From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/pci/setup-bus.c | 191 ++++++++++++++++++++++++++++++-----------------
1 files changed, 120 insertions(+), 71 deletions(-)
diff --git a/kernel/drivers/pci/setup-bus.c b/kernel/drivers/pci/setup-bus.c
index 2ce6369..16d291e 100644
--- a/kernel/drivers/pci/setup-bus.c
+++ b/kernel/drivers/pci/setup-bus.c
@@ -1878,12 +1878,67 @@
add_size = size - new_size;
pci_dbg(bridge, "bridge window %pR shrunken by %pa\n", res,
&add_size);
+ } else {
+ return;
}
res->end = res->start + new_size - 1;
remove_from_list(add_list, res);
}
+static void remove_dev_resource(struct resource *avail, struct pci_dev *dev,
+ struct resource *res)
+{
+ resource_size_t size, align, tmp;
+
+ size = resource_size(res);
+ if (!size)
+ return;
+
+ align = pci_resource_alignment(dev, res);
+ align = align ? ALIGN(avail->start, align) - avail->start : 0;
+ tmp = align + size;
+ avail->start = min(avail->start + tmp, avail->end + 1);
+}
+
+static void remove_dev_resources(struct pci_dev *dev, struct resource *io,
+ struct resource *mmio,
+ struct resource *mmio_pref)
+{
+ int i;
+
+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+ struct resource *res = &dev->resource[i];
+
+ if (resource_type(res) == IORESOURCE_IO) {
+ remove_dev_resource(io, dev, res);
+ } else if (resource_type(res) == IORESOURCE_MEM) {
+
+ /*
+ * Make sure prefetchable memory is reduced from
+ * the correct resource. Specifically we put 32-bit
+ * prefetchable memory in non-prefetchable window
+ * if there is an 64-bit pretchable window.
+ *
+ * See comments in __pci_bus_size_bridges() for
+ * more information.
+ */
+ if ((res->flags & IORESOURCE_PREFETCH) &&
+ ((res->flags & IORESOURCE_MEM_64) ==
+ (mmio_pref->flags & IORESOURCE_MEM_64)))
+ remove_dev_resource(mmio_pref, dev, res);
+ else
+ remove_dev_resource(mmio, dev, res);
+ }
+ }
+}
+
+/*
+ * io, mmio and mmio_pref contain the total amount of bridge window space
+ * available. This includes the minimal space needed to cover all the
+ * existing devices on the bus and the possible extra space that can be
+ * shared with the bridges.
+ */
static void pci_bus_distribute_available_resources(struct pci_bus *bus,
struct list_head *add_list,
struct resource io,
@@ -1893,7 +1948,7 @@
unsigned int normal_bridges = 0, hotplug_bridges = 0;
struct resource *io_res, *mmio_res, *mmio_pref_res;
struct pci_dev *dev, *bridge = bus->self;
- resource_size_t io_per_hp, mmio_per_hp, mmio_pref_per_hp, align;
+ resource_size_t io_per_b, mmio_per_b, mmio_pref_per_b, align;
io_res = &bridge->resource[PCI_BRIDGE_IO_WINDOW];
mmio_res = &bridge->resource[PCI_BRIDGE_MEM_WINDOW];
@@ -1937,94 +1992,88 @@
normal_bridges++;
}
- /*
- * There is only one bridge on the bus so it gets all available
- * resources which it can then distribute to the possible hotplug
- * bridges below.
- */
- if (hotplug_bridges + normal_bridges == 1) {
- dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
- if (dev->subordinate)
- pci_bus_distribute_available_resources(dev->subordinate,
- add_list, io, mmio, mmio_pref);
+ if (!(hotplug_bridges + normal_bridges))
return;
+
+ /*
+ * Calculate the amount of space we can forward from "bus" to any
+ * downstream buses, i.e., the space left over after assigning the
+ * BARs and windows on "bus".
+ */
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (!dev->is_virtfn)
+ remove_dev_resources(dev, &io, &mmio, &mmio_pref);
}
- if (hotplug_bridges == 0)
- return;
-
/*
- * Calculate the total amount of extra resource space we can
- * pass to bridges below this one. This is basically the
- * extra space reduced by the minimal required space for the
- * non-hotplug bridges.
+ * If there is at least one hotplug bridge on this bus it gets all
+ * the extra resource space that was left after the reductions
+ * above.
+ *
+ * If there are no hotplug bridges the extra resource space is
+ * split between non-hotplug bridges. This is to allow possible
+ * hotplug bridges below them to get the extra space as well.
*/
+ if (hotplug_bridges) {
+ io_per_b = div64_ul(resource_size(&io), hotplug_bridges);
+ mmio_per_b = div64_ul(resource_size(&mmio), hotplug_bridges);
+ mmio_pref_per_b = div64_ul(resource_size(&mmio_pref),
+ hotplug_bridges);
+ } else {
+ io_per_b = div64_ul(resource_size(&io), normal_bridges);
+ mmio_per_b = div64_ul(resource_size(&mmio), normal_bridges);
+ mmio_pref_per_b = div64_ul(resource_size(&mmio_pref),
+ normal_bridges);
+ }
+
for_each_pci_bridge(dev, bus) {
- resource_size_t used_size;
struct resource *res;
-
- if (dev->is_hotplug_bridge)
- continue;
-
- /*
- * Reduce the available resource space by what the
- * bridge and devices below it occupy.
- */
- res = &dev->resource[PCI_BRIDGE_IO_WINDOW];
- align = pci_resource_alignment(dev, res);
- align = align ? ALIGN(io.start, align) - io.start : 0;
- used_size = align + resource_size(res);
- if (!res->parent)
- io.start = min(io.start + used_size, io.end + 1);
-
- res = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
- align = pci_resource_alignment(dev, res);
- align = align ? ALIGN(mmio.start, align) - mmio.start : 0;
- used_size = align + resource_size(res);
- if (!res->parent)
- mmio.start = min(mmio.start + used_size, mmio.end + 1);
-
- res = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
- align = pci_resource_alignment(dev, res);
- align = align ? ALIGN(mmio_pref.start, align) -
- mmio_pref.start : 0;
- used_size = align + resource_size(res);
- if (!res->parent)
- mmio_pref.start = min(mmio_pref.start + used_size,
- mmio_pref.end + 1);
- }
-
- io_per_hp = div64_ul(resource_size(&io), hotplug_bridges);
- mmio_per_hp = div64_ul(resource_size(&mmio), hotplug_bridges);
- mmio_pref_per_hp = div64_ul(resource_size(&mmio_pref),
- hotplug_bridges);
-
- /*
- * Go over devices on this bus and distribute the remaining
- * resource space between hotplug bridges.
- */
- for_each_pci_bridge(dev, bus) {
struct pci_bus *b;
b = dev->subordinate;
- if (!b || !dev->is_hotplug_bridge)
+ if (!b)
+ continue;
+ if (hotplug_bridges && !dev->is_hotplug_bridge)
continue;
+ res = &dev->resource[PCI_BRIDGE_IO_WINDOW];
+
/*
- * Distribute available extra resources equally between
- * hotplug-capable downstream ports taking alignment into
- * account.
+ * Make sure the split resource space is properly aligned
+ * for bridge windows (align it down to avoid going above
+ * what is available).
*/
- io.end = io.start + io_per_hp - 1;
- mmio.end = mmio.start + mmio_per_hp - 1;
- mmio_pref.end = mmio_pref.start + mmio_pref_per_hp - 1;
+ align = pci_resource_alignment(dev, res);
+ io.end = align ? io.start + ALIGN_DOWN(io_per_b, align) - 1
+ : io.start + io_per_b - 1;
+
+ /*
+ * The x_per_b holds the extra resource space that can be
+ * added for each bridge but there is the minimal already
+ * reserved as well so adjust x.start down accordingly to
+ * cover the whole space.
+ */
+ io.start -= resource_size(res);
+
+ res = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
+ align = pci_resource_alignment(dev, res);
+ mmio.end = align ? mmio.start + ALIGN_DOWN(mmio_per_b, align) - 1
+ : mmio.start + mmio_per_b - 1;
+ mmio.start -= resource_size(res);
+
+ res = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+ align = pci_resource_alignment(dev, res);
+ mmio_pref.end = align ? mmio_pref.start +
+ ALIGN_DOWN(mmio_pref_per_b, align) - 1
+ : mmio_pref.start + mmio_pref_per_b - 1;
+ mmio_pref.start -= resource_size(res);
pci_bus_distribute_available_resources(b, add_list, io, mmio,
mmio_pref);
- io.start += io_per_hp;
- mmio.start += mmio_per_hp;
- mmio_pref.start += mmio_pref_per_hp;
+ io.start += io.end + 1;
+ mmio.start += mmio.end + 1;
+ mmio_pref.start += mmio_pref.end + 1;
}
}
--
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