Re: [PATCH] powerpc: Use generic pci_mmap_resource_range()

From: Bjorn Helgaas
Date: Wed Feb 28 2018 - 18:07:20 EST


On Mon, Feb 19, 2018 at 12:59:51PM +0000, David Woodhouse wrote:
> Commit f719582435 ("PCI: Add pci_mmap_resource_range() and use it for
> ARM64") added this generic function with the intent of using it
> everywhere and ultimately killing the old arch-specific implementations.
>
> Let's get on with that eradication...
>
> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>

Applied to pci/resource-mmap for v4.17, thanks!

Powerpc folks, let me know if you have applied this or would like to, and
I'll drop it.

> ---
> arch/powerpc/include/asm/pci.h | 9 ++--
> arch/powerpc/kernel/pci-common.c | 106 ++++-----------------------------------
> 2 files changed, 15 insertions(+), 100 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
> index d82802f..401c62a 100644
> --- a/arch/powerpc/include/asm/pci.h
> +++ b/arch/powerpc/include/asm/pci.h
> @@ -76,10 +76,11 @@ extern int pci_proc_domain(struct pci_bus *bus);
>
> struct vm_area_struct;
>
> -/* Tell drivers/pci/proc.c that we have pci_mmap_page_range() and it does WC */
> -#define HAVE_PCI_MMAP 1
> -#define arch_can_pci_mmap_io() 1
> -#define arch_can_pci_mmap_wc() 1
> +/* Tell PCI code what kind of PCI resource mappings we support */
> +#define HAVE_PCI_MMAP 1
> +#define ARCH_GENERIC_PCI_MMAP_RESOURCE 1
> +#define arch_can_pci_mmap_io() 1
> +#define arch_can_pci_mmap_wc() 1
>
> extern int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val,
> size_t count);
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index 446c796..fe9733f 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -410,72 +410,22 @@ static int pci_read_irq_line(struct pci_dev *pci_dev)
> }
>
> /*
> - * Platform support for /proc/bus/pci/X/Y mmap()s,
> - * modelled on the sparc64 implementation by Dave Miller.
> + * Platform support for /proc/bus/pci/X/Y mmap()s.
> * -- paulus.
> */
> -
> -/*
> - * Adjust vm_pgoff of VMA such that it is the physical page offset
> - * corresponding to the 32-bit pci bus offset for DEV requested by the user.
> - *
> - * Basically, the user finds the base address for his device which he wishes
> - * to mmap. They read the 32-bit value from the config space base register,
> - * add whatever PAGE_SIZE multiple offset they wish, and feed this into the
> - * offset parameter of mmap on /proc/bus/pci/XXX for that device.
> - *
> - * Returns negative error code on failure, zero on success.
> - */
> -static struct resource *__pci_mmap_make_offset(struct pci_dev *dev,
> - resource_size_t *offset,
> - enum pci_mmap_state mmap_state)
> +int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma)
> {
> - struct pci_controller *hose = pci_bus_to_host(dev->bus);
> - unsigned long io_offset = 0;
> - int i, res_bit;
> -
> - if (hose == NULL)
> - return NULL; /* should never happen */
> -
> - /* If memory, add on the PCI bridge address offset */
> - if (mmap_state == pci_mmap_mem) {
> -#if 0 /* See comment in pci_resource_to_user() for why this is disabled */
> - *offset += hose->pci_mem_offset;
> -#endif
> - res_bit = IORESOURCE_MEM;
> - } else {
> - io_offset = (unsigned long)hose->io_base_virt - _IO_BASE;
> - *offset += io_offset;
> - res_bit = IORESOURCE_IO;
> - }
> -
> - /*
> - * Check that the offset requested corresponds to one of the
> - * resources of the device.
> - */
> - for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
> - struct resource *rp = &dev->resource[i];
> - int flags = rp->flags;
> + struct pci_controller *hose = pci_bus_to_host(pdev->bus);
> + resource_size_t ioaddr = pci_resource_start(pdev, bar);
>
> - /* treat ROM as memory (should be already) */
> - if (i == PCI_ROM_RESOURCE)
> - flags |= IORESOURCE_MEM;
> -
> - /* Active and same type? */
> - if ((flags & res_bit) == 0)
> - continue;
> -
> - /* In the range of this resource? */
> - if (*offset < (rp->start & PAGE_MASK) || *offset > rp->end)
> - continue;
> + if (!hose)
> + return -EINVAL;
>
> - /* found it! construct the final physical address */
> - if (mmap_state == pci_mmap_io)
> - *offset += hose->io_base_phys - io_offset;
> - return rp;
> - }
> + /* Convert to an offset within this PCI controller */
> + ioaddr -= (unsigned long)hose->io_base_virt - _IO_BASE;
>
> - return NULL;
> + vma->vm_pgoff += (ioaddr + hose->io_base_phys) >> PAGE_SHIFT;
> + return 0;
> }
>
> /*
> @@ -527,42 +477,6 @@ pgprot_t pci_phys_mem_access_prot(struct file *file,
> return prot;
> }
>
> -
> -/*
> - * Perform the actual remap of the pages for a PCI device mapping, as
> - * appropriate for this architecture. The region in the process to map
> - * is described by vm_start and vm_end members of VMA, the base physical
> - * address is found in vm_pgoff.
> - * The pci device structure is provided so that architectures may make mapping
> - * decisions on a per-device or per-bus basis.
> - *
> - * Returns a negative error code on failure, zero on success.
> - */
> -int pci_mmap_page_range(struct pci_dev *dev, int bar,
> - struct vm_area_struct *vma,
> - enum pci_mmap_state mmap_state, int write_combine)
> -{
> - resource_size_t offset =
> - ((resource_size_t)vma->vm_pgoff) << PAGE_SHIFT;
> - struct resource *rp;
> - int ret;
> -
> - rp = __pci_mmap_make_offset(dev, &offset, mmap_state);
> - if (rp == NULL)
> - return -EINVAL;
> -
> - vma->vm_pgoff = offset >> PAGE_SHIFT;
> - if (write_combine)
> - vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);
> - else
> - vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> -
> - ret = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
> - vma->vm_end - vma->vm_start, vma->vm_page_prot);
> -
> - return ret;
> -}
> -
> /* This provides legacy IO read access on a bus */
> int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val, size_t size)
> {
> --
> 2.7.4
>