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Message-ID: <002901d65505$cf84e980$6e8ebc80$@codeaurora.org>
Date: Wed, 8 Jul 2020 14:27:23 +0530
From: "Rakesh Pillai" <pillair@...eaurora.org>
To: "'Douglas Anderson'" <dianders@...omium.org>,
<kvalo@...eaurora.org>, <ath10k@...ts.infradead.org>
Cc: <saiprakash.ranjan@...eaurora.org>,
<linux-arm-msm@...r.kernel.org>, <linux-wireless@...r.kernel.org>,
<kuabhs@...gle.com>, "'David S. Miller'" <davem@...emloft.net>,
"'Jakub Kicinski'" <kuba@...nel.org>,
<linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: RE: [PATCH] ath10k: Keep track of which interrupts fired, don't poll them
> -----Original Message-----
> From: Douglas Anderson <dianders@...omium.org>
> Sent: Tuesday, July 7, 2020 10:48 PM
> To: kvalo@...eaurora.org; ath10k@...ts.infradead.org
> Cc: saiprakash.ranjan@...eaurora.org; linux-arm-msm@...r.kernel.org;
> linux-wireless@...r.kernel.org; pillair@...eaurora.org;
> kuabhs@...gle.com; Douglas Anderson <dianders@...omium.org>; David
> S. Miller <davem@...emloft.net>; Jakub Kicinski <kuba@...nel.org>; linux-
> kernel@...r.kernel.org; netdev@...r.kernel.org
> Subject: [PATCH] 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@...omium.org>
Reviewed-by: Rakesh Pillai <pillair@...eaurora.org>
> ---
> This patch continues work to try to squash all instances of the crash
> we've been seeing while reading CE registers and hopefully this patch
> addresses the true root of the issue.
>
> The first patch that attempted to address these problems landed as
> commit 8f9ed93d09a9 ("ath10k: Wait until copy complete is actually
> done before completing"). After that Rakesh Pillai posted ("ath10k:
> Add interrupt summary based CE processing") [1] and this patch is
> based atop that one. Both of those patches significantly reduced the
> instances of problems but didn't fully eliminate them. Crossing my
> fingers that they're all gone now.
>
> [1] https://lore.kernel.org/r/1593193967-29897-1-git-send-email-
> pillair@...eaurora.org
>
> drivers/net/wireless/ath/ath10k/ce.c | 84 ++++++++++----------------
> drivers/net/wireless/ath/ath10k/ce.h | 14 ++---
> drivers/net/wireless/ath/ath10k/snoc.c | 18 ++++--
> drivers/net/wireless/ath/ath10k/snoc.h | 1 +
> 4 files changed, 51 insertions(+), 66 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/ce.c
> b/drivers/net/wireless/ath/ath10k/ce.c
> index 1e16f263854a..84ec80c6d08f 100644
> --- a/drivers/net/wireless/ath/ath10k/ce.c
> +++ b/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;
> + ce_state = &ce->ce_states[ce_id];
> + if (ce_state->attr_flags & CE_ATTR_POLL)
> + return;
>
> - ctrl_addr = ath10k_ce_base_address(ar, ce_id);
> + 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);
> - }
> + 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;
>
> + ce_state = &ce->ce_states[ce_id];
> + if (ce_state->attr_flags & CE_ATTR_POLL)
> + 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++) {
> - ce_state = &ce->ce_states[ce_id];
> - if (ce_state->attr_flags & CE_ATTR_POLL)
> - continue;
> -
> - ath10k_ce_per_engine_handler_adjust(ce_state);
> - }
> + for (ce_id = 0; ce_id < CE_COUNT; ce_id++)
> + ath10k_ce_enable_interrupt(ar, ce_id);
> }
> EXPORT_SYMBOL(ath10k_ce_enable_interrupts);
>
> diff --git a/drivers/net/wireless/ath/ath10k/ce.h
> b/drivers/net/wireless/ath/ath10k/ce.h
> index a440aaf74aa4..666ce384a1d8 100644
> --- a/drivers/net/wireless/ath/ath10k/ce.h
> +++ b/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);
> + return CE_WRAPPER_INTERRUPT_SUMMARY_HOST_MSI_GET(
> + ce->bus_ops->read32((ar), CE_WRAPPER_BASE_ADDRESS +
> + CE_WRAPPER_INTERRUPT_SUMMARY_ADDRESS));
> }
>
> /* Host software's Copy Engine configuration. */
> diff --git a/drivers/net/wireless/ath/ath10k/snoc.c
> b/drivers/net/wireless/ath/ath10k/snoc.c
> index 354d49b1cd45..2fc4dcbab70a 100644
> --- a/drivers/net/wireless/ath/ath10k/snoc.c
> +++ b/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>
> @@ -1158,7 +1159,9 @@ 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 +1170,25 @@ 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;
> }
> diff --git a/drivers/net/wireless/ath/ath10k/snoc.h
> b/drivers/net/wireless/ath/ath10k/snoc.h
> index a3dd06f6ac62..5095d1893681 100644
> --- a/drivers/net/wireless/ath/ath10k/snoc.h
> +++ b/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)
> --
> 2.27.0.383.g050319c2ae-goog
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