ath10k: Keep track of which interrupts fired, don't poll them

If we have a per CE (Copy Engine) IRQ then we have no summary
register.  Right now the code generates a summary register by
iterating over all copy engines and seeing if they have an interrupt
pending.

This has a problem.  Specifically if _none_ if the Copy Engines have
an interrupt pending then they might go into low power mode and
reading from their address space will cause a full system crash.  This
was seen to happen when two interrupts went off at nearly the same
time.  Both were handled by a single call of ath10k_snoc_napi_poll()
but, because there were two interrupts handled and thus two calls to
napi_schedule() there was still a second call to
ath10k_snoc_napi_poll() which ran with no interrupts pending.

Instead of iterating over all the copy engines, let's just keep track
of the IRQs that fire.  Then we can effectively generate our own
summary without ever needing to read the Copy Engines.

Tested-on: WCN3990 SNOC WLAN.HL.3.2.2-00490-QCAHLSWMTPL-1
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Rakesh Pillai <pillair@codeaurora.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200709082024.v2.1.I4d2f85ffa06f38532631e864a3125691ef5ffe06@changeid

drivers/net/wireless/ath/ath10k/ce.c

@@ -481,38 +481,6 @@ static inline void ath10k_ce_engine_int_status_clear(struct ath10k *ar,
 	ath10k_ce_write32(ar, ce_ctrl_addr + wm_regs->addr, mask);
 }
 
-static bool ath10k_ce_engine_int_status_check(struct ath10k *ar, u32 ce_ctrl_addr,
-					      unsigned int mask)
-{
-	struct ath10k_hw_ce_host_wm_regs *wm_regs = ar->hw_ce_regs->wm_regs;
-
-	return ath10k_ce_read32(ar, ce_ctrl_addr + wm_regs->addr) & mask;
-}
-
-u32 ath10k_ce_gen_interrupt_summary(struct ath10k *ar)
-{
-	struct ath10k_hw_ce_host_wm_regs *wm_regs = ar->hw_ce_regs->wm_regs;
-	struct ath10k_ce_pipe *ce_state;
-	struct ath10k_ce *ce;
-	u32 irq_summary = 0;
-	u32 ctrl_addr;
-	u32 ce_id;
-
-	ce = ath10k_ce_priv(ar);
-
-	for (ce_id = 0; ce_id < CE_COUNT; ce_id++) {
-		ce_state = &ce->ce_states[ce_id];
-		ctrl_addr = ce_state->ctrl_addr;
-		if (ath10k_ce_engine_int_status_check(ar, ctrl_addr,
-						      wm_regs->cc_mask)) {
-			irq_summary |= BIT(ce_id);
-		}
-	}
-
-	return irq_summary;
-}
-EXPORT_SYMBOL(ath10k_ce_gen_interrupt_summary);
-
 /*
  * Guts of ath10k_ce_send.
  * The caller takes responsibility for any needed locking.
@@ -1399,45 +1367,55 @@ static void ath10k_ce_per_engine_handler_adjust(struct ath10k_ce_pipe *ce_state)
 	ath10k_ce_watermark_intr_disable(ar, ctrl_addr);
 }
 
-int ath10k_ce_disable_interrupts(struct ath10k *ar)
+void ath10k_ce_disable_interrupt(struct ath10k *ar, int ce_id)
 {
 	struct ath10k_ce *ce = ath10k_ce_priv(ar);
 	struct ath10k_ce_pipe *ce_state;
 	u32 ctrl_addr;
-	int ce_id;
 
-	for (ce_id = 0; ce_id < CE_COUNT; ce_id++) {
 	ce_state  = &ce->ce_states[ce_id];
 	if (ce_state->attr_flags & CE_ATTR_POLL)
-			continue;
+		return;
 
 	ctrl_addr = ath10k_ce_base_address(ar, ce_id);
 
 	ath10k_ce_copy_complete_intr_disable(ar, ctrl_addr);
 	ath10k_ce_error_intr_disable(ar, ctrl_addr);
 	ath10k_ce_watermark_intr_disable(ar, ctrl_addr);
-	}
+}
+EXPORT_SYMBOL(ath10k_ce_disable_interrupt);
 
-	return 0;
+void ath10k_ce_disable_interrupts(struct ath10k *ar)
+{
+	int ce_id;
+
+	for (ce_id = 0; ce_id < CE_COUNT; ce_id++)
+		ath10k_ce_disable_interrupt(ar, ce_id);
 }
 EXPORT_SYMBOL(ath10k_ce_disable_interrupts);
 
-void ath10k_ce_enable_interrupts(struct ath10k *ar)
+void ath10k_ce_enable_interrupt(struct ath10k *ar, int ce_id)
 {
 	struct ath10k_ce *ce = ath10k_ce_priv(ar);
-	int ce_id;
 	struct ath10k_ce_pipe *ce_state;
 
-	/* Enable interrupts for copy engine that
-	 * are not using polling mode.
-	 */
-	for (ce_id = 0; ce_id < CE_COUNT; ce_id++) {
 	ce_state  = &ce->ce_states[ce_id];
 	if (ce_state->attr_flags & CE_ATTR_POLL)
-			continue;
+		return;
 
 	ath10k_ce_per_engine_handler_adjust(ce_state);
-	}
+}
+EXPORT_SYMBOL(ath10k_ce_enable_interrupt);
+
+void ath10k_ce_enable_interrupts(struct ath10k *ar)
+{
+	int ce_id;
+
+	/* Enable interrupts for copy engine that
+	 * are not using polling mode.
+	 */
+	for (ce_id = 0; ce_id < CE_COUNT; ce_id++)
+		ath10k_ce_enable_interrupt(ar, ce_id);
 }
 EXPORT_SYMBOL(ath10k_ce_enable_interrupts);
 

drivers/net/wireless/ath/ath10k/ce.h

@@ -255,12 +255,13 @@ int ath10k_ce_cancel_send_next(struct ath10k_ce_pipe *ce_state,
 /*==================CE Interrupt Handlers====================*/
 void ath10k_ce_per_engine_service_any(struct ath10k *ar);
 void ath10k_ce_per_engine_service(struct ath10k *ar, unsigned int ce_id);
-int ath10k_ce_disable_interrupts(struct ath10k *ar);
+void ath10k_ce_disable_interrupt(struct ath10k *ar, int ce_id);
+void ath10k_ce_disable_interrupts(struct ath10k *ar);
+void ath10k_ce_enable_interrupt(struct ath10k *ar, int ce_id);
 void ath10k_ce_enable_interrupts(struct ath10k *ar);
 void ath10k_ce_dump_registers(struct ath10k *ar,
 			      struct ath10k_fw_crash_data *crash_data);
 
-u32 ath10k_ce_gen_interrupt_summary(struct ath10k *ar);
 void ath10k_ce_alloc_rri(struct ath10k *ar);
 void ath10k_ce_free_rri(struct ath10k *ar);
 
@@ -376,12 +377,9 @@ static inline u32 ath10k_ce_interrupt_summary(struct ath10k *ar)
 {
 	struct ath10k_ce *ce = ath10k_ce_priv(ar);
 
-	if (!ar->hw_params.per_ce_irq)
 	return CE_WRAPPER_INTERRUPT_SUMMARY_HOST_MSI_GET(
 		ce->bus_ops->read32((ar), CE_WRAPPER_BASE_ADDRESS +
 		CE_WRAPPER_INTERRUPT_SUMMARY_ADDRESS));
-	else
-		return ath10k_ce_gen_interrupt_summary(ar);
 }
 
 /* Host software's Copy Engine configuration. */

drivers/net/wireless/ath/ath10k/snoc.c

@@ -3,6 +3,7 @@
  * Copyright (c) 2018 The Linux Foundation. All rights reserved.
  */
 
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -923,6 +924,7 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
 {
 	struct ath10k_snoc *ar_snoc = ath10k_snoc_priv(ar);
 
+	bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
 	napi_enable(&ar->napi);
 	ath10k_snoc_irq_enable(ar);
 	ath10k_snoc_rx_post(ar);
@@ -1158,7 +1160,9 @@ static irqreturn_t ath10k_snoc_per_engine_handler(int irq, void *arg)
 		return IRQ_HANDLED;
 	}
 
-	ath10k_snoc_irq_disable(ar);
+	ath10k_ce_disable_interrupt(ar, ce_id);
+	set_bit(ce_id, ar_snoc->pending_ce_irqs);
+
 	napi_schedule(&ar->napi);
 
 	return IRQ_HANDLED;
@@ -1167,20 +1171,25 @@ static irqreturn_t ath10k_snoc_per_engine_handler(int irq, void *arg)
 static int ath10k_snoc_napi_poll(struct napi_struct *ctx, int budget)
 {
 	struct ath10k *ar = container_of(ctx, struct ath10k, napi);
+	struct ath10k_snoc *ar_snoc = ath10k_snoc_priv(ar);
 	int done = 0;
+	int ce_id;
 
 	if (test_bit(ATH10K_FLAG_CRASH_FLUSH, &ar->dev_flags)) {
 		napi_complete(ctx);
 		return done;
 	}
 
-	ath10k_ce_per_engine_service_any(ar);
+	for (ce_id = 0; ce_id < CE_COUNT; ce_id++)
+		if (test_and_clear_bit(ce_id, ar_snoc->pending_ce_irqs)) {
+			ath10k_ce_per_engine_service(ar, ce_id);
+			ath10k_ce_enable_interrupt(ar, ce_id);
+		}
+
 	done = ath10k_htt_txrx_compl_task(ar, budget);
 
-	if (done < budget) {
+	if (done < budget)
 		napi_complete(ctx);
-		ath10k_snoc_irq_enable(ar);
-	}
 
 	return done;
 }

drivers/net/wireless/ath/ath10k/snoc.h

@@ -78,6 +78,7 @@ struct ath10k_snoc {
 	unsigned long flags;
 	bool xo_cal_supported;
 	u32 xo_cal_data;
+	DECLARE_BITMAP(pending_ce_irqs, CE_COUNT_MAX);
 };
 
 static inline struct ath10k_snoc *ath10k_snoc_priv(struct ath10k *ar)