Re: [Linaro-acpi] [RFC PATCH 4/4] arm64, acpi, pci: Provide arch-specific calls for PCI host bridge dirver (PNP0A03).

On Fri, Nov 07, 2014 at 01:27:56PM +0000, Tomasz Nowicki wrote:

Code inspired by arch/x86/pci/acpi.c and arch/ia64/pci/pci.c files. The main reasons why we need this:

• parse and manage resources (BUS, IO and MEM)
• create pci root bus and enumerate its children
• provide PCI config space accessors (via MMCONFIG)

Hi Tomasz,

I have some comments to your code:

Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org

arch/arm64/include/asm/pci.h | 8 + arch/arm64/kernel/pci.c | 401 +++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 391 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h index fded096..ecd940f 100644 --- a/arch/arm64/include/asm/pci.h +++ b/arch/arm64/include/asm/pci.h @@ -33,6 +33,14 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel) extern int isa_dma_bridge_buggy;

#ifdef CONFIG_PCI +struct pci_controller {

•   struct acpi_device *companion;
  

•   int segment;
  

•   int node;               /* nearest node with memory or NUMA_NO_NODE for global allocation */
  

+};

+#define PCI_CONTROLLER(busdev) ((struct pci_controller *) busdev->sysdata)

I am trying to move away from the model where the architecture dictates the shape of the pci_controller structure. Can I suggest that you put all this code and the one under #ifdef CONFIG_ACPI in a separate file, say arch/arm64/kernel/pci-acpi.c ? Or that you add an #ifdef CONFIG_ACPI around this structure definition?

I can't see anyone using this definition outside ACPI (due to struct acpi_device dependency) and I would like to avoid it conflicting with other host bridge drivers trying to define the same name structure.

static inline int pci_proc_domain(struct pci_bus *bus) { return 1; diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 42fb195..cc34ded 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -1,6 +1,10 @@ /*

• • Code borrowed from powerpc/kernel/pci-common.c

• • Code borrowed from powerpc/kernel/pci-common.c and arch/ia64/pci/pci.c
• • Copyright (c) 2002, 2005 Hewlett-Packard Development Company, L.P.

• • David Mosberger-Tang <davidm@hpl.hp.com>
    

• • Bjorn Helgaas <bjorn.helgaas@hp.com>
    

• • Copyright (C) 2004 Silicon Graphics, Inc.
  • Copyright (C) 2003 Anton Blanchard anton@au.ibm.com, IBM
  • Copyright (C) 2014 ARM Ltd.

@@ -17,10 +21,16 @@ #include <linux/mm.h> #include <linux/of_pci.h> #include <linux/of_platform.h> +#include <linux/of_address.h> #include <linux/slab.h> +#include <linux/pci.h> +#include <linux/acpi.h> +#include <linux/mmconfig.h>

#include <asm/pci-bridge.h>

+#define PREFIX "PCI: "

Where is this used?

/*

• Called after each bus is probed, but before its children are examined

*/ @@ -43,7 +53,8 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res, */ int pcibios_add_device(struct pci_dev *dev) {

•   dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
  

•   if (acpi_disabled)
  

•           dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
  
    return 0;
  

} @@ -54,45 +65,399 @@ static bool dt_domain_found = false;

void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) {

•   int domain = of_get_pci_domain_nr(parent->of_node);
  

•   int domain = -1;
  
  

•   if (domain >= 0) {
  

•           dt_domain_found = true;
  

•   } else if (dt_domain_found == true) {
  

•           dev_err(parent, "Node %s is missing \"linux,pci-domain\" property in DT\n",
  

•                   parent->of_node->full_name);
  

•           return;
  

•   if (acpi_disabled) {
  

•           domain = of_get_pci_domain_nr(parent->of_node);
  

•           if (domain >= 0) {
  

•                   dt_domain_found = true;
  

•           } else if (dt_domain_found == true) {
  

•                   dev_err(parent, "Node %s is missing \"linux,pci-domain\" property in DT\n",
  

•                           parent->of_node->full_name);
  

•                   return;
  

•           } else {
  

•                   domain = pci_get_new_domain_nr();
  

•           }
    } else {
  

•           domain = pci_get_new_domain_nr();
  

•           /*
  

•            * Take the domain nr from associated private data.
  

•            * Case where bus has parent is covered in pci_alloc_bus()
  

•            */
  

•           if (!parent)
  

•                   domain = PCI_CONTROLLER(bus)->segment;
  

I would also like to wrap this into an ACPI specific function. Reason for it is that when I get to split the pci_host_bridge creation out of pci_create_root_bus() this will become a pci_controller property.

    }

    bus->domain_nr = domain;

} #endif

+static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus,

•                             unsigned int devfn)
  

+{

•   struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
  

•   if (cfg && cfg->virt)
  

•           return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
  

•   return NULL;
  

+}

/*

• raw_pci_read/write - Platform-specific PCI config space access.

• • Default empty implementation. Replace with an architecture-specific setup
• • routine, if necessary.
  */

int raw_pci_read(unsigned int domain, unsigned int bus, unsigned int devfn, int reg, int len, u32 *val) {

•   return -EINVAL;
  

•   char __iomem *addr;
  

•   if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  

+err: *val = -1;

I believe the general usage is to have labels on their own line.

•           return -EINVAL;
  

•   }
  

•   rcu_read_lock();
  

•   addr = pci_dev_base(domain, bus, devfn);
  

•   if (!addr) {
  

•           rcu_read_unlock();
  

•           goto err;
  

•   }
  

•   switch (len) {
  

•   case 1:
  

•           *val = readb(addr + reg);
  

•           break;
  

•   case 2:
  

•           *val = readw(addr + reg);
  

•           break;
  

•   case 4:
  

•           *val = readl(addr + reg);
  

•           break;
  

•   }
  

•   rcu_read_unlock();
  

•   return 0;
  

}

int raw_pci_write(unsigned int domain, unsigned int bus, unsigned int devfn, int reg, int len, u32 val) {

•   return -EINVAL;
  

•   char __iomem *addr;
  

•   if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  

•           return -EINVAL;
  

•   rcu_read_lock();
  

•   addr = pci_dev_base(domain, bus, devfn);
  

•   if (!addr) {
  

•           rcu_read_unlock();
  

•           return -EINVAL;
  

•   }
  

•   switch (len) {
  

•   case 1:
  

•           writeb(val, addr + reg);
  

•           break;
  

•   case 2:
  

•           writew(val, addr + reg);
  

•           break;
  

•   case 4:
  

•           writel(val, addr + reg);
  

•           break;
  

•   }
  

•   rcu_read_unlock();
  

•   return 0;
  

}

These raw_pci_{read,write} functions are all ACPI specific so they can move into the new file as well.

#ifdef CONFIG_ACPI +static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,

•               int size, u32 *value)
  

+{

•   return raw_pci_read(pci_domain_nr(bus), bus->number,
  

•                       devfn, where, size, value);
  

+}

+static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,

•                int size, u32 value)
  

+{

•   return raw_pci_write(pci_domain_nr(bus), bus->number,
  

•                        devfn, where, size, value);
  

+}

+struct pci_ops pci_root_ops = {

•   .read = pci_read,
  

•   .write = pci_write,
  

+};

+static struct pci_controller *alloc_pci_controller(int seg) +{

•   struct pci_controller *controller;
  

•   controller = kzalloc(sizeof(*controller), GFP_KERNEL);
  

•   if (!controller)
  

•           return NULL;
  

•   controller->segment = seg;
  

•   return controller;
  

+}

+struct pci_root_info {

•   struct acpi_device *bridge;
  

•   struct pci_controller *controller;
  

•   struct list_head resources;
  

•   struct resource *res;
  

•   resource_size_t *res_offset;
  

Why do you need to keep an array of res_offsets here? You only seem to be using the values once when you add the resource to the host bridge windows.

•   unsigned int res_num;
  

•   char *name;
  

+};

+static acpi_status resource_to_window(struct acpi_resource *resource,

•                                 struct acpi_resource_address64 *addr)
  

+{

•   acpi_status status;
  

•   /*
  

•    * We're only interested in _CRS descriptors that are
  

•    *      - address space descriptors for memory
  

•    *      - non-zero size
  

•    *      - producers, i.e., the address space is routed downstream,
  

•    *        not consumed by the bridge itself
  

•    */
  

•   status = acpi_resource_to_address64(resource, addr);
  

•   if (ACPI_SUCCESS(status) &&
  

•       (addr->resource_type == ACPI_MEMORY_RANGE ||
  

•        addr->resource_type == ACPI_IO_RANGE) &&
  

•       addr->address_length &&
  

•       addr->producer_consumer == ACPI_PRODUCER)
  

•           return AE_OK;
  

•   return AE_ERROR;
  

+}

+static acpi_status count_window(struct acpi_resource *resource, void *data) +{

•   unsigned int *windows = (unsigned int *) data;
  

•   struct acpi_resource_address64 addr;
  

•   acpi_status status;
  

•   status = resource_to_window(resource, &addr);
  

•   if (ACPI_SUCCESS(status))
  

•           (*windows)++;
  

•   return AE_OK;
  

+}

+static acpi_status add_window(struct acpi_resource *res, void *data) +{

•   struct pci_root_info *info = data;
  

•   struct resource *resource;
  

•   struct acpi_resource_address64 addr;
  

•   acpi_status status;
  

•   unsigned long flags;
  

•   struct resource *root;
  

•   u64 start;
  

•   /* Return AE_OK for non-window resources to keep scanning for more */
  

•   status = resource_to_window(res, &addr);
  

•   if (!ACPI_SUCCESS(status))
  

•           return AE_OK;
  

•   if (addr.resource_type == ACPI_MEMORY_RANGE) {
  

•           flags = IORESOURCE_MEM;
  

•           root = &iomem_resource;
  

•   } else if (addr.resource_type == ACPI_IO_RANGE) {
  

•           flags = IORESOURCE_IO;
  

•           root = &ioport_resource;
  

•   } else
  

•           return AE_OK;
  

•   start = addr.minimum + addr.translation_offset;
  

•   resource = &info->res[info->res_num];
  

•   resource->name = info->name;
  

•   resource->flags = flags;
  

•   resource->start = start;
  

•   resource->end = resource->start + addr.address_length - 1;
  

•   if (flags & IORESOURCE_IO) {
  

•           unsigned long port;
  

•           int err;
  

•           err = pci_register_io_range(start, addr.address_length);
  

•           if (err)
  

•                   return AE_OK;
  

•           port = pci_address_to_pio(start);
  

•           if (port == (unsigned long)-1)
  

•                   return AE_OK;
  

•           resource->start = port;
  

•           resource->end = port + addr.address_length - 1;
  

•           if (pci_remap_iospace(resource, start) < 0)
  

•                   return AE_OK;
  

You seem to leave around invalid resources every time you return in this code path due to your choice of ignoring error conditions.

I think there are a few things that can be streamlined in this patch, but overall I think it looks promising.

Best regards, Liviu

•           info->res_offset[info->res_num] = 0;
  

•   } else
  

•           info->res_offset[info->res_num] = addr.translation_offset;
  

•   if (insert_resource(root, resource)) {
  

•           dev_err(&info->bridge->dev,
  

•                   "can't allocate host bridge window %pR\n",
  

•                   resource);
  

•   } else {
  

•           if (addr.translation_offset)
  

•                   dev_info(&info->bridge->dev, "host bridge window %pR "
  

•                            "(PCI address [%#llx-%#llx])\n",
  

•                            resource,
  

•                            resource->start - addr.translation_offset,
  

•                            resource->end - addr.translation_offset);
  

•           else
  

•                   dev_info(&info->bridge->dev,
  

•                            "host bridge window %pR\n", resource);
  

•   }
  

•   pci_add_resource_offset(&info->resources, resource,
  

•                           info->res_offset[info->res_num]);
  

•   info->res_num++;
  

•   return AE_OK;
  

+}

+static void free_pci_root_info_res(struct pci_root_info *info) +{

•   kfree(info->name);
  

•   kfree(info->res);
  

•   info->res = NULL;
  

•   kfree(info->res_offset);
  

•   info->res_offset = NULL;
  

•   info->res_num = 0;
  

•   kfree(info->controller);
  

•   info->controller = NULL;
  

+}

+static void __release_pci_root_info(struct pci_root_info *info) +{

•   int i;
  

•   struct resource *res;
  

•   for (i = 0; i < info->res_num; i++) {
  

•           res = &info->res[i];
  

•           if (!res->parent)
  

•                   continue;
  

•           if (!(res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
  

•                   continue;
  

•           release_resource(res);
  

•   }
  

•   free_pci_root_info_res(info);
  

•   kfree(info);
  

+}

+static void release_pci_root_info(struct pci_host_bridge *bridge) +{

•   struct pci_root_info *info = bridge->release_data;
  

•   __release_pci_root_info(info);
  

+}

+static int +probe_pci_root_info(struct pci_root_info *info, struct acpi_device *device,

•           int busnum, int domain)
  

+{

•   char *name;
  

•   name = kmalloc(16, GFP_KERNEL);
  

•   if (!name)
  

•           return -ENOMEM;
  

•   sprintf(name, "PCI Bus %04x:%02x", domain, busnum);
  

•   info->bridge = device;
  

•   info->name = name;
  

•   acpi_walk_resources(device->handle, METHOD_NAME__CRS, count_window,
  

•                   &info->res_num);
  

•   if (info->res_num) {
  

•           info->res =
  

•                   kzalloc_node(sizeof(*info->res) * info->res_num,
  

•                                GFP_KERNEL, info->controller->node);
  

•           if (!info->res) {
  

•                   kfree(name);
  

•                   return -ENOMEM;
  

•           }
  

•           info->res_offset =
  

•                   kzalloc_node(sizeof(*info->res_offset) * info->res_num,
  

•                                   GFP_KERNEL, info->controller->node);
  

•           if (!info->res_offset) {
  

•                   kfree(name);
  

•                   kfree(info->res);
  

•                   info->res = NULL;
  

•                   return -ENOMEM;
  

•           }
  

•           info->res_num = 0;
  

•           acpi_walk_resources(device->handle, METHOD_NAME__CRS,
  

•                   add_window, info);
  

•   } else
  

•           kfree(name);
  

•   return 0;
  

+}

/* Root bridge scanning */ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) {

•   /* TODO: Should be revisited when implementing PCI on ACPI */
  

•   return NULL;
  

•   struct acpi_device *device = root->device;
  

•   int domain = root->segment;
  

•   int bus = root->secondary.start;
  

•   struct pci_controller *controller;
  

•   struct pci_root_info *info = NULL;
  

•   int busnum = root->secondary.start;
  

•   struct pci_bus *pbus;
  

•   int ret;
  

•   controller = alloc_pci_controller(domain);
  

•   if (!controller)
  

•           return NULL;
  

•   controller->companion = device;
  

•   controller->node = acpi_get_node(device->handle);
  

•   info = kzalloc(sizeof(*info), GFP_KERNEL);
  

•   if (!info) {
  

•           dev_err(&device->dev,
  

•                           "pci_bus %04x:%02x: ignored (out of memory)\n",
  

•                           domain, busnum);
  

•           kfree(controller);
  

•           return NULL;
  

•   }
  

•   info->controller = controller;
  

•   INIT_LIST_HEAD(&info->resources);
  

•   ret = probe_pci_root_info(info, device, busnum, domain);
  

•   if (ret) {
  

•           kfree(info->controller);
  

•           kfree(info);
  

•           return NULL;
  

•   }
  

•   /* insert busn resource at first */
  

•   pci_add_resource(&info->resources, &root->secondary);
  

•   pbus = pci_create_root_bus(NULL, bus, &pci_root_ops, controller,
  

•                              &info->resources);
  

•   if (!pbus) {
  

•           pci_free_resource_list(&info->resources);
  

•           __release_pci_root_info(info);
  

•           return NULL;
  

•   }
  

•   pci_set_host_bridge_release(to_pci_host_bridge(pbus->bridge),
  

•                   release_pci_root_info, info);
  

•   pci_scan_child_bus(pbus);
  

•   return pbus;
  

} -#endif

+#endif /* CONFIG_ACPI */

1.9.1