From: Dan Williams <dan.j.williams@xxxxxxxxx>
Rather than pass a boolean flag alongside @root to all the helper
functions that need to consider PCIe specifics, add is_pcie() and
is_cxl() helper functions to check the flavor of @root. This also
allows for dynamic fallback to PCIe _OSC in cases where an attempt to
use CXL _OXC fails. This can happen on CXL 1.1 platforms that publish
ACPI0016 devices to indicate CXL host bridges, but do not publish the
optional CXL _OSC method. CXL _OSC is mandatory for CXL 2.0 hosts.
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Robert Moore <robert.moore@xxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
---
include/acpi/acpi_bus.h | 1 +
drivers/acpi/pci_root.c | 62 +++++++++++++++++++++++++++++++----------
2 files changed, 48 insertions(+), 15 deletions(-)
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index ca88c4706f2b..768ef1584055 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -585,6 +585,7 @@ struct acpi_pci_root {
struct acpi_device * device;
struct pci_bus *bus;
u16 segment;
+ bool cxl_osc_disable;
struct resource secondary; /* downstream bus range */
u32 osc_support_set; /* _OSC state of support bits */
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index b76db99cced3..2d834504096b 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -170,20 +170,47 @@ static void decode_osc_control(struct acpi_pci_root *root, char *msg, u32 word)
ARRAY_SIZE(pci_osc_control_bit));
}
-static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
+static bool is_pcie(struct acpi_pci_root *root)
+{
+ return strcmp(acpi_device_hid(root->device), "PNP0A08") == 0;
+}
-static acpi_status acpi_pci_run_osc(acpi_handle handle,
+static bool is_cxl(struct acpi_pci_root *root)
+{
+ if (root->cxl_osc_disable)
+ return false;
+ return strcmp(acpi_device_hid(root->device), "ACPI0016") == 0;
+}
+
+static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
+static u8 cxl_osc_uuid_str[] = "68F2D50B-C469-4d8A-BD3D-941A103FD3FC";
+
+static char *to_uuid(struct acpi_pci_root *root)
+{
+ if (is_cxl(root))
+ return cxl_osc_uuid_str;
+ return pci_osc_uuid_str;
+}
+
+static int cap_length(struct acpi_pci_root *root)
+{
+ if (is_cxl(root))
+ return sizeof(u32) * 6;
+ return sizeof(u32) * 3;
+}
+
+static acpi_status acpi_pci_run_osc(struct acpi_pci_root *root,
const u32 *capbuf, u32 *retval)
{
struct acpi_osc_context context = {
- .uuid_str = pci_osc_uuid_str,
+ .uuid_str = to_uuid(root),
.rev = 1,
- .cap.length = 12,
+ .cap.length = cap_length(root),
.cap.pointer = (void *)capbuf,
};
acpi_status status;
- status = acpi_run_osc(handle, &context);
+ status = acpi_run_osc(root->device->handle, &context);
if (ACPI_SUCCESS(status)) {
*retval = *((u32 *)(context.ret.pointer + 8));
kfree(context.ret.pointer);
@@ -196,7 +223,7 @@ static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
u32 *control)
{
acpi_status status;
- u32 result, capbuf[3];
+ u32 result, capbuf[6];
support |= root->osc_support_set;
@@ -204,10 +231,18 @@ static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
capbuf[OSC_SUPPORT_DWORD] = support;
capbuf[OSC_CONTROL_DWORD] = *control | root->osc_control_set;
- status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
+retry:
+ status = acpi_pci_run_osc(root, capbuf, &result);
if (ACPI_SUCCESS(status)) {
root->osc_support_set = support;
*control = result;
+ } else if (is_cxl(root)) {
+ /*
+ * CXL _OSC is optional on CXL 1.1 hosts. Fall back to PCIe _OSC
+ * upon any failure using CXL _OSC.
+ */
+ root->cxl_osc_disable = true;
+ goto retry;
}
return status;
}
@@ -338,7 +373,7 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 s
u32 req = OSC_PCI_EXPRESS_CAPABILITY_CONTROL;
struct acpi_pci_root *root;
acpi_status status;
- u32 ctrl, capbuf[3];
+ u32 ctrl, capbuf[6];
if (!mask)
return AE_BAD_PARAMETER;
@@ -375,7 +410,7 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 s
capbuf[OSC_QUERY_DWORD] = 0;
capbuf[OSC_SUPPORT_DWORD] = root->osc_support_set;
capbuf[OSC_CONTROL_DWORD] = ctrl;
- status = acpi_pci_run_osc(handle, capbuf, mask);
+ status = acpi_pci_run_osc(root, capbuf, mask);
if (ACPI_FAILURE(status))
return status;
@@ -454,8 +489,7 @@ static bool os_control_query_checks(struct acpi_pci_root *root, u32 support)
return true;
}
-static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
- bool is_pcie)
+static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
{
u32 support, control = 0, requested = 0;
acpi_status status;
@@ -506,7 +540,7 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
*no_aspm = 1;
/* _OSC is optional for PCI host bridges */
- if ((status == AE_NOT_FOUND) && !is_pcie)
+ if ((status == AE_NOT_FOUND) && !is_pcie(root))
return;
if (control) {
@@ -529,7 +563,6 @@ static int acpi_pci_root_add(struct acpi_device *device,
acpi_handle handle = device->handle;
int no_aspm = 0;
bool hotadd = system_state == SYSTEM_RUNNING;
- bool is_pcie;
root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
if (!root)
@@ -587,8 +620,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);
- is_pcie = strcmp(acpi_device_hid(device), "PNP0A08") == 0;
- negotiate_os_control(root, &no_aspm, is_pcie);
+ negotiate_os_control(root, &no_aspm);
/*
* TBD: Need PCI interface for enumeration/configuration of roots.
--
2.35.1
