netdev - [PATCH net-next 12/13] net: ipa: only enable GSI general IRQs when needed

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Date:   Thu,  5 Nov 2020 12:14:06 -0600
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     evgreen@...omium.org, subashab@...eaurora.org,
        cpratapa@...eaurora.org, bjorn.andersson@...aro.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next 12/13] net: ipa: only enable GSI general IRQs when needed

Most GSI general errors are unrecoverable without a full reset.
Despite that, we want to receive these errors so we can at least
report what happened before whatever undefined behavior ensues.

Explicitly disable all such interrupts in gsi_irq_setup(), then
enable those we want in gsi_irq_enable().  List the interrupt types
we are interested in (everything but breakpoint) explicitly rather
than using GSI_CNTXT_GSI_IRQ_ALL, and remove that symbol's
definition.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/net/ipa/gsi.c     | 14 ++++++++++----
 drivers/net/ipa/gsi_reg.h |  1 -
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 5e10e5c1713b1..aa3983649bc30 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -261,6 +261,7 @@ static void gsi_irq_setup(struct gsi *gsi)
 	iowrite32(0, gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_MSK_OFFSET);
 	iowrite32(0, gsi->virt + GSI_INTER_EE_SRC_CH_IRQ_OFFSET);
 	iowrite32(0, gsi->virt + GSI_INTER_EE_SRC_EV_CH_IRQ_OFFSET);
+	iowrite32(0, gsi->virt + GSI_CNTXT_GSI_IRQ_EN_OFFSET);
 }
 
 /* Turn off all GSI interrupts when we're all done */
@@ -309,8 +310,14 @@ static void gsi_irq_enable(struct gsi *gsi)
 	iowrite32(ERROR_INT_FMASK, gsi->virt + GSI_CNTXT_GLOB_IRQ_EN_OFFSET);
 	gsi->type_enabled_bitmap |= BIT(GSI_GLOB_EE);
 
-	/* Never enable GSI_BREAK_POINT */
-	val = GSI_CNTXT_GSI_IRQ_ALL & ~BREAK_POINT_FMASK;
+	/* General GSI interrupts are reported to all EEs; if they occur
+	 * they are unrecoverable (without reset).  A breakpoint interrupt
+	 * also exists, but we don't support that.  We want to be notified
+	 * of errors so we can report them, even if they can't be handled.
+	 */
+	val = BUS_ERROR_FMASK;
+	val |= CMD_FIFO_OVRFLOW_FMASK;
+	val |= MCS_STACK_OVRFLOW_FMASK;
 	iowrite32(val, gsi->virt + GSI_CNTXT_GSI_IRQ_EN_OFFSET);
 	gsi->type_enabled_bitmap |= BIT(GSI_GENERAL);
 
@@ -1186,8 +1193,7 @@ static void gsi_isr_general(struct gsi *gsi)
 	val = ioread32(gsi->virt + GSI_CNTXT_GSI_IRQ_STTS_OFFSET);
 	iowrite32(val, gsi->virt + GSI_CNTXT_GSI_IRQ_CLR_OFFSET);
 
-	if (val)
-		dev_err(dev, "unexpected general interrupt 0x%08x\n", val);
+	dev_err(dev, "unexpected general interrupt 0x%08x\n", val);
 }
 
 /**
diff --git a/drivers/net/ipa/gsi_reg.h b/drivers/net/ipa/gsi_reg.h
index ae00aff1cfa50..c50464984c6e3 100644
--- a/drivers/net/ipa/gsi_reg.h
+++ b/drivers/net/ipa/gsi_reg.h
@@ -353,7 +353,6 @@ enum gsi_irq_type_id {
 #define BUS_ERROR_FMASK			GENMASK(1, 1)
 #define CMD_FIFO_OVRFLOW_FMASK		GENMASK(2, 2)
 #define MCS_STACK_OVRFLOW_FMASK		GENMASK(3, 3)
-#define GSI_CNTXT_GSI_IRQ_ALL		GENMASK(3, 0)
 
 #define GSI_CNTXT_INTSET_OFFSET \
 			GSI_EE_N_CNTXT_INTSET_OFFSET(GSI_EE_AP)
-- 
2.20.1