[PATCH v7 2/3] of/pci: Provide support for parsing PCI DT ranges property
Andrew Murray
andrew.murray at arm.com
Fri Apr 19 00:24:34 EST 2013
On Thu, Apr 18, 2013 at 02:44:01PM +0100, Grant Likely wrote:
> 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?
>
Yes I think that would make sense.
> >
> > - /* 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?
Russell King suggested this change - see
https://patchwork.kernel.org/patch/2323941/
>
> 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.
Thanks for the feedback. I'll update the patch in the future.
Andrew Murray
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