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Subject[PATCH v10 10/10] PCI: Introduce pci_remap_iospace() for remapping PCI I/O bus resources into CPU space
Date
Introduce a default implementation for remapping PCI bus I/O resources
onto the CPU address space. Architectures with special needs may
provide their own version, but most should be able to use this one.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
---
drivers/pci/pci.c | 33 +++++++++++++++++++++++++++++++++
include/asm-generic/pgtable.h | 4 ++++
include/linux/pci.h | 3 +++
3 files changed, 40 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 2c9ac70..654b44c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2704,6 +2704,39 @@ int pci_request_regions_exclusive(struct pci_dev *pdev, const char *res_name)
}
EXPORT_SYMBOL(pci_request_regions_exclusive);

+/**
+ * pci_remap_iospace - Remap the memory mapped I/O space
+ * @res: Resource describing the I/O space
+ * @phys_addr: physical address where the range will be mapped.
+ *
+ * Remap the memory mapped I/O space described by the @res
+ * into the CPU physical address space. Only architectures
+ * that have memory mapped IO defined (and hence PCI_IOBASE)
+ * should call this function.
+ */
+int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
+{
+ int err = -ENODEV;
+
+#ifdef PCI_IOBASE
+ if (!(res->flags & IORESOURCE_IO))
+ return -EINVAL;
+
+ if (res->end > IO_SPACE_LIMIT)
+ return -EINVAL;
+
+ err = ioremap_page_range(res->start + (unsigned long)PCI_IOBASE,
+ res->end + 1 + (unsigned long)PCI_IOBASE,
+ phys_addr, pgprot_device(PAGE_KERNEL));
+#else
+ /* this architecture does not have memory mapped I/O space,
+ so this function should never be called */
+ WARN_ON(1);
+#endif
+
+ return err;
+}
+
static void __pci_set_master(struct pci_dev *dev, bool enable)
{
u16 old_cmd, cmd;
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 53b2acc..977e545 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -249,6 +249,10 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
#define pgprot_writecombine pgprot_noncached
#endif

+#ifndef pgprot_device
+#define pgprot_device pgprot_noncached
+#endif
+
/*
* When walking page tables, get the address of the next boundary,
* or the end address of the range if that comes earlier. Although no
diff --git a/include/linux/pci.h b/include/linux/pci.h
index a494e5d..fc8c529 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1100,6 +1100,9 @@ int __must_check pci_bus_alloc_resource(struct pci_bus *bus,
resource_size_t),
void *alignf_data);

+
+int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
+
static inline dma_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
{
struct pci_bus_region region;
--
2.0.4


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