bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0166-xhci-Use-more-event-ring-segment-table-entries.patch b/target/linux/bcm27xx/patches-5.15/950-0166-xhci-Use-more-event-ring-segment-table-entries.patch
new file mode 100644
index 0000000000..e3f72fe95e
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0166-xhci-Use-more-event-ring-segment-table-entries.patch
@@ -0,0 +1,60 @@
+From 271d837c58918de2cac5715798ebf71df43b39f7 Mon Sep 17 00:00:00 2001
+From: Jonathan Bell <jonathan@raspberrypi.org>
+Date: Tue, 13 Aug 2019 15:53:29 +0100
+Subject: [PATCH] xhci: Use more event ring segment table entries
+
+Users have reported log spam created by "Event Ring Full" xHC event
+TRBs. These are caused by interrupt latency in conjunction with a very
+busy set of devices on the bus. The errors are benign, but throughput
+will suffer as the xHC will pause processing of transfers until the
+event ring is drained by the kernel. Expand the number of event TRB slots
+available by increasing the number of event ring segments in the ERST.
+
+Controllers have a hardware-defined limit as to the number of ERST
+entries they can process, so make the actual number in use
+min(ERST_MAX_SEGS, hw_max).
+
+Signed-off-by: Jonathan Bell <jonathan@raspberrypi.org>
+---
+ drivers/usb/host/xhci-mem.c | 8 +++++---
+ drivers/usb/host/xhci.h     | 4 ++--
+ 2 files changed, 7 insertions(+), 5 deletions(-)
+
+--- a/drivers/usb/host/xhci-mem.c
++++ b/drivers/usb/host/xhci-mem.c
+@@ -2511,9 +2511,11 @@ int xhci_mem_init(struct xhci_hcd *xhci,
+ 	 * Event ring setup: Allocate a normal ring, but also setup
+ 	 * the event ring segment table (ERST).  Section 4.9.3.
+ 	 */
++	val2 = 1 << HCS_ERST_MAX(xhci->hcs_params2);
++	val2 = min_t(unsigned int, ERST_MAX_SEGS, val2);
+ 	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Allocating event ring");
+-	xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, 1, TYPE_EVENT,
+-					0, flags);
++	xhci->event_ring = xhci_ring_alloc(xhci, val2, 1, TYPE_EVENT,
++					   0, flags);
+ 	if (!xhci->event_ring)
+ 		goto fail;
+ 	if (xhci_check_trb_in_td_math(xhci) < 0)
+@@ -2526,7 +2528,7 @@ int xhci_mem_init(struct xhci_hcd *xhci,
+ 	/* set ERST count with the number of entries in the segment table */
+ 	val = readl(&xhci->ir_set->erst_size);
+ 	val &= ERST_SIZE_MASK;
+-	val |= ERST_NUM_SEGS;
++	val |= val2;
+ 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+ 			"// Write ERST size = %i to ir_set 0 (some bits preserved)",
+ 			val);
+--- a/drivers/usb/host/xhci.h
++++ b/drivers/usb/host/xhci.h
+@@ -1673,8 +1673,8 @@ struct urb_priv {
+  * Each segment table entry is 4*32bits long.  1K seems like an ok size:
+  * (1K bytes * 8bytes/bit) / (4*32 bits) = 64 segment entries in the table,
+  * meaning 64 ring segments.
+- * Initial allocated size of the ERST, in number of entries */
+-#define	ERST_NUM_SEGS	1
++ * Maximum number of segments in the ERST */
++#define	ERST_MAX_SEGS	8
+ /* Poll every 60 seconds */
+ #define	POLL_TIMEOUT	60
+ /* Stop endpoint command timeout (secs) for URB cancellation watchdog timer */