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SubjectRe: [PATCH v3 5/5] pci: Add support for creating a generic host_bridge from device tree
On Fri, Feb 28, 2014 at 06:07:05PM -0800, Tanmay Inamdar wrote:
> Earlier email did not deliver to mailing lists because of plain text
> setting problem on my side. Apologies for spamming. Sending it again.
>
> Hello Liviu,
>

Hello Tanmay,

> While porting X-Gene PCIe driver to v2 series, following problems were observed.

Thanks for trying it out.

>
> 1. In 'of_create_pci_host_bridge' function, bus_range is defined
> locally. So, while walking over list of resources in bridge->windows
> later, during X-Gene controller related setup, garbage values are
> found in the resource. Please allocate it dynamically.

Bah, sorry for that. Will fix.

>
> 2. 'domain_nr' problem is partially solved. There are still some
> places where functions are getting invalid domain_nr. For example,
> 'pci_alloc_child_bus' tries to get domain_nr when bridge is not
> assigned to bus. You may want to look for all the places where
> pci_domain_nr is used. Please see below dump -->
>
> pci 0001:00:00.0: scanning [bus 00-00] behind bridge, pass 1
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at
> /home/tinamdar/work/open-source/linux/fs/sysfs/dir.c:52
> sysfs_warn_dup+0x80/0xc0()
> sysfs: cannot create duplicate filename '/class/pci_bus/0000:01'
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc4+ #37
> Call trace:
> [<ffffffc000088140>] dump_backtrace+0x0/0x140
> [<ffffffc000088294>] show_stack+0x14/0x20
> [<ffffffc0004f64b0>] dump_stack+0x78/0xc4
> [<ffffffc000096c88>] warn_slowpath_common+0x88/0xc0
> [<ffffffc000096d10>] warn_slowpath_fmt+0x50/0x60
> [<ffffffc0001b8260>] sysfs_warn_dup+0x80/0xc0
> [<ffffffc0001b8718>] sysfs_do_create_link_sd.isra.2+0xf8/0x100
> [<ffffffc0001b8740>] sysfs_create_link+0x20/0x40
> [<ffffffc000322f5c>] device_add+0x41c/0x520
> [<ffffffc00032307c>] device_register+0x1c/0x40
> [<ffffffc0004f1924>] pci_add_new_bus+0x284/0x380
> [<ffffffc0002c51a0>] pci_scan_bridge+0x4e0/0x540
> [<ffffffc0002c52b4>] pci_scan_child_bus+0xb4/0x140
> [<ffffffc0004f1a34>] pci_rescan_bus+0x14/0x40
> [<ffffffc0006a12d4>] xgene_pcie_probe_bridge+0x688/0x750
> [<ffffffc000327c64>] platform_drv_probe+0x24/0x60
> [<ffffffc000325d74>] really_probe+0xf4/0x220
> [<ffffffc000325fc4>] __driver_attach+0xa4/0xc0
> [<ffffffc000323e18>] bus_for_each_dev+0x58/0xa0
> [<ffffffc000325800>] driver_attach+0x20/0x40
> [<ffffffc0003253d0>] bus_add_driver+0x150/0x220
> [<ffffffc000326780>] driver_register+0x60/0x120
> [<ffffffc000327c20>] __platform_driver_register+0x60/0x80
> [<ffffffc0006a0c44>] xgene_pcie_driver_init+0x18/0x20
> [<ffffffc0000814c4>] do_one_initcall+0xe4/0x160

do you have your xgene_pcie_driver_init being called out of some subsys_initcall?
If so, remove it and let the generic DT parsing code match your driver. The
bridge should've been associated with the root bus by the time the child busses
are scanned and allocated, unless I'm missing something obvious.

Also, can you share your version of your driver with me?

Best regards,
Liviu

> [<ffffffc00068c938>] kernel_init_freeable+0x138/0x1d8
> [<ffffffc0004f06b0>] kernel_init+0x10/0xe0
> ---[ end trace 53db1c3a7fbdeb88 ]---
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at
> /home/tinamdar/work/open-source/linux/drivers/pci/probe.c:711
> pci_add_new_bus+0x36c/0x380()
>
> Thanks,
> Tanmay
>
> On Fri, Feb 28, 2014 at 6:01 PM, Tanmay Inamdar <tinamdar@apm.com> wrote:
> > Hello Liviu,
> >
> > While porting X-Gene PCIe driver to v2 series, following problems were
> > observed.
> >
> > 1. In 'of_create_pci_host_bridge' function, bus_range is defined locally.
> > So, while walking over list of resources in bridge->windows later, during
> > X-Gene controller related setup, garbage values are found in the resource.
> > Please allocate it dynamically.
> >
> > 2. 'domain_nr' problem is partially solved. There are still some places
> > where functions are getting invalid domain_nr. For example,
> > 'pci_alloc_child_bus' tries to get domain_nr when bridge is not assigned to
> > bus. You may want to look for all the places where pci_domain_nr is used.
> > Please see below dump -->
> >
> > pci 0001:00:00.0: scanning [bus 00-00] behind bridge, pass 1
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 1 at
> > /home/tinamdar/work/open-source/linux/fs/sysfs/dir.c:52
> > sysfs_warn_dup+0x80/0xc0()
> > sysfs: cannot create duplicate filename '/class/pci_bus/0000:01'
> > Modules linked in:
> > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc4+ #37
> > Call trace:
> > [<ffffffc000088140>] dump_backtrace+0x0/0x140
> > [<ffffffc000088294>] show_stack+0x14/0x20
> > [<ffffffc0004f64b0>] dump_stack+0x78/0xc4
> > [<ffffffc000096c88>] warn_slowpath_common+0x88/0xc0
> > [<ffffffc000096d10>] warn_slowpath_fmt+0x50/0x60
> > [<ffffffc0001b8260>] sysfs_warn_dup+0x80/0xc0
> > [<ffffffc0001b8718>] sysfs_do_create_link_sd.isra.2+0xf8/0x100
> > [<ffffffc0001b8740>] sysfs_create_link+0x20/0x40
> > [<ffffffc000322f5c>] device_add+0x41c/0x520
> > [<ffffffc00032307c>] device_register+0x1c/0x40
> > [<ffffffc0004f1924>] pci_add_new_bus+0x284/0x380
> > [<ffffffc0002c51a0>] pci_scan_bridge+0x4e0/0x540
> > [<ffffffc0002c52b4>] pci_scan_child_bus+0xb4/0x140
> > [<ffffffc0004f1a34>] pci_rescan_bus+0x14/0x40
> > [<ffffffc0006a12d4>] xgene_pcie_probe_bridge+0x688/0x750
> > [<ffffffc000327c64>] platform_drv_probe+0x24/0x60
> > [<ffffffc000325d74>] really_probe+0xf4/0x220
> > [<ffffffc000325fc4>] __driver_attach+0xa4/0xc0
> > [<ffffffc000323e18>] bus_for_each_dev+0x58/0xa0
> > [<ffffffc000325800>] driver_attach+0x20/0x40
> > [<ffffffc0003253d0>] bus_add_driver+0x150/0x220
> > [<ffffffc000326780>] driver_register+0x60/0x120
> > [<ffffffc000327c20>] __platform_driver_register+0x60/0x80
> > [<ffffffc0006a0c44>] xgene_pcie_driver_init+0x18/0x20
> > [<ffffffc0000814c4>] do_one_initcall+0xe4/0x160
> > [<ffffffc00068c938>] kernel_init_freeable+0x138/0x1d8
> > [<ffffffc0004f06b0>] kernel_init+0x10/0xe0
> > ---[ end trace 53db1c3a7fbdeb88 ]---
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 1 at
> > /home/tinamdar/work/open-source/linux/drivers/pci/probe.c:711
> > pci_add_new_bus+0x36c/0x380()
> >
> > Thanks,
> > Tanmay
> >
> >
> >
> > On Fri, Feb 28, 2014 at 5:08 AM, Liviu Dudau <Liviu.Dudau@arm.com> wrote:
> >>
> >> Several platforms use a rather generic version of parsing
> >> the device tree to find the host bridge ranges. Move the common code
> >> into the generic PCI code and use it to create a pci_host_bridge
> >> structure that can be used by arch code.
> >>
> >> Based on early attempts by Andrew Murray to unify the code.
> >> Used powerpc and microblaze PCI code as starting point.
> >>
> >> Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> >>
> >> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
> >> index 06ace62..feb8436 100644
> >> --- a/drivers/pci/host-bridge.c
> >> +++ b/drivers/pci/host-bridge.c
> >> @@ -6,9 +6,13 @@
> >> #include <linux/init.h>
> >> #include <linux/pci.h>
> >> #include <linux/module.h>
> >> +#include <linux/of_address.h>
> >> +#include <linux/of_pci.h>
> >>
> >> #include "pci.h"
> >>
> >> +static int domain_nr;
> >> +
> >> static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
> >> {
> >> while (bus->parent)
> >> @@ -91,3 +95,133 @@ void pcibios_bus_to_resource(struct pci_bus *bus,
> >> struct resource *res,
> >> res->end = region->end + offset;
> >> }
> >> EXPORT_SYMBOL(pcibios_bus_to_resource);
> >> +
> >> +/**
> >> + * pci_host_bridge_of_get_ranges - Parse PCI host bridge resources from
> >> DT
> >> + * @dev: device node of the host bridge having the range property
> >> + * @resources: list where the range of resources will be added after DT
> >> parsing
> >> + * @io_base: pointer to a variable that will contain the physical address
> >> for
> >> + * the start of the I/O range.
> >> + *
> >> + * If this function returns an error then the @resources list will be
> >> freed.
> >> + *
> >> + * This function will parse the "ranges" property of a PCI host bridge
> >> device
> >> + * node and setup the resource mapping based on its content. It is
> >> expected
> >> + * that the property conforms with the Power ePAPR document.
> >> + *
> >> + * Each architecture is then offered the chance of applying their own
> >> + * filtering of pci_host_bridge_windows based on their own restrictions
> >> by
> >> + * calling pcibios_fixup_bridge_ranges(). The filtered list of windows
> >> + * can then be used when creating a pci_host_bridge structure.
> >> + */
> >> +static int pci_host_bridge_of_get_ranges(struct device_node *dev,
> >> + struct list_head *resources, resource_size_t *io_base)
> >> +{
> >> + struct resource *res;
> >> + struct of_pci_range range;
> >> + struct of_pci_range_parser parser;
> >> + int err;
> >> +
> >> + pr_info("PCI host bridge %s ranges:\n", dev->full_name);
> >> +
> >> + /* Check for ranges property */
> >> + err = of_pci_range_parser_init(&parser, dev);
> >> + if (err)
> >> + return err;
> >> +
> >> + pr_debug("Parsing ranges property...\n");
> >> + for_each_of_pci_range(&parser, &range) {
> >> + /* Read next ranges element */
> >> + 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);
> >> +
> >> + /*
> >> + * If we failed translation or got a zero-sized region
> >> + * then skip this range
> >> + */
> >> + if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
> >> + continue;
> >> +
> >> + res = kzalloc(sizeof(struct resource), GFP_KERNEL);
> >> + if (!res) {
> >> + err = -ENOMEM;
> >> + goto bridge_ranges_nomem;
> >> + }
> >> +
> >> + of_pci_range_to_resource(&range, dev, res);
> >> +
> >> + if (resource_type(res) == IORESOURCE_IO)
> >> + *io_base = range.cpu_addr;
> >> +
> >> + pci_add_resource_offset(resources, res,
> >> + res->start - range.pci_addr);
> >> + }
> >> +
> >> + /* Apply architecture specific fixups for the ranges */
> >> + pcibios_fixup_bridge_ranges(resources);
> >> +
> >> + return 0;
> >> +
> >> +bridge_ranges_nomem:
> >> + pci_free_resource_list(resources);
> >> + return err;
> >> +}
> >> +
> >> +/**
> >> + * of_create_pci_host_bridge - Create a PCI host bridge structure using
> >> + * information passed in the DT.
> >> + * @parent: device owning this host bridge
> >> + * @ops: pci_ops associated with the host controller
> >> + * @host_data: opaque data structure used by the host controller.
> >> + *
> >> + * returns a pointer to the newly created pci_host_bridge structure, or
> >> + * NULL if the call failed.
> >> + *
> >> + * This function will try to obtain the host bridge domain number by
> >> + * using of_alias_get_id() call with "pci-domain" as a stem. If that
> >> + * fails, a local allocator will be used that will put each host bridge
> >> + * in a new domain.
> >> + */
> >> +struct pci_host_bridge *
> >> +of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops,
> >> void *host_data)
> >> +{
> >> + int err, domain, busno;
> >> + struct resource bus_range;
> >> + struct pci_bus *root_bus;
> >> + struct pci_host_bridge *bridge;
> >> + resource_size_t io_base;
> >> + LIST_HEAD(res);
> >> +
> >> + domain = of_alias_get_id(parent->of_node, "pci-domain");
> >> + if (domain == -ENODEV)
> >> + domain = domain_nr++;
> >> +
> >> + err = of_pci_parse_bus_range(parent->of_node, &bus_range);
> >> + if (err) {
> >> + dev_info(parent, "No bus range for %s, using default
> >> [0-255]\n",
> >> + parent->of_node->full_name);
> >> + bus_range.start = 0;
> >> + bus_range.end = 255;
> >> + bus_range.flags = IORESOURCE_BUS;
> >> + }
> >> + busno = bus_range.start;
> >> + pci_add_resource(&res, &bus_range);
> >> +
> >> + /* now parse the rest of host bridge bus ranges */
> >> + if (pci_host_bridge_of_get_ranges(parent->of_node, &res,
> >> &io_base))
> >> + return NULL;
> >> +
> >> + /* then create the root bus */
> >> + root_bus = pci_create_root_bus_in_domain(parent, domain, busno,
> >> + ops, host_data, &res);
> >> + if (!root_bus)
> >> + return NULL;
> >> +
> >> + bridge = to_pci_host_bridge(root_bus->bridge);
> >> + bridge->io_base = io_base;
> >> +
> >> + return bridge;
> >> +}
> >> +EXPORT_SYMBOL_GPL(of_create_pci_host_bridge);
> >> diff --git a/include/linux/pci.h b/include/linux/pci.h
> >> index 1eed009..0c5e269 100644
> >> --- a/include/linux/pci.h
> >> +++ b/include/linux/pci.h
> >> @@ -395,6 +395,7 @@ struct pci_host_bridge {
> >> struct device dev;
> >> struct pci_bus *bus; /* root bus */
> >> int domain_nr;
> >> + resource_size_t io_base; /* physical address for the start
> >> of I/O area */
> >> struct list_head windows; /* pci_host_bridge_windows */
> >> void (*release_fn)(struct pci_host_bridge *);
> >> void *release_data;
> >> @@ -1786,11 +1787,23 @@ static inline struct device_node
> >> *pci_bus_to_OF_node(struct pci_bus *bus)
> >> return bus ? bus->dev.of_node : NULL;
> >> }
> >>
> >> +struct pci_host_bridge *
> >> +of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops,
> >> + void *host_data);
> >> +
> >> +void pcibios_fixup_bridge_ranges(struct list_head *resources);
> >> #else /* CONFIG_OF */
> >> static inline void pci_set_of_node(struct pci_dev *dev) { }
> >> static inline void pci_release_of_node(struct pci_dev *dev) { }
> >> static inline void pci_set_bus_of_node(struct pci_bus *bus) { }
> >> static inline void pci_release_bus_of_node(struct pci_bus *bus) { }
> >> +
> >> +static inline struct pci_host_bridge *
> >> +pci_host_bridge_of_init(struct device *parent, struct pci_ops *ops,
> >> + void *host_data)
> >> +{
> >> + return NULL;
> >> +}
> >> #endif /* CONFIG_OF */
> >>
> >> #ifdef CONFIG_EEH
> >> --
> >> 1.9.0
> >>
> >>
> >> _______________________________________________
> >> linux-arm-kernel mailing list
> >> linux-arm-kernel@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
> >
> --
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> the body of a message to majordomo@vger.kernel.org
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>

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