If the upstream bridge has a static enumeration profile, then reassign
all of the device's MMIO BARs to fit within the upstream bridge's
memory space. Use a first-fit algorithm to minimize memory holes.
Signed-off-by: Jason Tang <jason.tang2@xxxxxxx>
---
drivers/pci/pci_static_enum.c | 175 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 175 insertions(+)
diff --git a/drivers/pci/pci_static_enum.c b/drivers/pci/pci_static_enum.c
index f000c7f..50f4db4 100644
--- a/drivers/pci/pci_static_enum.c
+++ b/drivers/pci/pci_static_enum.c
@@ -21,6 +21,12 @@
static DEFINE_SPINLOCK(static_enum_lock);
+struct pci_static_enum_memspace {
+ struct list_head list;
+ resource_size_t start;
+ resource_size_t size;
+};
+
struct pci_static_enum_setting {
struct list_head list;
int seg;
@@ -29,6 +35,7 @@ struct pci_static_enum_setting {
unsigned char secondary_bus;
unsigned char subordinate_bus;
resource_size_t bridgemem_start, bridgemem_end;
+ struct list_head memspace;
};
LIST_HEAD(settings_list);
@@ -124,6 +131,7 @@ static int pci_static_enum_parse_options(void)
setting->seg = seg;
setting->bus = bus;
setting->devfn = PCI_DEVFN(slot, func);
+ INIT_LIST_HEAD(&setting->memspace);
list_add(&setting->list, &settings_list);
}
@@ -138,9 +146,18 @@ static int pci_static_enum_parse_options(void)
} else
if (sscanf(p, "M%llx-%llx%n", &start, &end, &count)
== 2 && count > 0) {
+ struct pci_static_enum_memspace *mem;
p += count;
setting->bridgemem_start = start;
setting->bridgemem_end = end;
+ mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+ if (!mem) {
+ pr_err(PREFIX "Out of memory\n");
+ return -1;
+ }
+ mem->start = start;
+ mem->size = end - start + 1;
+ list_add_tail(&mem->list, &setting->memspace);
} else {
pr_err(PREFIX "Invalid enum option: `%s'\n", p);
return -1;
@@ -358,6 +375,149 @@ static void pci_static_enum_set_bridge_memory(struct pci_dev *dev, struct pci_st
}
/**
+ * pci_static_enum_assign_space() - search for aligned memory
+ * @setting: device's static enumeration profile
+ * @requested_size: number of bytes requested by a BAR
+ *
+ * Use a first-fit algorithm to find a memory that is properly
+ * aligned. Reserve that memory for a BAR, and then update the free
+ * space list.
+ *
+ * Return: starting 32-bit address for memory, or 0 if insufficient
+ * space.
+ */
+static u32 pci_static_enum_assign_space(struct pci_static_enum_setting *setting,
+ u32 requested_size)
+{
+ struct pci_static_enum_memspace *mem;
+ int found_space = 0;
+ resource_size_t start_addr;
+
+ list_for_each_entry(mem, &setting->memspace, list) {
+ /* make sure that free space is aligned */
+ start_addr = ALIGN(mem->start, requested_size);
+ if (start_addr + requested_size < mem->start + mem->size) {
+ found_space = 1;
+ break;
+ }
+ }
+
+ if (!found_space)
+ return 0;
+
+ /* update the free space list */
+ if (start_addr == mem->start && requested_size == mem->size) {
+ /* delete block */
+ list_del(&mem->list);
+ kfree(mem);
+ } else if (start_addr == mem->start) {
+ /* trim from start */
+ mem->start += requested_size;
+ mem->size -= requested_size;
+ } else if (start_addr + requested_size == mem->start + mem->size) {
+ /* trim from end */
+ mem->size -= requested_size;
+ } else {
+ /* split block */
+ struct pci_static_enum_memspace *mem2;
+
+ mem2 = kmalloc(sizeof(*mem), GFP_KERNEL);
+ mem2->start = start_addr + requested_size;
+ mem2->size = start_addr + mem->size - mem2->start;
+ mem->size = mem2->start - mem->start;
+ list_add(&mem2->list, &mem->list);
+ }
+ return (u32) start_addr;
+}
+
+#define PCI_COMMAND_DECODE_ENABLE (PCI_COMMAND_MEMORY | PCI_COMMAND_IO)
+
+/**
+ * pci_static_enum_reset_mmio_bar() - scan a particular BAR on a PCI
+ * device, reassigning the BAR if it is for a MMIO memory space
+ * @dev: PCI device to override
+ * @setting: static enumeration profile of the device's upstream bus
+ * @reg: offset into dev's configuration space, from which to read BAR
+ * value
+ */
+static void pci_static_enum_reset_mmio_bar(struct pci_dev *dev, struct pci_static_enum_setting
+ *setting, unsigned int reg)
+{
+ u32 orig_bar, sz;
+ u32 requested_size = 0;
+ u32 assigned_addr = 0;
+ u16 orig_cmd;
+
+ if (!dev->mmio_always_on) {
+ pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
+ if (orig_cmd & PCI_COMMAND_DECODE_ENABLE)
+ pci_write_config_word(dev, PCI_COMMAND,
+ orig_cmd &
+ ~PCI_COMMAND_DECODE_ENABLE);
+ }
+
+ /* fetch amount of address space needed by this PCI device */
+ pci_read_config_dword(dev, reg, &orig_bar);
+ pci_write_config_dword(dev, reg, ~0);
+ pci_read_config_dword(dev, reg, &sz);
+ pci_write_config_dword(dev, reg, orig_bar);
+
+ /* if no size is set, or size is invalid, or this BAR is for
+ I/O, then leave this BAR untouched */
+ if (!sz || sz == 0xffffffff || (sz & PCI_BASE_ADDRESS_SPACE_IO))
+ goto out;
+
+ /* ignore prefetch memory and 64-bit BARs, for now */
+ if ((sz & PCI_BASE_ADDRESS_MEM_PREFETCH))
+ goto out;
+
+ if ((sz & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
+ PCI_BASE_ADDRESS_MEM_TYPE_64)
+ goto out;
+
+ requested_size = ~(((u32) PCI_BASE_ADDRESS_MEM_MASK) & sz) + 1;
+ assigned_addr = pci_static_enum_assign_space(setting, requested_size);
+ if (assigned_addr > 0)
+ pci_write_config_dword(dev, reg, assigned_addr);
+
+out:
+ if (!dev->mmio_always_on && (orig_cmd & PCI_COMMAND_DECODE_ENABLE))
+ pci_write_config_word(dev, PCI_COMMAND, orig_cmd);
+}
+
+/**
+ * pci_static_enum_set_mmio_bars() - scan each BAR for this device,
+ * reassigning MMIO memory spaces
+ * @dev: PCI device to override
+ * @setting: static enumeration profile of the device's upstream bus
+ */
+static void pci_static_enum_set_mmio_bars(struct pci_dev *dev, struct pci_static_enum_setting
+ *setting)
+{
+ unsigned int howmany, pos, reg;
+
+ switch (dev->hdr_type) {
+ case PCI_HEADER_TYPE_NORMAL:
+ howmany = 6;
+ break;
+ case PCI_HEADER_TYPE_BRIDGE:
+ howmany = 2;
+ break;
+ default:
+ howmany = 1;
+ break;
+ }
+
+ /* for MMIO bars, find first allocation that fits within
+ upstream's bus */
+ dev_dbg(&dev->dev, "Reassigning MMIO bars\n");
+ for (pos = 0; pos < howmany; pos++) {
+ reg = PCI_BASE_ADDRESS_0 + (pos << 2);
+ pci_static_enum_reset_mmio_bar(dev, setting, reg);
+ }
+}
+
+/**
* pci_static_enum_device() - override a device's memory
* configuration, according to its static enumeration profile
* @dev: PCI device to override
@@ -365,6 +525,7 @@ static void pci_static_enum_set_bridge_memory(struct pci_dev *dev, struct pci_st
void pci_static_enum_device(struct pci_dev *dev)
{
struct pci_static_enum_setting *setting;
+ struct pci_dev *parent;
/* if dev is a bridge, set its memory regions */
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
@@ -374,4 +535,18 @@ void pci_static_enum_device(struct pci_dev *dev)
if (setting && setting->bridgemem_start)
pci_static_enum_set_bridge_memory(dev, setting);
}
+
+ /*
+ * if dev's parent bus has a static enumeration profile, then
+ * reassign BARS to fit within the parent's memory regions
+ */
+ parent = pci_upstream_bridge(dev);
+
+ if (parent) {
+ setting = pci_static_enum_find_setting(pci_domain_nr(dev->bus),
+ parent->bus->number,
+ parent->devfn);
+ if (setting)
+ pci_static_enum_set_mmio_bars(dev, setting);
+ }
}
--
1.7.9.5
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