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authorWu Zhangjin <wuzhangjin@gmail.com>2010-03-11 11:30:50 +0800
committerRalf Baechle <ralf@linux-mips.org>2010-04-12 17:26:12 +0100
commitb846c10da5d6a5c159ab4dea92c1080d5add9fb1 (patch)
treef02230a549f188f41b7cbd0da25d0b0f70ace7a4 /arch/mips/pci
parent52553664033078102f5f430c861ccd0863b1b708 (diff)
downloadlinux-2.6.34-ux500-b846c10da5d6a5c159ab4dea92c1080d5add9fb1.tar.gz
MIPS: Lemote 2F: Ensure atomic execution of _rdmsr and _wrmsr
On Lemote 2F CS5536 MSRs are accessed through a index / data register pair. The access sequence must be protected by a spinlock to be atomic. Without this rebooting in fs2f_reboot() may fail. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Cc: David Daney <ddaney@caviumnetworks.com> Patchwork: http://patchwork.linux-mips.org/patch/1058/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/pci')
-rw-r--r--arch/mips/pci/ops-loongson2.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/mips/pci/ops-loongson2.c b/arch/mips/pci/ops-loongson2.c
index 2bb4057bf6c..d657ee0bc13 100644
--- a/arch/mips/pci/ops-loongson2.c
+++ b/arch/mips/pci/ops-loongson2.c
@@ -180,15 +180,21 @@ struct pci_ops loongson_pci_ops = {
};
#ifdef CONFIG_CS5536
+DEFINE_RAW_SPINLOCK(msr_lock);
+
void _rdmsr(u32 msr, u32 *hi, u32 *lo)
{
struct pci_bus bus = {
.number = PCI_BUS_CS5536
};
u32 devfn = PCI_DEVFN(PCI_IDSEL_CS5536, 0);
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&msr_lock, flags);
loongson_pcibios_write(&bus, devfn, PCI_MSR_ADDR, 4, msr);
loongson_pcibios_read(&bus, devfn, PCI_MSR_DATA_LO, 4, lo);
loongson_pcibios_read(&bus, devfn, PCI_MSR_DATA_HI, 4, hi);
+ raw_spin_unlock_irqrestore(&msr_lock, flags);
}
EXPORT_SYMBOL(_rdmsr);
@@ -198,9 +204,13 @@ void _wrmsr(u32 msr, u32 hi, u32 lo)
.number = PCI_BUS_CS5536
};
u32 devfn = PCI_DEVFN(PCI_IDSEL_CS5536, 0);
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&msr_lock, flags);
loongson_pcibios_write(&bus, devfn, PCI_MSR_ADDR, 4, msr);
loongson_pcibios_write(&bus, devfn, PCI_MSR_DATA_LO, 4, lo);
loongson_pcibios_write(&bus, devfn, PCI_MSR_DATA_HI, 4, hi);
+ raw_spin_unlock_irqrestore(&msr_lock, flags);
}
EXPORT_SYMBOL(_wrmsr);
#endif