linux-kernel - [PATCH 3/5 v4] usb: pci-quirks: Protect the I/O port pair of SB800

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Date:   Thu, 22 Jun 2017 15:21:32 +0200
From:   Zoltán Böszörményi 
        <zboszor@...hu>
To:     linux-kernel@...r.kernel.org
Cc:     linux-usb@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-i2c@...r.kernel.org,
        Paul Menzel <paulepanter@...rs.sourceforge.net>,
        Christian Fetzer <fetzer.ch@...il.com>,
        Jean Delvare <jdelvare@...e.com>,
        Nehal Shah <nehal-bakulchandra.shah@....com>,
        Tim Small <tim@...ss.co.uk>,
        Guenter Roeck <linux@...ck-us.net>, kernel@...ss.net,
        wim@...ana.be, jlayton@...chiereds.net, marc.2377@...il.com,
        cshorler@...glemail.com, wsa@...-dreams.de,
        regressions@...mhuis.info,
        Zoltán Böszörményi 
        <zboszor@...hu>
Subject: [PATCH 3/5 v4] usb: pci-quirks: Protect the I/O port pair of SB800

This patch uses the previously introduced macro called
request_declared_muxed_region() to synchronize access to
the I/O port pair 0xcd6 / 0xcd7 on SB800.

These I/O ports are also used by i2c-piix4 and sp5100_tco,
so synchronization is necessary. The other drivers will also
be modified to use the new macro in subsequest patched.

v1: Started with a common mutex in a C source file.

v2: Declared the common mutex in drivers/usb/host/pci-quirks.c
    instead of in a common C file.

v3: Switched to using the new request_declared_muxed_region
    macro.

v4: Fixed checkpatch.pl warnings and use the new
    release_declared_region() macro.

Signed-off-by: Zoltán Böszörményi <zboszor@...hu>
---
 drivers/usb/host/pci-quirks.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index a9a1e4c..593942a 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -279,6 +279,8 @@ bool usb_amd_prefetch_quirk(void)
 }
 EXPORT_SYMBOL_GPL(usb_amd_prefetch_quirk);
 
+static struct resource sb800_res = DEFINE_RES_IO_NAMED(0xcd6, 2, "SB800 USB");
+
 /*
  * The hardware normally enables the A-link power management feature, which
  * lets the system lower the power consumption in idle states.
@@ -314,11 +316,13 @@ static void usb_amd_quirk_pll(int disable)
 	if (amd_chipset.sb_type.gen == AMD_CHIPSET_SB800 ||
 			amd_chipset.sb_type.gen == AMD_CHIPSET_HUDSON2 ||
 			amd_chipset.sb_type.gen == AMD_CHIPSET_BOLTON) {
+		request_declared_muxed_region(&sb800_res);
 		outb_p(AB_REG_BAR_LOW, 0xcd6);
 		addr_low = inb_p(0xcd7);
 		outb_p(AB_REG_BAR_HIGH, 0xcd6);
 		addr_high = inb_p(0xcd7);
 		addr = addr_high << 8 | addr_low;
+		release_declared_region(&sb800_res);
 
 		outl_p(0x30, AB_INDX(addr));
 		outl_p(0x40, AB_DATA(addr));
-- 
2.9.4