As part of xHCI bus suspend, the XHCI is halted. However, if there are
pending events in the secondary event ring, it is observed that the xHCI
controller stops responding to further commands upon host or device
initiated bus resume. Iterate through all pending events and updating the
dequeue pointer to the last pending event trb.
Signed-off-by: Wesley Cheng <[email protected]>
---
drivers/usb/host/xhci-mem.c | 74 ++++++++++++++++++++++++++++++++++---
1 file changed, 69 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index c51150af22f2..6b01d56c176f 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1799,17 +1799,85 @@ int xhci_alloc_erst(struct xhci_hcd *xhci,
return 0;
}
+static void xhci_handle_sec_intr_events(struct xhci_hcd *xhci,
+ struct xhci_ring *ring, struct xhci_intr_reg __iomem *ir_set,
+ struct xhci_erst *erst)
+{
+ union xhci_trb *erdp_trb, *current_trb;
+ struct xhci_segment *seg;
+ u64 erdp_reg;
+ u32 iman_reg;
+ dma_addr_t deq;
+ unsigned long segment_offset;
+
+ /* disable irq, ack pending interrupt and ack all pending events */
+ iman_reg = readl_relaxed(&ir_set->irq_pending);
+ iman_reg &= ~IMAN_IE;
+ writel_relaxed(iman_reg, &ir_set->irq_pending);
+ iman_reg = readl_relaxed(&ir_set->irq_pending);
+ if (iman_reg & IMAN_IP)
+ writel_relaxed(iman_reg, &ir_set->irq_pending);
+
+ /* last acked event trb is in erdp reg */
+ erdp_reg = xhci_read_64(xhci, &ir_set->erst_dequeue);
+ deq = (dma_addr_t)(erdp_reg & ~ERST_PTR_MASK);
+ if (!deq) {
+ xhci_dbg(xhci, "event ring handling not required\n");
+ return;
+ }
+
+ seg = ring->first_seg;
+ segment_offset = deq - seg->dma;
+
+ /* find out virtual address of the last acked event trb */
+ erdp_trb = current_trb = &seg->trbs[0] +
+ (segment_offset/sizeof(*current_trb));
+
+ /* read cycle state of the last acked trb to find out CCS */
+ ring->cycle_state = le32_to_cpu(current_trb->event_cmd.flags) & TRB_CYCLE;
+
+ while (1) {
+ /* last trb of the event ring: toggle cycle state */
+ if (current_trb == &seg->trbs[TRBS_PER_SEGMENT - 1]) {
+ ring->cycle_state ^= 1;
+ current_trb = &seg->trbs[0];
+ } else {
+ current_trb++;
+ }
+
+ /* cycle state transition */
+ if ((le32_to_cpu(current_trb->event_cmd.flags) & TRB_CYCLE) !=
+ ring->cycle_state)
+ break;
+ }
+
+ if (erdp_trb != current_trb) {
+ deq = xhci_trb_virt_to_dma(ring->deq_seg, current_trb);
+ if (deq == 0)
+ xhci_warn(xhci,
+ "WARN invalid SW event ring dequeue ptr.\n");
+ /* Update HC event ring dequeue pointer */
+ erdp_reg &= ERST_PTR_MASK;
+ erdp_reg |= ((u64) deq & (u64) ~ERST_PTR_MASK);
+ }
+
+ /* Clear the event handler busy flag (RW1C); event ring is empty. */
+ erdp_reg |= ERST_EHB;
+ xhci_write_64(xhci, erdp_reg, &ir_set->erst_dequeue);
+}
+
static void
xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
{
struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
size_t erst_size;
- u64 tmp64;
u32 tmp;
if (!ir)
return;
+ xhci_handle_sec_intr_events(xhci, ir->event_ring, ir->ir_set, &ir->erst);
+
erst_size = sizeof(struct xhci_erst_entry) * ir->erst.num_entries;
if (ir->erst.entries)
dma_free_coherent(dev, erst_size,
@@ -1826,10 +1894,6 @@ xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
tmp = readl(&ir->ir_set->erst_size);
tmp &= ERST_SIZE_MASK;
writel(tmp, &ir->ir_set->erst_size);
-
- tmp64 = xhci_read_64(xhci, &ir->ir_set->erst_dequeue);
- tmp64 &= (u64) ERST_PTR_MASK;
- xhci_write_64(xhci, tmp64, &ir->ir_set->erst_dequeue);
}
/* free interrrupter event ring */
On 25.7.2023 5.33, Wesley Cheng wrote:
> As part of xHCI bus suspend, the XHCI is halted. However, if there are
> pending events in the secondary event ring, it is observed that the xHCI
> controller stops responding to further commands upon host or device
> initiated bus resume. Iterate through all pending events and updating the
> dequeue pointer to the last pending event trb.
>
> Signed-off-by: Wesley Cheng <[email protected]>
> ---
> drivers/usb/host/xhci-mem.c | 74 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 69 insertions(+), 5 deletions(-)
This sounds more like ring handling code.
Maybe xhci-ring.c would be a better place
>
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index c51150af22f2..6b01d56c176f 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -1799,17 +1799,85 @@ int xhci_alloc_erst(struct xhci_hcd *xhci,
> return 0;
> }
>
> +static void xhci_handle_sec_intr_events(struct xhci_hcd *xhci,
> + struct xhci_ring *ring, struct xhci_intr_reg __iomem *ir_set,
> + struct xhci_erst *erst)
> +{
The function name is a bit misleading as it doesn't handle
any of the pending events, it just marks them all handled.
> + union xhci_trb *erdp_trb, *current_trb;
> + struct xhci_segment *seg;
> + u64 erdp_reg;
> + u32 iman_reg;
> + dma_addr_t deq;
> + unsigned long segment_offset;
> +
> + /* disable irq, ack pending interrupt and ack all pending events */
> + iman_reg = readl_relaxed(&ir_set->irq_pending);
> + iman_reg &= ~IMAN_IE;
> + writel_relaxed(iman_reg, &ir_set->irq_pending);
> + iman_reg = readl_relaxed(&ir_set->irq_pending);
> + if (iman_reg & IMAN_IP)
> + writel_relaxed(iman_reg, &ir_set->irq_pending);
maybe use xhci_disable_interrupter() helper, it does most of this already.
> +
> + /* last acked event trb is in erdp reg */
> + erdp_reg = xhci_read_64(xhci, &ir_set->erst_dequeue);
> + deq = (dma_addr_t)(erdp_reg & ~ERST_PTR_MASK);
> + if (!deq) {
> + xhci_dbg(xhci, "event ring handling not required\n");
> + return;
> + }
> +
> + seg = ring->first_seg;
> + segment_offset = deq - seg->dma;
> +
> + /* find out virtual address of the last acked event trb */
> + erdp_trb = current_trb = &seg->trbs[0] +
> + (segment_offset/sizeof(*current_trb));
> +
> + /* read cycle state of the last acked trb to find out CCS */
> + ring->cycle_state = le32_to_cpu(current_trb->event_cmd.flags) & TRB_CYCLE;
> +
> + while (1) {
> + /* last trb of the event ring: toggle cycle state */
> + if (current_trb == &seg->trbs[TRBS_PER_SEGMENT - 1]) {
> + ring->cycle_state ^= 1;
> + current_trb = &seg->trbs[0];
> + } else {
> + current_trb++;
> + }
> +
> + /* cycle state transition */
> + if ((le32_to_cpu(current_trb->event_cmd.flags) & TRB_CYCLE) !=
> + ring->cycle_state)
> + break;
> + }
> +
> + if (erdp_trb != current_trb) {
> + deq = xhci_trb_virt_to_dma(ring->deq_seg, current_trb);
> + if (deq == 0)
> + xhci_warn(xhci,
> + "WARN invalid SW event ring dequeue ptr.\n");
> + /* Update HC event ring dequeue pointer */
> + erdp_reg &= ERST_PTR_MASK;
> + erdp_reg |= ((u64) deq & (u64) ~ERST_PTR_MASK);
> + }
> +
> + /* Clear the event handler busy flag (RW1C); event ring is empty. */
> + erdp_reg |= ERST_EHB;
> + xhci_write_64(xhci, erdp_reg, &ir_set->erst_dequeue);
There are some helpers like inc_deq() and xhci_update_erst_dequeue()
that could be used here.
> +}
> +
> static void
> xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
> {
> struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
> size_t erst_size;
> - u64 tmp64;
> u32 tmp;
>
> if (!ir)
> return;
>
> + xhci_handle_sec_intr_events(xhci, ir->event_ring, ir->ir_set, &ir->erst);
Cleaning up the interrupter event ring should be called earlier.
Probably from xhci_remove_secondary_interrupter(), before it calls xhci_free_interrupter()
Thanks
-Mathias