powerpc/PCI: Add legacy PCI access via sysfs

This patch adds support for legacy_io and legacy_mem files in
bus class directories in sysfs for powerpc

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 153 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index ae2ea803a0f2..9047af7baa69 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h
@@ -74,6 +74,13 @@ struct pci_controller {
         unsigned long pci_io_size;
 #endif
 
+        /* Some machines have a special region to forward the ISA
+         * "memory" cycles such as VGA memory regions. Left to 0
+         * if unsupported
+         */
+        resource_size_t isa_mem_phys;
+        resource_size_t isa_mem_size;
+
         struct pci_ops *ops;
         unsigned int __iomem *cfg_addr;
         void __iomem *cfg_data;
diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
index 0e52c7828ea4..39d547fde956 100644
--- a/arch/powerpc/include/asm/pci.h
+++ b/arch/powerpc/include/asm/pci.h
@@ -123,6 +123,16 @@ int pci_mmap_page_range(struct pci_dev *pdev, struct vm_area_struct *vma,
 /* Tell drivers/pci/proc.c that we have pci_mmap_page_range() */
 #define HAVE_PCI_MMAP   1
 
+extern int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val,
+                           size_t count);
+extern int pci_legacy_write(struct pci_bus *bus, loff_t port, u32 val,
+                           size_t count);
+extern int pci_mmap_legacy_page_range(struct pci_bus *bus,
+                                      struct vm_area_struct *vma,
+                                      enum pci_mmap_state mmap_state);
+
+#define HAVE_PCI_LEGACY 1
+
 #if defined(CONFIG_PPC64) || defined(CONFIG_NOT_COHERENT_CACHE)
 /*
  * For 64-bit kernels, pci_unmap_{single,page} is not a nop.
@@ -226,5 +236,6 @@ extern void pci_resource_to_user(const struct pci_dev *dev, int bar,
 extern void pcibios_do_bus_setup(struct pci_bus *bus);
 extern void pcibios_fixup_of_probed_bus(struct pci_bus *bus);
 
+
 #endif  /* __KERNEL__ */
 #endif /* __ASM_POWERPC_PCI_H */
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 01ce8c38bae6..3815d84a1ef4 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -451,7 +451,8 @@ pgprot_t pci_phys_mem_access_prot(struct file *file,
                 pci_dev_put(pdev);
         }
 
-        DBG("non-PCI map for %lx, prot: %lx\n", offset, prot);
+        DBG("non-PCI map for %llx, prot: %lx\n",
+            (unsigned long long)offset, prot);
 
         return __pgprot(prot);
 }
@@ -490,6 +491,131 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
         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)
+{
+        unsigned long offset;
+        struct pci_controller *hose = pci_bus_to_host(bus);
+        struct resource *rp = &hose->io_resource;
+        void __iomem *addr;
+
+        /* Check if port can be supported by that bus. We only check
+         * the ranges of the PHB though, not the bus itself as the rules
+         * for forwarding legacy cycles down bridges are not our problem
+         * here. So if the host bridge supports it, we do it.
+         */
+        offset = (unsigned long)hose->io_base_virt - _IO_BASE;
+        offset += port;
+
+        if (!(rp->flags & IORESOURCE_IO))
+                return -ENXIO;
+        if (offset < rp->start || (offset + size) > rp->end)
+                return -ENXIO;
+        addr = hose->io_base_virt + port;
+
+        switch(size) {
+        case 1:
+                *((u8 *)val) = in_8(addr);
+                return 1;
+        case 2:
+                if (port & 1)
+                        return -EINVAL;
+                *((u16 *)val) = in_le16(addr);
+                return 2;
+        case 4:
+                if (port & 3)
+                        return -EINVAL;
+                *((u32 *)val) = in_le32(addr);
+                return 4;
+        }
+        return -EINVAL;
+}
+
+/* This provides legacy IO write access on a bus */
+int pci_legacy_write(struct pci_bus *bus, loff_t port, u32 val, size_t size)
+{
+        unsigned long offset;
+        struct pci_controller *hose = pci_bus_to_host(bus);
+        struct resource *rp = &hose->io_resource;
+        void __iomem *addr;
+
+        /* Check if port can be supported by that bus. We only check
+         * the ranges of the PHB though, not the bus itself as the rules
+         * for forwarding legacy cycles down bridges are not our problem
+         * here. So if the host bridge supports it, we do it.
+         */
+        offset = (unsigned long)hose->io_base_virt - _IO_BASE;
+        offset += port;
+
+        if (!(rp->flags & IORESOURCE_IO))
+                return -ENXIO;
+        if (offset < rp->start || (offset + size) > rp->end)
+                return -ENXIO;
+        addr = hose->io_base_virt + port;
+
+        /* WARNING: The generic code is idiotic. It gets passed a pointer
+         * to what can be a 1, 2 or 4 byte quantity and always reads that
+         * as a u32, which means that we have to correct the location of
+         * the data read within those 32 bits for size 1 and 2
+         */
+        switch(size) {
+        case 1:
+                out_8(addr, val >> 24);
+                return 1;
+        case 2:
+                if (port & 1)
+                        return -EINVAL;
+                out_le16(addr, val >> 16);
+                return 2;
+        case 4:
+                if (port & 3)
+                        return -EINVAL;
+                out_le32(addr, val);
+                return 4;
+        }
+        return -EINVAL;
+}
+
+/* This provides legacy IO or memory mmap access on a bus */
+int pci_mmap_legacy_page_range(struct pci_bus *bus,
+                               struct vm_area_struct *vma,
+                               enum pci_mmap_state mmap_state)
+{
+        struct pci_controller *hose = pci_bus_to_host(bus);
+        resource_size_t offset =
+                ((resource_size_t)vma->vm_pgoff) << PAGE_SHIFT;
+        resource_size_t size = vma->vm_end - vma->vm_start;
+        struct resource *rp;
+
+        pr_debug("pci_mmap_legacy_page_range(%04x:%02x, %s @%llx..%llx)\n",
+                 pci_domain_nr(bus), bus->number,
+                 mmap_state == pci_mmap_mem ? "MEM" : "IO",
+                 (unsigned long long)offset,
+                 (unsigned long long)(offset + size - 1));
+
+        if (mmap_state == pci_mmap_mem) {
+                if ((offset + size) > hose->isa_mem_size)
+                        return -ENXIO;
+                offset += hose->isa_mem_phys;
+        } else {
+                unsigned long io_offset = (unsigned long)hose->io_base_virt - _IO_BASE;
+                unsigned long roffset = offset + io_offset;
+                rp = &hose->io_resource;
+                if (!(rp->flags & IORESOURCE_IO))
+                        return -ENXIO;
+                if (roffset < rp->start || (roffset + size) > rp->end)
+                        return -ENXIO;
+                offset += hose->io_base_phys;
+        }
+        pr_debug(" -> mapping phys %llx\n", (unsigned long long)offset);
+
+        vma->vm_pgoff = offset >> PAGE_SHIFT;
+        vma->vm_page_prot |= _PAGE_NO_CACHE | _PAGE_GUARDED;
+        return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
+                               vma->vm_end - vma->vm_start,
+                               vma->vm_page_prot);
+}
+
 void pci_resource_to_user(const struct pci_dev *dev, int bar,
                           const struct resource *rsrc,
                           resource_size_t *start, resource_size_t *end)
@@ -592,6 +718,12 @@ void __devinit pci_process_bridge_OF_ranges(struct pci_controller *hose,
                 cpu_addr = of_translate_address(dev, ranges + 3);
                 size = of_read_number(ranges + pna + 3, 2);
                 ranges += np;
+
+                /* If we failed translation or got a zero-sized region
+                 * (some FW try to feed us with non sensical zero sized regions
+                 * such as power3 which look like some kind of attempt at exposing
+                 * the VGA memory hole)
+                 */
                 if (cpu_addr == OF_BAD_ADDR || size == 0)
                         continue;
 
@@ -665,6 +797,8 @@ void __devinit pci_process_bridge_OF_ranges(struct pci_controller *hose,
                                 isa_hole = memno;
                                 if (primary || isa_mem_base == 0)
                                         isa_mem_base = cpu_addr;
+                                hose->isa_mem_phys = cpu_addr;
+                                hose->isa_mem_size = size;
                         }
 
                         /* We get the PCI/Mem offset from the first range or