On 4/7/2016 12:00 PM, Bjorn Helgaas wrote:
> Hi Sinan,
>
> On Mon, Mar 07, 2016 at 05:21:49PM -0500, Sinan Kaya wrote:
>> The PCI_IOBASE needs to be released after hotplug removal so that it can be
>> re-added back by the pci_remap_iospace function during insertion.
>>
>> Adding unmap function to follow IO remap function.
>>
>> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
>> ---
>> drivers/pci/pci.c | 25 +++++++++++++++++++++++++
>> include/linux/pci.h | 1 +
>> 2 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index 3a516c0..f5faed2 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -26,6 +26,7 @@
>> #include <linux/device.h>
>> #include <linux/pm_runtime.h>
>> #include <linux/pci_hotplug.h>
>> +#include <linux/vmalloc.h>
>> #include <asm-generic/pci-bridge.h>
>> #include <asm/setup.h>
>> #include <linux/aer.h>
>> @@ -3169,6 +3170,30 @@ int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
>> #endif
>> }
>>
>> +/**
>> + * pci_unmap_iospace - Unmap the memory mapped I/O space
>> + * @virt_addr: virtual address to be unmapped
>> + * @size: size of the physical address to be unmapped
>> + *
>> + * Unmap the CPU virtual address @virt_addr from virtual address space.
>> + * Only architectures that have memory mapped IO functions defined
>> + * (and the PCI_IOBASE value defined) should call this function.
>> + */
>> +void __weak pci_unmap_iospace(struct resource *res)
>
> Why is this weak? I assume probably because pci_remap_iospace() is
> weak, but I don't see any reason why *that* needs to be weak. There's
> only one implementation. I think neither one should be weak unless we
> have an actual need for that.
>
Right, copy paste mistake. Even the function parameter description above
is not right.
I can get rid of the __weak from both on the next iteration.
>> +{
>> +#if defined(PCI_IOBASE) && defined(CONFIG_MMU)
>> + unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
>> +
>> + unmap_kernel_range(vaddr, resource_size(res));
>
> There really aren't any other generic uses of unmap_kernel_range().
> This isn't an unusual scenario, so I would expect this code to use a
> pattern that's used elsewhere.
OK, What's the best way to remove a mapping? I'm open for suggestions.
I copied this pattern from GHES driver.
>
>> +#else
>> + /*
>> + * This architecture does not have memory mapped I/O space,
>> + * so this function should never be called.
>> + */
>> + WARN_ONCE(1, "This architecture does not support memory mapped I/O\n");
>> +#endif
>> +}
>> +
>> static void __pci_set_master(struct pci_dev *dev, bool enable)
>> {
>> u16 old_cmd, cmd;
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index 398ae7e..c6e3f0e 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -1172,6 +1172,7 @@ int pci_register_io_range(phys_addr_t addr, resource_size_t size);
>> unsigned long pci_address_to_pio(phys_addr_t addr);
>> phys_addr_t pci_pio_to_address(unsigned long pio);
>> int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
>> +void pci_unmap_iospace(struct resource *res);
>>
>> static inline pci_bus_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
>> {
>> --
>> 1.8.2.1
>>
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--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
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