diff options
| author | Wu Zhangjin <wuzhangjin@gmail.com> | 2010-03-11 04:30:50 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2010-04-12 18:26:12 +0200 |
| commit | b846c10da5d6a5c159ab4dea92c1080d5add9fb1 (patch) | |
| tree | f02230a549f188f41b7cbd0da25d0b0f70ace7a4 /arch/mips | |
| parent | MIPS: Initialize an atomic_t properly with ATOMIC_INIT(0). (diff) | |
| download | linux-b846c10da5d6a5c159ab4dea92c1080d5add9fb1.tar.xz linux-b846c10da5d6a5c159ab4dea92c1080d5add9fb1.zip | |
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')
| -rw-r--r-- | arch/mips/pci/ops-loongson2.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/mips/pci/ops-loongson2.c b/arch/mips/pci/ops-loongson2.c index 2bb4057bf6c7..d657ee0bc131 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 |