[PATCH v7 2/3] of/pci: Provide support for parsing PCI DT ranges property
Grant Likely
grant.likely at secretlab.ca
Thu Apr 18 23:44:01 EST 2013
On Tue, 16 Apr 2013 11:18:27 +0100, Andrew Murray <Andrew.Murray at arm.com> wrote:
> This patch factors out common implementation patterns to reduce overall kernel
> code and provide a means for host bridge drivers to directly obtain struct
> resources from the DT's ranges property without relying on architecture specific
> DT handling. This will make it easier to write archiecture independent host bridge
> drivers and mitigate against further duplication of DT parsing code.
>
> This patch can be used in the following way:
>
> struct of_pci_range_parser parser;
> struct of_pci_range range;
>
> if (of_pci_range_parser(&parser, np))
> ; //no ranges property
>
> for_each_of_pci_range(&parser, &range) {
>
> /*
> directly access properties of the address range, e.g.:
> range.pci_space, range.pci_addr, range.cpu_addr,
> range.size, range.flags
>
> alternatively obtain a struct resource, e.g.:
> struct resource res;
> of_pci_range_to_resource(&range, np, &res);
> */
> }
>
> Additionally the implementation takes care of adjacent ranges and merges them
> into a single range (as was the case with powerpc and microblaze).
>
> Signed-off-by: Andrew Murray <Andrew.Murray at arm.com>
> Signed-off-by: Liviu Dudau <Liviu.Dudau at arm.com>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> Reviewed-by: Rob Herring <rob.herring at calxeda.com>
> Tested-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> Tested-by: Linus Walleij <linus.walleij at linaro.org>
Acked-by: Grant Likely <grant.likely at secretlab.ca>
But comments below...
> ---
> drivers/of/address.c | 67 ++++++++++++++++++++++++++
> drivers/of/of_pci.c | 113 ++++++++++++++++----------------------------
> include/linux/of_address.h | 46 ++++++++++++++++++
> 3 files changed, 154 insertions(+), 72 deletions(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 04da786..6eec70c 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -227,6 +227,73 @@ int of_pci_address_to_resource(struct device_node *dev, int bar,
> return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
> }
> EXPORT_SYMBOL_GPL(of_pci_address_to_resource);
> +
> +int of_pci_range_parser(struct of_pci_range_parser *parser,
> + struct device_node *node)
> +{
> + const int na = 3, ns = 2;
> + int rlen;
> +
> + parser->node = node;
> + parser->pna = of_n_addr_cells(node);
> + parser->np = parser->pna + na + ns;
> +
> + parser->range = of_get_property(node, "ranges", &rlen);
> + if (parser->range == NULL)
> + return -ENOENT;
> +
> + parser->end = parser->range + rlen / sizeof(__be32);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(of_pci_range_parser);
"of_pci_range_parser_init" would be a clearer name
> +struct of_pci_range *of_pci_process_ranges(struct of_pci_range_parser *parser,
> + struct of_pci_range *range)
Similarly, "of_pci_range_parser_one" would be more consistent.
> +{
> + const int na = 3, ns = 2;
> +
> + if (!range)
> + return NULL;
> +
> + if (!parser->range || parser->range + parser->np > parser->end)
> + return NULL;
> +
> + range->pci_space = parser->range[0];
> + range->flags = of_bus_pci_get_flags(parser->range);
> + range->pci_addr = of_read_number(parser->range + 1, ns);
> + range->cpu_addr = of_translate_address(parser->node,
> + parser->range + na);
> + range->size = of_read_number(parser->range + parser->pna + na, ns);
> +
> + parser->range += parser->np;
> +
> + /* Now consume following elements while they are contiguous */
> + while (parser->range + parser->np <= parser->end) {
> + u32 flags, pci_space;
> + u64 pci_addr, cpu_addr, size;
> +
> + pci_space = be32_to_cpup(parser->range);
> + flags = of_bus_pci_get_flags(parser->range);
> + pci_addr = of_read_number(parser->range + 1, ns);
> + cpu_addr = of_translate_address(parser->node,
> + parser->range + na);
> + size = of_read_number(parser->range + parser->pna + na, ns);
> +
> + if (flags != range->flags)
> + break;
> + if (pci_addr != range->pci_addr + range->size ||
> + cpu_addr != range->cpu_addr + range->size)
> + break;
> +
> + range->size += size;
> + parser->range += parser->np;
> + }
> +
> + return range;
> +}
> +EXPORT_SYMBOL_GPL(of_pci_process_ranges);
> +
> #endif /* CONFIG_PCI */
>
> /*
> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> index 1626172..e5ab604 100644
> --- a/drivers/of/of_pci.c
> +++ b/drivers/of/of_pci.c
> @@ -2,6 +2,7 @@
> #include <linux/export.h>
> #include <linux/of.h>
> #include <linux/of_pci.h>
> +#include <linux/of_address.h>
> #include <asm/prom.h>
>
> #if defined(CONFIG_PPC32) || defined(CONFIG_PPC64) || defined(CONFIG_MICROBLAZE)
> @@ -82,67 +83,43 @@ EXPORT_SYMBOL_GPL(of_pci_find_child_device);
> void pci_process_bridge_OF_ranges(struct pci_controller *hose,
> struct device_node *dev, int primary)
> {
> - const u32 *ranges;
> - int rlen;
> - int pna = of_n_addr_cells(dev);
> - int np = pna + 5;
> int memno = 0, isa_hole = -1;
> - u32 pci_space;
> - unsigned long long pci_addr, cpu_addr, pci_next, cpu_next, size;
> unsigned long long isa_mb = 0;
> struct resource *res;
> + struct of_pci_range range;
> + struct of_pci_range_parser parser;
> + u32 res_type;
>
> pr_info("PCI host bridge %s %s ranges:\n",
> dev->full_name, primary ? "(primary)" : "");
>
> - /* Get ranges property */
> - ranges = of_get_property(dev, "ranges", &rlen);
> - if (ranges == NULL)
> + /* Check for ranges property */
> + if (of_pci_range_parser(&parser, dev))
> return;
>
> - /* Parse it */
> pr_debug("Parsing ranges property...\n");
> - while ((rlen -= np * 4) >= 0) {
> + for_each_of_pci_range(&parser, &range) {
> /* Read next ranges element */
> - pci_space = ranges[0];
> - pci_addr = of_read_number(ranges + 1, 2);
> - cpu_addr = of_translate_address(dev, ranges + 3);
> - size = of_read_number(ranges + pna + 3, 2);
Tip: the diff on this function would be a whole lot simpler if the
above locals were kept, but updated from the ranges structure. Not at
all a big problem, but it is something that makes changes like this
easier to review. The removal of the locals could also be split into a
separate patch to end up with the same result.
> -
> - pr_debug("pci_space: 0x%08x pci_addr:0x%016llx ",
> - pci_space, pci_addr);
> - pr_debug("cpu_addr:0x%016llx size:0x%016llx\n",
> - cpu_addr, size);
> -
> - ranges += np;
> + pr_debug("pci_space: 0x%08x pci_addr: 0x%016llx ",
> + range.pci_space, range.pci_addr);
> + pr_debug("cpu_addr: 0x%016llx size: 0x%016llx\n",
> + range.cpu_addr, range.size);
Nit: the patch changed whitespace on the pr_debug() statements, so even
though the first line of each is identical, they look different in the
patch.
>
> /* 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)
> + if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
> continue;
Can this also be rolled into the parsing iterator?
>
> - /* Now consume following elements while they are contiguous */
> - for (; rlen >= np * sizeof(u32);
> - ranges += np, rlen -= np * 4) {
> - if (ranges[0] != pci_space)
> - break;
> - pci_next = of_read_number(ranges + 1, 2);
> - cpu_next = of_translate_address(dev, ranges + 3);
> - if (pci_next != pci_addr + size ||
> - cpu_next != cpu_addr + size)
> - break;
> - size += of_read_number(ranges + pna + 3, 2);
> - }
> -
> /* Act based on address space type */
> res = NULL;
> - switch ((pci_space >> 24) & 0x3) {
> - case 1: /* PCI IO space */
> + res_type = range.flags & IORESOURCE_TYPE_BITS;
> + if (res_type == IORESOURCE_IO) {
Why the change from switch() to an if/else if sequence?
But those are mostly nitpicks. If this is deferred to v3.10 then I would
suggest fixing them up and posting for another round of review.
g.
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