt(int irq, void *devid)
 {
 	struct admac_data *ad = devid;
-	u32 rx_intstate, tx_intstate;
+	u32 rx_intstate, tx_intstate, global_intstate;
 	int i;
 
 	rx_intstate = readl_relaxed(ad->base + REG_RX_INTSTATE(ad->irq_index));
 	tx_intstate = readl_relaxed(ad->base + REG_TX_INTSTATE(ad->irq_index));
+	global_intstate = readl_relaxed(ad->base + REG_GLOBAL_INTSTATE(ad->irq_index));
 
-	if (!tx_intstate && !rx_intstate)
+	if (!tx_intstate && !rx_intstate && !global_intstate)
 		return IRQ_NONE;
 
 	for (i = 0; i < ad->nchannels; i += 2) {
@@ -693,6 +695,12 @@ static irqreturn_t admac_interrupt(int irq, void *devid)
 		rx_intstate >>= 1;
 	}
 
+	if (global_intstate) {
+		dev_warn(ad->dev, "clearing unknown global interrupt flag: %x\n",
+			 global_intstate);
+		writel_relaxed(~(u32) 0, ad->base + REG_GLOBAL_INTSTATE(ad->irq_index));
+	}
+
 	return IRQ_HANDLED;
 }
 
-- 
2.35.3