Add an API function to allow endpoint device drivers to retrieve
steering tags for a specific cpu_uid. This is achieved by invoking
ACPI _DSM on device's root port.
Co-developed-by: Eric Van Tassell <Eric.VanTassell@xxxxxxx>
Signed-off-by: Eric Van Tassell <Eric.VanTassell@xxxxxxx>
Signed-off-by: Wei Huang <wei.huang2@xxxxxxx>
Reviewed-by: Ajit Khaparde <ajit.khaparde@xxxxxxxxxxxx>
Reviewed-by: Somnath Kotur <somnath.kotur@xxxxxxxxxxxx>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@xxxxxxxxxxxx>
---
drivers/pci/pcie/tph.c | 162 ++++++++++++++++++++++++++++++++++++++++
include/linux/pci-tph.h | 12 +++
2 files changed, 174 insertions(+)
diff --git a/drivers/pci/pcie/tph.c b/drivers/pci/pcie/tph.c
index 7183370b0977..c805c8b1a7d2 100644
--- a/drivers/pci/pcie/tph.c
+++ b/drivers/pci/pcie/tph.c
@@ -7,12 +7,133 @@
* Wei Huang <wei.huang2@xxxxxxx>
*/
+#define pr_fmt(fmt) "TPH: " fmt
+#define dev_fmt pr_fmt
+
#include <linux/pci.h>
+#include <linux/pci-acpi.h>
#include <linux/bitfield.h>
#include <linux/pci-tph.h>
#include "../pci.h"
+/*
+ * The st_info struct defines the steering tag returned by the firmware _DSM
+ * method defined in PCI Firmware Spec r3.3, sect 4.6.15 "_DSM to Query Cache
+ * Locality TPH Features"
+ *
+ * @vm_st_valid: 8 bit tag for volatile memory is valid
+ * @vm_xst_valid: 16 bit tag for volatile memory is valid
+ * @vm_ignore: 1 => was and will be ignored, 0 => ph should be supplied
+ * @vm_st: 8 bit steering tag for volatile mem
+ * @vm_xst: 16 bit steering tag for volatile mem
+ * @pm_st_valid: 8 bit tag for persistent memory is valid
+ * @pm_xst_valid: 16 bit tag for persistent memory is valid
+ * @pm_ph_ignore: 1 => was and will be ignore, 0 => ph should be supplied
+ * @pm_st: 8 bit steering tag for persistent mem
+ * @pm_xst: 16 bit steering tag for persistent mem
+ */
+union st_info {
+ struct {
+ u64 vm_st_valid : 1;
+ u64 vm_xst_valid : 1;
+ u64 vm_ph_ignore : 1;
+ u64 rsvd1 : 5;
+ u64 vm_st : 8;
+ u64 vm_xst : 16;
+ u64 pm_st_valid : 1;
+ u64 pm_xst_valid : 1;
+ u64 pm_ph_ignore : 1;
+ u64 rsvd2 : 5;
+ u64 pm_st : 8;
+ u64 pm_xst : 16;
+ };
+ u64 value;
+};
+
+static u16 tph_extract_tag(enum tph_mem_type mem_type, u8 req_type,
+ union st_info *st_tag)
+{
+ switch (req_type) {
+ case PCI_TPH_REQ_TPH_ONLY: /* 8 bit tags */
+ switch (mem_type) {
+ case TPH_MEM_TYPE_VM:
+ if (st_tag->vm_st_valid)
+ return st_tag->vm_st;
+ break;
+ case TPH_MEM_TYPE_PM:
+ if (st_tag->pm_st_valid)
+ return st_tag->pm_st;
+ break;
+ }
+ break;
+ case PCI_TPH_REQ_EXT_TPH: /* 16 bit tags */
+ switch (mem_type) {
+ case TPH_MEM_TYPE_VM:
+ if (st_tag->vm_xst_valid)
+ return st_tag->vm_xst;
+ break;
+ case TPH_MEM_TYPE_PM:
+ if (st_tag->pm_xst_valid)
+ return st_tag->pm_xst;
+ break;
+ }
+ break;
+ default:
+ pr_err("invalid steering tag in ACPI _DSM\n");
+ return 0;
+ }
+
+ return 0;
+}
+
+#define TPH_ST_DSM_FUNC_INDEX 0xF
+static acpi_status tph_invoke_dsm(acpi_handle handle, u32 cpu_uid, u8 ph,
+ u8 target_type, bool cache_ref_valid,
+ u64 cache_ref, union st_info *st_out)
+{
+ union acpi_object arg3[3], in_obj, *out_obj;
+
+ if (!acpi_check_dsm(handle, &pci_acpi_dsm_guid, 7, BIT(TPH_ST_DSM_FUNC_INDEX)))
+ return AE_ERROR;
+
+ /* DWORD: feature ID (0 for processor cache ST query) */
+ arg3[0].integer.type = ACPI_TYPE_INTEGER;
+ arg3[0].integer.value = 0;
+
+ /* DWORD: target UID */
+ arg3[1].integer.type = ACPI_TYPE_INTEGER;
+ arg3[1].integer.value = cpu_uid;
+
+ /* QWORD: properties */
+ arg3[2].integer.type = ACPI_TYPE_INTEGER;
+ arg3[2].integer.value = ph & 3;
+ arg3[2].integer.value |= (target_type & 1) << 2;
+ arg3[2].integer.value |= (cache_ref_valid & 1) << 3;
+ arg3[2].integer.value |= (cache_ref << 32);
+
+ in_obj.type = ACPI_TYPE_PACKAGE;
+ in_obj.package.count = ARRAY_SIZE(arg3);
+ in_obj.package.elements = arg3;
+
+ out_obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 7,
+ TPH_ST_DSM_FUNC_INDEX, &in_obj);
+
+ if (!out_obj)
+ return AE_ERROR;
+
+ if (out_obj->type != ACPI_TYPE_BUFFER) {
+ ACPI_FREE(out_obj);
+ return AE_ERROR;
+ }
+
+ st_out->value = *((u64 *)(out_obj->buffer.pointer));
+
+ ACPI_FREE(out_obj);
+
+ return AE_OK;
+}
+
/* Update the ST Mode Select field of TPH Control Register */
static void set_ctrl_reg_mode_sel(struct pci_dev *pdev, u8 st_mode)
{
@@ -89,3 +210,44 @@ bool pcie_tph_intr_vec_supported(struct pci_dev *pdev)
return true;
}
EXPORT_SYMBOL(pcie_tph_intr_vec_supported);
+
+/**
+ * pcie_tph_get_st_from_acpi() - Retrieve steering tag for a specific CPU
+ * using platform ACPI _DSM
+ * @pdev: pci device
+ * @cpu_acpi_uid: the acpi cpu_uid.
+ * @mem_type: memory type (vram, nvram)
+ * @req_type: request type (disable, tph, extended tph)
+ * @tag: steering tag return value
+ *
+ * Return: 0 if success, otherwise errno
+ */
+int pcie_tph_get_st_from_acpi(struct pci_dev *pdev, unsigned int cpu_acpi_uid,
+ enum tph_mem_type mem_type, u8 req_type,
+ u16 *tag)
+{
+ struct pci_dev *rp;
+ acpi_handle rp_acpi_handle;
+ union st_info info;
+
+ if (!pdev->tph_cap)
+ return -ENODEV;
+
+ /* find ACPI handler for device's root port */
+ rp = pcie_find_root_port(pdev);
+ if (!rp || !rp->bus || !rp->bus->bridge)
+ return -ENODEV;
+ rp_acpi_handle = ACPI_HANDLE(rp->bus->bridge);
+
+ /* invoke _DSM to extract tag value */
+ if (tph_invoke_dsm(rp_acpi_handle, cpu_acpi_uid, 0, 0, false, 0, &info) != AE_OK) {
+ *tag = 0;
+ return -EINVAL;
+ }
+
+ *tag = tph_extract_tag(mem_type, req_type, &info);
+ pci_dbg(pdev, "%s: cpu=%d tag=%d\n", __func__, cpu_acpi_uid, *tag);
+
+ return 0;
+}
+EXPORT_SYMBOL(pcie_tph_get_st_from_acpi);
diff --git a/include/linux/pci-tph.h b/include/linux/pci-tph.h
index 854677651d81..b12a592f3d49 100644
--- a/include/linux/pci-tph.h
+++ b/include/linux/pci-tph.h
@@ -9,15 +9,27 @@
#ifndef LINUX_PCI_TPH_H
#define LINUX_PCI_TPH_H
+enum tph_mem_type {
+ TPH_MEM_TYPE_VM, /* volatile memory type */
+ TPH_MEM_TYPE_PM /* persistent memory type */
+};
+
#ifdef CONFIG_PCIE_TPH
void pcie_tph_disable(struct pci_dev *dev);
void pcie_tph_set_nostmode(struct pci_dev *dev);
bool pcie_tph_intr_vec_supported(struct pci_dev *dev);
+int pcie_tph_get_st_from_acpi(struct pci_dev *dev, unsigned int cpu_acpi_uid,
+ enum tph_mem_type tag_type, u8 req_enable,
+ u16 *tag);
#else
static inline void pcie_tph_disable(struct pci_dev *dev) {}
static inline void pcie_tph_set_nostmode(struct pci_dev *dev) {}
static inline bool pcie_tph_intr_vec_supported(struct pci_dev *dev)
{ return false; }
+static inline int pcie_tph_get_st_from_acpi(struct pci_dev *dev, unsigned int cpu_acpi_uid,
+ enum tph_mem_type tag_type, u8 req_enable,
+ u16 *tag)
+{ return false; }
#endif
#endif /* LINUX_PCI_TPH_H */
--
2.45.1
