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From: Daehwan Jung <dh10.jung@samsung.com>
To: Mathias Nyman <mathias.nyman@intel.com>, Greg Kroah-Hartman
	<gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org (open list:USB XHCI DRIVER),
	linux-kernel@vger.kernel.org (open list), Thinh Nguyen
	<Thinh.Nguyen@synopsys.com>, Daehwan Jung <dh10.jung@samsung.com>
Subject: [RFC] usb: host: xhci-mem: Write high first on erst base of
 secondary interrupter
Date: Wed, 22 May 2024 10:03:59 +0900
Message-Id: <1716339839-44022-1-git-send-email-dh10.jung@samsung.com>
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References: <CGME20240522010409epcas2p457b2fcb4f423f2500305053f44ae3199@epcas2p4.samsung.com>
Precedence: bulk

ERSTBA_HI should be written first on secondary interrupter.
That's why secondary interrupter could be set while Host Controller
is already running.

[Synopsys]- The host controller was design to support ERST setting
during the RUN state. But since there is a limitation in controller
in supporting separate ERSTBA_HI and ERSTBA_LO programming,
It is supported when the ERSTBA is programmed in 64bit,
or in 32 bit mode ERSTBA_HI before ERSTBA_LO

[Synopsys]- The internal initialization of event ring fetches
the "Event Ring Segment Table Entry" based on the indication of
ERSTBA_LO written.

Signed-off-by: Daehwan Jung <dh10.jung@samsung.com>
---
 drivers/usb/host/xhci-mem.c | 5 ++++-
 drivers/usb/host/xhci.h     | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 3100219..36ee704 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2325,7 +2325,10 @@ xhci_add_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir,
 	erst_base = xhci_read_64(xhci, &ir->ir_set->erst_base);
 	erst_base &= ERST_BASE_RSVDP;
 	erst_base |= ir->erst.erst_dma_addr & ~ERST_BASE_RSVDP;
-	xhci_write_64(xhci, erst_base, &ir->ir_set->erst_base);
+	if (intr_num == 0)
+		xhci_write_64(xhci, erst_base, &ir->ir_set->erst_base);
+	else
+		xhci_write_64_r(xhci, erst_base, &ir->ir_set->erst_base);
 
 	/* Set the event ring dequeue address of this interrupter */
 	xhci_set_hc_event_deq(xhci, ir);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 3041515..7951c0e 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -17,6 +17,7 @@
 #include <linux/kernel.h>
 #include <linux/usb/hcd.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/io-64-nonatomic-hi-lo.h>
 
 /* Code sharing between pci-quirks and xhci hcd */
 #include	"xhci-ext-caps.h"
@@ -1747,6 +1748,11 @@ static inline void xhci_write_64(struct xhci_hcd *xhci,
 {
 	lo_hi_writeq(val, regs);
 }
+static inline void xhci_write_64_r(struct xhci_hcd *xhci,
+				 const u64 val, __le64 __iomem *regs)
+{
+	hi_lo_writeq(val, regs);
+}
 
 static inline int xhci_link_trb_quirk(struct xhci_hcd *xhci)
 {
-- 
2.7.4