of/pci: Add pci_register_io_range() and pci_pio_to_address()

Some architectures do not have a simple view of the PCI I/O space and
instead use a range of CPU addresses that map to bus addresses.  For some
architectures these ranges will be expressed by OF bindings in a device
tree file.

This patch introduces a pci_register_io_range() helper function with a
generic implementation that can be used by such architectures to keep track
of the I/O ranges described by the PCI bindings.  If the PCI_IOBASE macro
is not defined, that signals lack of support for PCI and we return an
error.

In order to retrieve the CPU address associated with an I/O port, a new
helper function pci_pio_to_address() is introduced.  This will search in
the list of ranges registered with pci_register_io_range() and return the
CPU address that corresponds to the given port.

[arnd: add dummy !CONFIG_OF pci_pio_to_address() to fix build errors]
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
CC: Grant Likely <grant.likely@linaro.org>

diff --git a/drivers/of/address.c b/drivers/of/address.c
index e3718250d66e4f2b5fcb13c9936b7e28615440ec..758d4f04d4aadd1af51452eb4047d75035ce259c 100644 (file)
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -5,6 +5,8 @@
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/pci_regs.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
 #include <linux/string.h>
 
 /* Max address size we deal with */
@@ -601,12 +603,119 @@ const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
 }
 EXPORT_SYMBOL(of_get_address);
 
+#ifdef PCI_IOBASE
+struct io_range {
+       struct list_head list;
+       phys_addr_t start;
+       resource_size_t size;
+};
+
+static LIST_HEAD(io_range_list);
+static DEFINE_SPINLOCK(io_range_lock);
+#endif
+
+/*
+ * Record the PCI IO range (expressed as CPU physical address + size).
+ * Return a negative value if an error has occured, zero otherwise
+ */
+int __weak pci_register_io_range(phys_addr_t addr, resource_size_t size)
+{
+       int err = 0;
+
+#ifdef PCI_IOBASE
+       struct io_range *range;
+       resource_size_t allocated_size = 0;
+
+       /* check if the range hasn't been previously recorded */
+       spin_lock(&io_range_lock);
+       list_for_each_entry(range, &io_range_list, list) {
+               if (addr >= range->start && addr + size <= range->start + size) {
+                       /* range already registered, bail out */
+                       goto end_register;
+               }
+               allocated_size += range->size;
+       }
+
+       /* range not registed yet, check for available space */
+       if (allocated_size + size - 1 > IO_SPACE_LIMIT) {
+               /* if it's too big check if 64K space can be reserved */
+               if (allocated_size + SZ_64K - 1 > IO_SPACE_LIMIT) {
+                       err = -E2BIG;
+                       goto end_register;
+               }
+
+               size = SZ_64K;
+               pr_warn("Requested IO range too big, new size set to 64K\n");
+       }
+
+       /* add the range to the list */
+       range = kzalloc(sizeof(*range), GFP_KERNEL);
+       if (!range) {
+               err = -ENOMEM;
+               goto end_register;
+       }
+
+       range->start = addr;
+       range->size = size;
+
+       list_add_tail(&range->list, &io_range_list);
+
+end_register:
+       spin_unlock(&io_range_lock);
+#endif
+
+       return err;
+}
+
+phys_addr_t pci_pio_to_address(unsigned long pio)
+{
+       phys_addr_t address = (phys_addr_t)OF_BAD_ADDR;
+
+#ifdef PCI_IOBASE
+       struct io_range *range;
+       resource_size_t allocated_size = 0;
+
+       if (pio > IO_SPACE_LIMIT)
+               return address;
+
+       spin_lock(&io_range_lock);
+       list_for_each_entry(range, &io_range_list, list) {
+               if (pio >= allocated_size && pio < allocated_size + range->size) {
+                       address = range->start + pio - allocated_size;
+                       break;
+               }
+               allocated_size += range->size;
+       }
+       spin_unlock(&io_range_lock);
+#endif
+
+       return address;
+}
+
 unsigned long __weak pci_address_to_pio(phys_addr_t address)
 {
+#ifdef PCI_IOBASE
+       struct io_range *res;
+       resource_size_t offset = 0;
+       unsigned long addr = -1;
+
+       spin_lock(&io_range_lock);
+       list_for_each_entry(res, &io_range_list, list) {
+               if (address >= res->start && address < res->start + res->size) {
+                       addr = res->start - address + offset;
+                       break;
+               }
+               offset += res->size;
+       }
+       spin_unlock(&io_range_lock);
+
+       return addr;
+#else
        if (address > IO_SPACE_LIMIT)
                return (unsigned long)-1;
 
        return (unsigned long) address;
+#endif
 }
 
 static int __of_address_to_resource(struct device_node *dev,

diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index fb7b7221e06309b8cbde7f4b2f996aeff4f77f8e..497a04356ff8df334a6c1b302bfb5dd6a710e031 100644 (file)
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -55,7 +55,9 @@ extern void __iomem *of_iomap(struct device_node *device, int index);
 extern const __be32 *of_get_address(struct device_node *dev, int index,
                           u64 *size, unsigned int *flags);
 
+extern int pci_register_io_range(phys_addr_t addr, resource_size_t size);
 extern unsigned long pci_address_to_pio(phys_addr_t addr);
+extern phys_addr_t pci_pio_to_address(unsigned long pio);
 
 extern int of_pci_range_parser_init(struct of_pci_range_parser *parser,
                        struct device_node *node);
@@ -80,6 +82,11 @@ static inline const __be32 *of_get_address(struct device_node *dev, int index,
        return NULL;
 }
 
+static inline phys_addr_t pci_pio_to_address(unsigned long pio)
+{
+       return 0;
+}
+
 static inline int of_pci_range_parser_init(struct of_pci_range_parser *parser,
                        struct device_node *node)
 {