linux/arch/x86/pci/acpi.c
Jon Mason b03e7495a8 PCI: Set PCI-E Max Payload Size on fabric
On a given PCI-E fabric, each device, bridge, and root port can have a
different PCI-E maximum payload size.  There is a sizable performance
boost for having the largest possible maximum payload size on each PCI-E
device.  However, if improperly configured, fatal bus errors can occur.
Thus, it is important to ensure that PCI-E payloads sends by a device
are never larger than the MPS setting of all devices on the way to the
destination.

This can be achieved two ways:

- A conservative approach is to use the smallest common denominator of
  the entire tree below a root complex for every device on that fabric.

This means for example that having a 128 bytes MPS USB controller on one
leg of a switch will dramatically reduce performances of a video card or
10GE adapter on another leg of that same switch.

It also means that any hierarchy supporting hotplug slots (including
expresscard or thunderbolt I suppose, dbl check that) will have to be
entirely clamped to 128 bytes since we cannot predict what will be
plugged into those slots, and we cannot change the MPS on a "live"
system.

- A more optimal way is possible, if it falls within a couple of
  constraints:
* The top-level host bridge will never generate packets larger than the
  smallest TLP (or if it can be controlled independently from its MPS at
  least)
* The device will never generate packets larger than MPS (which can be
  configured via MRRS)
* No support of direct PCI-E <-> PCI-E transfers between devices without
  some additional code to specifically deal with that case

Then we can use an approach that basically ignores downstream requests
and focuses exclusively on upstream requests. In that case, all we need
to care about is that a device MPS is no larger than its parent MPS,
which allows us to keep all switches/bridges to the max MPS supported by
their parent and eventually the PHB.

In this case, your USB controller would no longer "starve" your 10GE
Ethernet and your hotplug slots won't affect your global MPS.
Additionally, the hotplugged devices themselves can be configured to a
larger MPS up to the value configured in the hotplug bridge.

To choose between the two available options, two PCI kernel boot args
have been added to the PCI calls.  "pcie_bus_safe" will provide the
former behavior, while "pcie_bus_perf" will perform the latter behavior.
By default, the latter behavior is used.

NOTE: due to the location of the enablement, each arch will need to add
calls to this function.  This patch only enables x86.

This patch includes a number of changes recommended by Benjamin
Herrenschmidt.

Tested-by: Jordan_Hargrave@dell.com
Signed-off-by: Jon Mason <mason@myri.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-08-01 11:49:16 -07:00

414 lines
10 KiB
C

#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/dmi.h>
#include <linux/slab.h>
#include <asm/numa.h>
#include <asm/pci_x86.h>
struct pci_root_info {
struct acpi_device *bridge;
char *name;
unsigned int res_num;
struct resource *res;
struct pci_bus *bus;
int busnum;
};
static bool pci_use_crs = true;
static int __init set_use_crs(const struct dmi_system_id *id)
{
pci_use_crs = true;
return 0;
}
static const struct dmi_system_id pci_use_crs_table[] __initconst = {
/* http://bugzilla.kernel.org/show_bug.cgi?id=14183 */
{
.callback = set_use_crs,
.ident = "IBM System x3800",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
DMI_MATCH(DMI_PRODUCT_NAME, "x3800"),
},
},
/* https://bugzilla.kernel.org/show_bug.cgi?id=16007 */
/* 2006 AMD HT/VIA system with two host bridges */
{
.callback = set_use_crs,
.ident = "ASRock ALiveSATA2-GLAN",
.matches = {
DMI_MATCH(DMI_PRODUCT_NAME, "ALiveSATA2-GLAN"),
},
},
{}
};
void __init pci_acpi_crs_quirks(void)
{
int year;
if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year < 2008)
pci_use_crs = false;
dmi_check_system(pci_use_crs_table);
/*
* If the user specifies "pci=use_crs" or "pci=nocrs" explicitly, that
* takes precedence over anything we figured out above.
*/
if (pci_probe & PCI_ROOT_NO_CRS)
pci_use_crs = false;
else if (pci_probe & PCI_USE__CRS)
pci_use_crs = true;
printk(KERN_INFO "PCI: %s host bridge windows from ACPI; "
"if necessary, use \"pci=%s\" and report a bug\n",
pci_use_crs ? "Using" : "Ignoring",
pci_use_crs ? "nocrs" : "use_crs");
}
static acpi_status
resource_to_addr(struct acpi_resource *resource,
struct acpi_resource_address64 *addr)
{
acpi_status status;
struct acpi_resource_memory24 *memory24;
struct acpi_resource_memory32 *memory32;
struct acpi_resource_fixed_memory32 *fixed_memory32;
memset(addr, 0, sizeof(*addr));
switch (resource->type) {
case ACPI_RESOURCE_TYPE_MEMORY24:
memory24 = &resource->data.memory24;
addr->resource_type = ACPI_MEMORY_RANGE;
addr->minimum = memory24->minimum;
addr->address_length = memory24->address_length;
addr->maximum = addr->minimum + addr->address_length - 1;
return AE_OK;
case ACPI_RESOURCE_TYPE_MEMORY32:
memory32 = &resource->data.memory32;
addr->resource_type = ACPI_MEMORY_RANGE;
addr->minimum = memory32->minimum;
addr->address_length = memory32->address_length;
addr->maximum = addr->minimum + addr->address_length - 1;
return AE_OK;
case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
fixed_memory32 = &resource->data.fixed_memory32;
addr->resource_type = ACPI_MEMORY_RANGE;
addr->minimum = fixed_memory32->address;
addr->address_length = fixed_memory32->address_length;
addr->maximum = addr->minimum + addr->address_length - 1;
return AE_OK;
case ACPI_RESOURCE_TYPE_ADDRESS16:
case ACPI_RESOURCE_TYPE_ADDRESS32:
case ACPI_RESOURCE_TYPE_ADDRESS64:
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 > 0) {
return AE_OK;
}
break;
}
return AE_ERROR;
}
static acpi_status
count_resource(struct acpi_resource *acpi_res, void *data)
{
struct pci_root_info *info = data;
struct acpi_resource_address64 addr;
acpi_status status;
status = resource_to_addr(acpi_res, &addr);
if (ACPI_SUCCESS(status))
info->res_num++;
return AE_OK;
}
static acpi_status
setup_resource(struct acpi_resource *acpi_res, void *data)
{
struct pci_root_info *info = data;
struct resource *res;
struct acpi_resource_address64 addr;
acpi_status status;
unsigned long flags;
u64 start, end;
status = resource_to_addr(acpi_res, &addr);
if (!ACPI_SUCCESS(status))
return AE_OK;
if (addr.resource_type == ACPI_MEMORY_RANGE) {
flags = IORESOURCE_MEM;
if (addr.info.mem.caching == ACPI_PREFETCHABLE_MEMORY)
flags |= IORESOURCE_PREFETCH;
} else if (addr.resource_type == ACPI_IO_RANGE) {
flags = IORESOURCE_IO;
} else
return AE_OK;
start = addr.minimum + addr.translation_offset;
end = addr.maximum + addr.translation_offset;
res = &info->res[info->res_num];
res->name = info->name;
res->flags = flags;
res->start = start;
res->end = end;
res->child = NULL;
if (!pci_use_crs) {
dev_printk(KERN_DEBUG, &info->bridge->dev,
"host bridge window %pR (ignored)\n", res);
return AE_OK;
}
info->res_num++;
if (addr.translation_offset)
dev_info(&info->bridge->dev, "host bridge window %pR "
"(PCI address [%#llx-%#llx])\n",
res, res->start - addr.translation_offset,
res->end - addr.translation_offset);
else
dev_info(&info->bridge->dev, "host bridge window %pR\n", res);
return AE_OK;
}
static bool resource_contains(struct resource *res, resource_size_t point)
{
if (res->start <= point && point <= res->end)
return true;
return false;
}
static void coalesce_windows(struct pci_root_info *info, unsigned long type)
{
int i, j;
struct resource *res1, *res2;
for (i = 0; i < info->res_num; i++) {
res1 = &info->res[i];
if (!(res1->flags & type))
continue;
for (j = i + 1; j < info->res_num; j++) {
res2 = &info->res[j];
if (!(res2->flags & type))
continue;
/*
* I don't like throwing away windows because then
* our resources no longer match the ACPI _CRS, but
* the kernel resource tree doesn't allow overlaps.
*/
if (resource_contains(res1, res2->start) ||
resource_contains(res1, res2->end) ||
resource_contains(res2, res1->start) ||
resource_contains(res2, res1->end)) {
res1->start = min(res1->start, res2->start);
res1->end = max(res1->end, res2->end);
dev_info(&info->bridge->dev,
"host bridge window expanded to %pR; %pR ignored\n",
res1, res2);
res2->flags = 0;
}
}
}
}
static void add_resources(struct pci_root_info *info)
{
int i;
struct resource *res, *root, *conflict;
if (!pci_use_crs)
return;
coalesce_windows(info, IORESOURCE_MEM);
coalesce_windows(info, IORESOURCE_IO);
for (i = 0; i < info->res_num; i++) {
res = &info->res[i];
if (res->flags & IORESOURCE_MEM)
root = &iomem_resource;
else if (res->flags & IORESOURCE_IO)
root = &ioport_resource;
else
continue;
conflict = insert_resource_conflict(root, res);
if (conflict)
dev_info(&info->bridge->dev,
"ignoring host bridge window %pR (conflicts with %s %pR)\n",
res, conflict->name, conflict);
else
pci_bus_add_resource(info->bus, res, 0);
}
}
static void
get_current_resources(struct acpi_device *device, int busnum,
int domain, struct pci_bus *bus)
{
struct pci_root_info info;
size_t size;
if (pci_use_crs)
pci_bus_remove_resources(bus);
info.bridge = device;
info.bus = bus;
info.res_num = 0;
acpi_walk_resources(device->handle, METHOD_NAME__CRS, count_resource,
&info);
if (!info.res_num)
return;
size = sizeof(*info.res) * info.res_num;
info.res = kmalloc(size, GFP_KERNEL);
if (!info.res)
goto res_alloc_fail;
info.name = kasprintf(GFP_KERNEL, "PCI Bus %04x:%02x", domain, busnum);
if (!info.name)
goto name_alloc_fail;
info.res_num = 0;
acpi_walk_resources(device->handle, METHOD_NAME__CRS, setup_resource,
&info);
add_resources(&info);
return;
name_alloc_fail:
kfree(info.res);
res_alloc_fail:
return;
}
struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
{
struct acpi_device *device = root->device;
int domain = root->segment;
int busnum = root->secondary.start;
struct pci_bus *bus;
struct pci_sysdata *sd;
int node;
#ifdef CONFIG_ACPI_NUMA
int pxm;
#endif
if (domain && !pci_domains_supported) {
printk(KERN_WARNING "pci_bus %04x:%02x: "
"ignored (multiple domains not supported)\n",
domain, busnum);
return NULL;
}
node = -1;
#ifdef CONFIG_ACPI_NUMA
pxm = acpi_get_pxm(device->handle);
if (pxm >= 0)
node = pxm_to_node(pxm);
if (node != -1)
set_mp_bus_to_node(busnum, node);
else
#endif
node = get_mp_bus_to_node(busnum);
if (node != -1 && !node_online(node))
node = -1;
/* Allocate per-root-bus (not per bus) arch-specific data.
* TODO: leak; this memory is never freed.
* It's arguable whether it's worth the trouble to care.
*/
sd = kzalloc(sizeof(*sd), GFP_KERNEL);
if (!sd) {
printk(KERN_WARNING "pci_bus %04x:%02x: "
"ignored (out of memory)\n", domain, busnum);
return NULL;
}
sd->domain = domain;
sd->node = node;
/*
* Maybe the desired pci bus has been already scanned. In such case
* it is unnecessary to scan the pci bus with the given domain,busnum.
*/
bus = pci_find_bus(domain, busnum);
if (bus) {
/*
* If the desired bus exits, the content of bus->sysdata will
* be replaced by sd.
*/
memcpy(bus->sysdata, sd, sizeof(*sd));
kfree(sd);
} else {
bus = pci_create_bus(NULL, busnum, &pci_root_ops, sd);
if (bus) {
get_current_resources(device, busnum, domain, bus);
bus->subordinate = pci_scan_child_bus(bus);
}
}
/* After the PCI-E bus has been walked and all devices discovered,
* configure any settings of the fabric that might be necessary.
*/
if (bus) {
struct pci_bus *child;
list_for_each_entry(child, &bus->children, node)
pcie_bus_configure_settings(child, child->self->pcie_mpss);
}
if (!bus)
kfree(sd);
if (bus && node != -1) {
#ifdef CONFIG_ACPI_NUMA
if (pxm >= 0)
dev_printk(KERN_DEBUG, &bus->dev,
"on NUMA node %d (pxm %d)\n", node, pxm);
#else
dev_printk(KERN_DEBUG, &bus->dev, "on NUMA node %d\n", node);
#endif
}
return bus;
}
int __init pci_acpi_init(void)
{
struct pci_dev *dev = NULL;
if (acpi_noirq)
return -ENODEV;
printk(KERN_INFO "PCI: Using ACPI for IRQ routing\n");
acpi_irq_penalty_init();
pcibios_enable_irq = acpi_pci_irq_enable;
pcibios_disable_irq = acpi_pci_irq_disable;
x86_init.pci.init_irq = x86_init_noop;
if (pci_routeirq) {
/*
* PCI IRQ routing is set up by pci_enable_device(), but we
* also do it here in case there are still broken drivers that
* don't use pci_enable_device().
*/
printk(KERN_INFO "PCI: Routing PCI interrupts for all devices because \"pci=routeirq\" specified\n");
for_each_pci_dev(dev)
acpi_pci_irq_enable(dev);
}
return 0;
}