In the static enumeration profile, the user may override the memory
space associated with a bus. This is needed so that when a PCI endpoint
is later discovered, it can fit within its upstream bus's memory space
without requiring that the bus's memory be resized (and hence other
device potentially moved).
Signed-off-by: Jason Tang <jason.tang2@xxxxxxx>
---
Documentation/kernel-parameters.txt | 2 ++
drivers/pci/pci.h | 2 ++
drivers/pci/pci_static_enum.c | 47 +++++++++++++++++++++++++++++++++++
drivers/pci/probe.c | 3 +++
4 files changed, 54 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index af2ce92..5413155 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2773,6 +2773,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
and <option> is any combination of:
B<secondary>-<subordinate> -
force secondary and subordinate bus numbers
+ M<address>-<address> -
+ set MMIO memory range
All values are in hexadecimal.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 665c798..db710ac 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -327,6 +327,7 @@ int pci_static_enum_exists(void);
void pci_static_enum_bus_nums(struct pci_bus *bus);
int pci_static_enum_get_busnr(struct pci_bus *bus, struct pci_dev *dev,
int default_busnr);
+void pci_static_enum_device(struct pci_dev *dev);
/**
* pci_bus_subordinate() - return the subordinate bus number assigned
* to @dev by the static enumeration profile, or 0 if not set
@@ -344,6 +345,7 @@ static inline int pci_static_enum_get_busnr(struct pci_bus *bus, struct pci_dev
{
return default_busnr;
}
+static inline void pci_static_enum_device(struct pci_dev *dev) { return; }
static inline unsigned char pci_bus_subordinate(struct pci_bus *bus)
{
return 0;
diff --git a/drivers/pci/pci_static_enum.c b/drivers/pci/pci_static_enum.c
index dbdc973..9c9ea4a 100644
--- a/drivers/pci/pci_static_enum.c
+++ b/drivers/pci/pci_static_enum.c
@@ -28,6 +28,7 @@ struct pci_static_enum_setting {
int devfn;
unsigned char secondary_bus;
unsigned char subordinate_bus;
+ resource_size_t bridgemem_start, bridgemem_end;
};
LIST_HEAD(settings_list);
@@ -82,6 +83,7 @@ static int pci_static_enum_parse_options(void)
struct pci_static_enum_setting *setting, *tmp;
int seg, bus, slot, func;
unsigned int secondary_bus, subordinate_bus;
+ resource_size_t start, end;
int count = 0, entry_found = 0;
if (strncmp(p, "off", 3) == 0) {
@@ -133,6 +135,12 @@ static int pci_static_enum_parse_options(void)
p += count;
setting->secondary_bus = secondary_bus;
setting->subordinate_bus = subordinate_bus;
+ } else
+ if (sscanf(p, "M%llx-%llx%n", &start, &end, &count)
+ == 2 && count > 0) {
+ p += count;
+ setting->bridgemem_start = start;
+ setting->bridgemem_end = end;
} else {
pr_err(PREFIX "Invalid enum option: `%s'\n", p);
return -1;
@@ -249,3 +257,42 @@ int pci_static_enum_get_busnr(struct pci_bus *bus, struct pci_dev *dev,
return setting->secondary_bus;
return default_num;
}
+
+/**
+ * pci_static_enum_set_bridge_memory() - override a PCI bridge's
+ * memory base and limit registers, according to its static
+ * enumeration profile
+ * @dev: PCI bridge device to override
+ * @setting: device's static enumeration profile
+ */
+static void pci_static_enum_set_bridge_memory(struct pci_dev *dev, struct pci_static_enum_setting
+ *setting)
+{
+ u16 mem_base_lo, mem_limit_lo;
+
+ dev_info(&dev->dev, "Overriding memory base and limit to %pa-%pa\n",
+ &setting->bridgemem_start, &setting->bridgemem_end);
+ mem_base_lo = setting->bridgemem_start >> 16;
+ mem_limit_lo = (setting->bridgemem_end >> 16) & ~0xf;
+ pci_write_config_word(dev, PCI_MEMORY_BASE, mem_base_lo);
+ pci_write_config_word(dev, PCI_MEMORY_LIMIT, mem_limit_lo);
+}
+
+/**
+ * pci_static_enum_device() - override a device's memory
+ * configuration, according to its static enumeration profile
+ * @dev: PCI device to override
+ */
+void pci_static_enum_device(struct pci_dev *dev)
+{
+ struct pci_static_enum_setting *setting;
+
+ /* if dev is a bridge, set its memory regions */
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ setting = pci_static_enum_find_setting(pci_domain_nr(dev->bus),
+ dev->bus->number,
+ dev->devfn);
+ if (setting && setting->bridgemem_start)
+ pci_static_enum_set_bridge_memory(dev, setting);
+ }
+}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b3e7db4..418fb59 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -315,6 +315,9 @@ static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
{
unsigned int pos, reg;
+ /* Override any memory settings that BIOS may have assigned */
+ pci_static_enum_device(dev);
+
for (pos = 0; pos < howmany; pos++) {
struct resource *res = &dev->resource[pos];
reg = PCI_BASE_ADDRESS_0 + (pos << 2);
--
1.7.9.5
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