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From 09648b92a71b03450e9482f0cc5bd22298f78d44 Mon Sep 17 00:00:00 2001
From: Jonathan Bell <jonathan@raspberrypi.org>
Date: Wed, 8 Jan 2020 12:48:09 +0000
Subject: [PATCH] dwc_otg: fiq_fsm: pause when cancelling split
transactions
Non-periodic splits will DMA to/from the driver-provided transfer_buffer,
which may be freed immediately after the dequeue call returns. Block until
we know the transfer is complete.
A similar delay is needed when cleaning up disconnects, as the FIQ could
have started a periodic transfer in the previous microframe to the one
that triggered a disconnect.
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.org>
---
drivers/usb/host/dwc_otg/dwc_otg_hcd.c | 33 +++++++++++++++++++++--
drivers/usb/host/dwc_otg/dwc_otg_os_dep.h | 1 +
2 files changed, 32 insertions(+), 2 deletions(-)
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
@@ -175,6 +175,7 @@ static void kill_urbs_in_qh_list(dwc_otg
dwc_list_link_t *qh_item, *qh_tmp;
dwc_otg_qh_t *qh;
dwc_otg_qtd_t *qtd, *qtd_tmp;
+ int quiesced = 0;
DWC_LIST_FOREACH_SAFE(qh_item, qh_tmp, qh_list) {
qh = DWC_LIST_ENTRY(qh_item, dwc_otg_qh_t, qh_list_entry);
@@ -198,8 +199,17 @@ static void kill_urbs_in_qh_list(dwc_otg
qh->channel->halt_status = DWC_OTG_HC_XFER_URB_DEQUEUE;
qh->channel->halt_pending = 1;
if (hcd->fiq_state->channel[n].fsm == FIQ_HS_ISOC_TURBO ||
- hcd->fiq_state->channel[n].fsm == FIQ_HS_ISOC_SLEEPING)
+ hcd->fiq_state->channel[n].fsm == FIQ_HS_ISOC_SLEEPING)
hcd->fiq_state->channel[n].fsm = FIQ_HS_ISOC_ABORTED;
+ /* We're called from disconnect callback or in the middle of freeing the HCD here,
+ * so FIQ is disabled, top-level interrupts masked and we're holding the spinlock.
+ * No further URBs will be submitted, but wait 1 microframe for any previously
+ * submitted periodic DMA to finish.
+ */
+ if (!quiesced) {
+ udelay(125);
+ quiesced = 1;
+ }
} else {
dwc_otg_hc_halt(hcd->core_if, qh->channel,
DWC_OTG_HC_XFER_URB_DEQUEUE);
@@ -600,15 +610,34 @@ int dwc_otg_hcd_urb_dequeue(dwc_otg_hcd_
/* In FIQ FSM mode, we need to shut down carefully.
* The FIQ may attempt to restart a disabled channel */
if (fiq_fsm_enable && (hcd->fiq_state->channel[n].fsm != FIQ_PASSTHROUGH)) {
+ int retries = 3;
+ int running = 0;
+ enum fiq_fsm_state state;
+
local_fiq_disable();
fiq_fsm_spin_lock(&hcd->fiq_state->lock);
qh->channel->halt_status = DWC_OTG_HC_XFER_URB_DEQUEUE;
qh->channel->halt_pending = 1;
if (hcd->fiq_state->channel[n].fsm == FIQ_HS_ISOC_TURBO ||
- hcd->fiq_state->channel[n].fsm == FIQ_HS_ISOC_SLEEPING)
+ hcd->fiq_state->channel[n].fsm == FIQ_HS_ISOC_SLEEPING)
hcd->fiq_state->channel[n].fsm = FIQ_HS_ISOC_ABORTED;
fiq_fsm_spin_unlock(&hcd->fiq_state->lock);
local_fiq_enable();
+
+ if (dwc_qh_is_non_per(qh)) {
+ do {
+ state = READ_ONCE(hcd->fiq_state->channel[n].fsm);
+ running = (state != FIQ_NP_SPLIT_DONE) &&
+ (state != FIQ_NP_SPLIT_LS_ABORTED) &&
+ (state != FIQ_NP_SPLIT_HS_ABORTED);
+ if (!running)
+ break;
+ udelay(125);
+ } while(--retries);
+ if (!retries)
+ DWC_WARN("Timed out waiting for FSM NP transfer to complete on %d",
+ qh->channel->hc_num);
+ }
} else {
dwc_otg_hc_halt(hcd->core_if, qh->channel,
DWC_OTG_HC_XFER_URB_DEQUEUE);
--- a/drivers/usb/host/dwc_otg/dwc_otg_os_dep.h
+++ b/drivers/usb/host/dwc_otg/dwc_otg_os_dep.h
@@ -27,6 +27,7 @@
#include <linux/workqueue.h>
#include <linux/stat.h>
#include <linux/pci.h>
+#include <linux/compiler.h>
#include <linux/version.h>
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