From 41f8bba7f5552d033583777dede2df7c36e7853d Mon Sep 17 00:00:00 2001 From: Liviu Dudau Date: Mon, 29 Sep 2014 15:29:21 +0100 Subject: [PATCH] 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 Signed-off-by: Bjorn Helgaas Reviewed-by: Catalin Marinas Acked-by: Rob Herring CC: Grant Likely --- drivers/of/address.c | 109 +++++++++++++++++++++++++++++++++++++ include/linux/of_address.h | 7 +++ 2 files changed, 116 insertions(+) diff --git a/drivers/of/address.c b/drivers/of/address.c index e3718250d66e..758d4f04d4aa 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -5,6 +5,8 @@ #include #include #include +#include +#include #include /* 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 fb7b7221e063..497a04356ff8 100644 --- 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) {