Merge tag 'socfpga_fix_for_v5.16_part_3' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux into arm/fixes

SoCFPGA dts updates for v5.16, part 3
- Change the SoCFPGA compatible to "intel,socfpga-qspi"
- Update dt-bindings document to include "intel,socfpga-qspi"

* tag 'socfpga_fix_for_v5.16_part_3' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux: (361 commits)
  ARM: dts: socfpga: change qspi to "intel,socfpga-qspi"
  dt-bindings: spi: cadence-quadspi: document "intel,socfpga-qspi"
  Linux 5.16-rc7
  mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page()
  mm/damon/dbgfs: protect targets destructions with kdamond_lock
  mm/page_alloc: fix __alloc_size attribute for alloc_pages_exact_nid
  mm: delete unsafe BUG from page_cache_add_speculative()
  mm, hwpoison: fix condition in free hugetlb page path
  MAINTAINERS: mark more list instances as moderated
  kernel/crash_core: suppress unknown crashkernel parameter warning
  mm: mempolicy: fix THP allocations escaping mempolicy restrictions
  kfence: fix memory leak when cat kfence objects
  platform/x86: intel_pmc_core: fix memleak on registration failure
  net: stmmac: dwmac-visconti: Fix value of ETHER_CLK_SEL_FREQ_SEL_2P5M
  r8152: sync ocp base
  r8152: fix the force speed doesn't work for RTL8156
  net: bridge: fix ioctl old_deviceless bridge argument
  net: stmmac: ptp: fix potentially overflowing expression
  net: dsa: tag_ocelot: use traffic class to map priority on injected header
  veth: ensure skb entering GRO are not cloned.
  ...

Link: https://lore.kernel.org/r/20211227103644.566694-1-dinguyen@kernel.org
Signed-off-by: Olof Johansson <olof@lixom.net>

1 files changed, 27 insertions, 3 deletions

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 71e0dd2c0ce5..ebaf7500f48f 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -37,6 +37,8 @@ struct xencons_info {
 	struct xenbus_device *xbdev;
 	struct xencons_interface *intf;
 	unsigned int evtchn;
+	XENCONS_RING_IDX out_cons;
+	unsigned int out_cons_same;
 	struct hvc_struct *hvc;
 	int irq;
 	int vtermno;
@@ -138,6 +140,8 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
 	XENCONS_RING_IDX cons, prod;
 	int recv = 0;
 	struct xencons_info *xencons = vtermno_to_xencons(vtermno);
+	unsigned int eoiflag = 0;
+
 	if (xencons == NULL)
 		return -EINVAL;
 	intf = xencons->intf;
@@ -157,7 +161,27 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
 	mb();			/* read ring before consuming */
 	intf->in_cons = cons;
 
-	notify_daemon(xencons);
+	/*
+	 * When to mark interrupt having been spurious:
+	 * - there was no new data to be read, and
+	 * - the backend did not consume some output bytes, and
+	 * - the previous round with no read data didn't see consumed bytes
+	 *   (we might have a race with an interrupt being in flight while
+	 *   updating xencons->out_cons, so account for that by allowing one
+	 *   round without any visible reason)
+	 */
+	if (intf->out_cons != xencons->out_cons) {
+		xencons->out_cons = intf->out_cons;
+		xencons->out_cons_same = 0;
+	}
+	if (recv) {
+		notify_daemon(xencons);
+	} else if (xencons->out_cons_same++ > 1) {
+		eoiflag = XEN_EOI_FLAG_SPURIOUS;
+	}
+
+	xen_irq_lateeoi(xencons->irq, eoiflag);
+
 	return recv;
 }
 
@@ -386,7 +410,7 @@ static int xencons_connect_backend(struct xenbus_device *dev,
 	if (ret)
 		return ret;
 	info->evtchn = evtchn;
-	irq = bind_evtchn_to_irq(evtchn);
+	irq = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
 	if (irq < 0)
 		return irq;
 	info->irq = irq;
@@ -551,7 +575,7 @@ static int __init xen_hvc_init(void)
 			return r;
 
 		info = vtermno_to_xencons(HVC_COOKIE);
-		info->irq = bind_evtchn_to_irq(info->evtchn);
+		info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
 	}
 	if (info->irq < 0)
 		info->irq = 0; /* NO_IRQ */