pcie_tph_get_cpu_st() is added to allow a caller to retrieve Steering Tags for a target memory that is associated with a specific CPU. The ST tag is retrieved by invoking ACPI _DSM of the device's Root Port device. pcie_tph_set_st_entry() is added to support updating the device's Steering Tags. The tags will be written into the device's MSI-X table or the ST table located in the TPH Extended Capability space. 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/tph.c | 349 +++++++++++++++++++++++++++++++++++++++- include/linux/pci-tph.h | 23 +++ 2 files changed, 371 insertions(+), 1 deletion(-) diff --git a/drivers/pci/tph.c b/drivers/pci/tph.c index 6c6b500c2eaa..3285763a7c44 100644 --- a/drivers/pci/tph.c +++ b/drivers/pci/tph.c @@ -7,6 +7,8 @@ * Wei Huang <wei.huang2@xxxxxxx> */ #include <linux/pci.h> +#include <linux/pci-acpi.h> +#include <linux/msi.h> #include <linux/bitfield.h> #include <linux/pci-tph.h> @@ -15,6 +17,133 @@ /* System-wide TPH disabled */ static bool pci_tph_disabled; +#ifdef CONFIG_ACPI +/* + * The st_info struct defines the Steering Tag (ST) info returned by the + * firmware _DSM method defined in the approved ECN for PCI Firmware Spec, + * available at https://members.pcisig.com/wg/PCI-SIG/document/15470. + * + * @vm_st_valid: 8-bit ST for volatile memory is valid + * @vm_xst_valid: 16-bit extended ST for volatile memory is valid + * @vm_ph_ignore: 1 => PH was and will be ignored, 0 => PH should be supplied + * @vm_st: 8-bit ST for volatile mem + * @vm_xst: 16-bit extended ST for volatile mem + * @pm_st_valid: 8-bit ST for persistent memory is valid + * @pm_xst_valid: 16-bit extended ST for persistent memory is valid + * @pm_ph_ignore: 1 => PH was and will be ignored, 0 => PH should be supplied + * @pm_st: 8-bit ST for persistent mem + * @pm_xst: 16-bit extended ST 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 *info) +{ + switch (req_type) { + case PCI_TPH_REQ_TPH_ONLY: /* 8-bit tag */ + switch (mem_type) { + case TPH_MEM_TYPE_VM: + if (info->vm_st_valid) + return info->vm_st; + break; + case TPH_MEM_TYPE_PM: + if (info->pm_st_valid) + return info->pm_st; + break; + } + break; + case PCI_TPH_REQ_EXT_TPH: /* 16-bit tag */ + switch (mem_type) { + case TPH_MEM_TYPE_VM: + if (info->vm_xst_valid) + return info->vm_xst; + break; + case TPH_MEM_TYPE_PM: + if (info->pm_xst_valid) + return info->pm_xst; + break; + } + break; + default: + return 0; + } + + return 0; +} + +#define TPH_ST_DSM_FUNC_INDEX 0xF +static acpi_status tph_invoke_dsm(acpi_handle handle, u32 cpu_uid, + 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, all 0's */ + arg3[2].integer.type = ACPI_TYPE_INTEGER; + arg3[2].integer.value = 0; + + 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; +} +#endif + +/* Update the TPH Requester Enable field of TPH Control Register */ +static void set_ctrl_reg_req_en(struct pci_dev *pdev, u8 req_type) +{ + u32 reg; + + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, ®); + + reg &= ~PCI_TPH_CTRL_REQ_EN_MASK; + reg |= FIELD_PREP(PCI_TPH_CTRL_REQ_EN_MASK, req_type); + + pci_write_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, reg); +} + static u8 get_st_modes(struct pci_dev *pdev) { u32 reg; @@ -25,6 +154,37 @@ static u8 get_st_modes(struct pci_dev *pdev) return reg; } +static u32 get_st_table_loc(struct pci_dev *pdev) +{ + u32 reg; + + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CAP, ®); + + return FIELD_GET(PCI_TPH_CAP_LOC_MASK, reg); +} + +/* + * Return the size of ST table. If ST table is not in TPH Requester Extended + * Capability space, return 0. Otherwise return the ST Table Size + 1. + */ +static u16 get_st_table_size(struct pci_dev *pdev) +{ + u32 reg; + u32 loc; + + /* Check ST table location first */ + loc = get_st_table_loc(pdev); + + /* Convert loc to match with PCI_TPH_LOC_* defined in pci_regs.h */ + loc = FIELD_PREP(PCI_TPH_CAP_LOC_MASK, loc); + if (loc != PCI_TPH_LOC_CAP) + return 0; + + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CAP, ®); + + return FIELD_GET(PCI_TPH_CAP_ST_MASK, reg) + 1; +} + /* Return device's Root Port completer capability */ static u8 get_rp_completer_type(struct pci_dev *pdev) { @@ -43,6 +203,169 @@ static u8 get_rp_completer_type(struct pci_dev *pdev) return FIELD_GET(PCI_EXP_DEVCAP2_TPH_COMP_MASK, reg); } +/* Write ST to MSI-X vector control reg - Return 0 if OK, otherwise -errno */ +static int write_tag_to_msix(struct pci_dev *pdev, int msix_idx, u16 tag) +{ + struct msi_desc *msi_desc = NULL; + void __iomem *vec_ctrl; + u32 val, mask, st_val; + int err = 0; + + msi_lock_descs(&pdev->dev); + + /* Find the msi_desc entry with matching msix_idx */ + msi_for_each_desc(msi_desc, &pdev->dev, MSI_DESC_ASSOCIATED) { + if (msi_desc->msi_index == msix_idx) + break; + } + + if (!msi_desc) { + err = -ENXIO; + goto err_out; + } + + st_val = (u32)tag; + + /* Get the vector control register (offset 0xc) pointed by msix_idx */ + vec_ctrl = pdev->msix_base + msix_idx * PCI_MSIX_ENTRY_SIZE; + vec_ctrl += PCI_MSIX_ENTRY_VECTOR_CTRL; + + val = readl(vec_ctrl); + mask = PCI_MSIX_ENTRY_CTRL_ST_LOWER | PCI_MSIX_ENTRY_CTRL_ST_UPPER; + val &= ~mask; + val |= FIELD_PREP(mask, st_val); + writel(val, vec_ctrl); + + /* Read back to flush the update */ + val = readl(vec_ctrl); + +err_out: + msi_unlock_descs(&pdev->dev); + return err; +} + +/* Write tag to ST table - Return 0 if OK, otherwise -errno */ +static int write_tag_to_st_table(struct pci_dev *pdev, int index, u16 tag) +{ + int st_table_size; + int offset; + + /* Check if index is out of bound */ + st_table_size = get_st_table_size(pdev); + if (index >= st_table_size) + return -ENXIO; + + offset = pdev->tph_cap + PCI_TPH_BASE_SIZEOF + index * sizeof(u16); + + return pci_write_config_word(pdev, offset, tag); +} + +/** + * pcie_tph_get_cpu_st() - Retrieve Steering Tag for a target memory associated + * with a specific CPU + * @pdev: PCI device + * @mem_type: target memory type (volatile or persistent RAM) + * @cpu_uid: associated CPU id + * @tag: Steering Tag to be returned + * + * This function returns the Steering Tag for a target memory that is + * associated with a specific CPU as indicated by cpu_uid. + * + * Returns: 0 if success, otherwise negative value (-errno) + */ +int pcie_tph_get_cpu_st(struct pci_dev *pdev, enum tph_mem_type mem_type, + unsigned int cpu_uid, u16 *tag) +{ +#ifdef CONFIG_ACPI + struct pci_dev *rp; + acpi_handle rp_acpi_handle; + union st_info info; + + rp = pcie_find_root_port(pdev); + if (!rp || !rp->bus || !rp->bus->bridge) + return -ENODEV; + + rp_acpi_handle = ACPI_HANDLE(rp->bus->bridge); + + if (tph_invoke_dsm(rp_acpi_handle, cpu_uid, &info) != AE_OK) { + *tag = 0; + return -EINVAL; + } + + *tag = tph_extract_tag(mem_type, pdev->tph_req_type, &info); + + pci_dbg(pdev, "get steering tag: mem_type=%s, cpu_uid=%d, tag=%#04x\n", + (mem_type == TPH_MEM_TYPE_VM) ? "volatile" : "persistent", + cpu_uid, *tag); + + return 0; +#else + return -ENODEV; +#endif +} +EXPORT_SYMBOL(pcie_tph_get_cpu_st); + +/** + * pcie_tph_set_st_entry() - Set Steering Tag in the ST table entry + * @pdev: PCI device + * @index: ST table entry index + * @tag: Steering Tag to be written + * + * This function will figure out the proper location of ST table, either in the + * MSI-X table or in the TPH Extended Capability space, and write the Steering + * Tag into the ST entry pointed by index. + * + * Returns: 0 if success, otherwise negative value (-errno) + */ +int pcie_tph_set_st_entry(struct pci_dev *pdev, unsigned int index, u16 tag) +{ + u32 loc; + int err = 0; + + if (!pdev->tph_cap) + return -EINVAL; + + if (!pdev->tph_enabled) + return -EINVAL; + + /* No need to write tag if device is in "No ST Mode" */ + if (pdev->tph_mode == PCI_TPH_ST_NS_MODE) + return 0; + + /* Disable TPH before updating ST to avoid potential instability as + * cautioned in PCIe r6.2, sec 6.17.3, "ST Modes of Operation" + */ + set_ctrl_reg_req_en(pdev, PCI_TPH_REQ_DISABLE); + + loc = get_st_table_loc(pdev); + /* Convert loc to match with PCI_TPH_LOC_* defined in pci_regs.h */ + loc = FIELD_PREP(PCI_TPH_CAP_LOC_MASK, loc); + + switch (loc) { + case PCI_TPH_LOC_MSIX: + err = write_tag_to_msix(pdev, index, tag); + break; + case PCI_TPH_LOC_CAP: + err = write_tag_to_st_table(pdev, index, tag); + break; + default: + err = -EINVAL; + } + + if (err) { + pcie_disable_tph(pdev); + return err; + } + + set_ctrl_reg_req_en(pdev, pdev->tph_mode); + + pci_dbg(pdev, "set steering tag: %s table, index=%d, tag=%#04x\n", + (loc == PCI_TPH_LOC_MSIX) ? "MSI-X" : "ST", index, tag); + + return 0; +} +EXPORT_SYMBOL(pcie_tph_set_st_entry); + /** * pcie_disable_tph - Turn off TPH support for device * @pdev: PCI device @@ -140,6 +463,8 @@ EXPORT_SYMBOL(pcie_enable_tph); void pci_restore_tph_state(struct pci_dev *pdev) { struct pci_cap_saved_state *save_state; + int num_entries, i, offset; + u16 *st_entry; u32 *cap; if (!pdev->tph_cap) @@ -155,11 +480,21 @@ void pci_restore_tph_state(struct pci_dev *pdev) /* Restore control register and all ST entries */ cap = &save_state->cap.data[0]; pci_write_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, *cap++); + st_entry = (u16 *)cap; + offset = PCI_TPH_BASE_SIZEOF; + num_entries = get_st_table_size(pdev); + for (i = 0; i < num_entries; i++) { + pci_write_config_word(pdev, pdev->tph_cap + offset, + *st_entry++); + offset += sizeof(u16); + } } void pci_save_tph_state(struct pci_dev *pdev) { struct pci_cap_saved_state *save_state; + int num_entries, i, offset; + u16 *st_entry; u32 *cap; if (!pdev->tph_cap) @@ -175,6 +510,16 @@ void pci_save_tph_state(struct pci_dev *pdev) /* Save control register */ cap = &save_state->cap.data[0]; pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, cap++); + + /* Save all ST entries in extended capability structure */ + st_entry = (u16 *)cap; + offset = PCI_TPH_BASE_SIZEOF; + num_entries = get_st_table_size(pdev); + for (i = 0; i < num_entries; i++) { + pci_read_config_word(pdev, pdev->tph_cap + offset, + st_entry++); + offset += sizeof(u16); + } } void pci_no_tph(void) @@ -186,12 +531,14 @@ void pci_no_tph(void) void pci_tph_init(struct pci_dev *pdev) { + int num_entries; u32 save_size; pdev->tph_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_TPH); if (!pdev->tph_cap) return; - save_size = sizeof(u32); + num_entries = get_st_table_size(pdev); + save_size = sizeof(u32) + num_entries * sizeof(u16); pci_add_ext_cap_save_buffer(pdev, PCI_EXT_CAP_ID_TPH, save_size); } diff --git a/include/linux/pci-tph.h b/include/linux/pci-tph.h index 58654a334ffb..c3e806c13d64 100644 --- a/include/linux/pci-tph.h +++ b/include/linux/pci-tph.h @@ -9,10 +9,33 @@ #ifndef LINUX_PCI_TPH_H #define LINUX_PCI_TPH_H +/* + * According to the ECN for PCI Firmware Spec, Steering Tag can be different + * depending on the memory type: Volatile Memory or Persistent Memory. When a + * caller query about a target's Steering Tag, it must provide the target's + * tph_mem_type. ECN link: https://members.pcisig.com/wg/PCI-SIG/document/15470. + */ +enum tph_mem_type { + TPH_MEM_TYPE_VM, /* volatile memory */ + TPH_MEM_TYPE_PM /* persistent memory */ +}; + #ifdef CONFIG_PCIE_TPH +int pcie_tph_set_st_entry(struct pci_dev *pdev, + unsigned int index, u16 tag); +int pcie_tph_get_cpu_st(struct pci_dev *dev, + enum tph_mem_type mem_type, + unsigned int cpu_uid, u16 *tag); void pcie_disable_tph(struct pci_dev *pdev); int pcie_enable_tph(struct pci_dev *pdev, int mode); #else +static inline int pcie_tph_set_st_entry(struct pci_dev *pdev, + unsigned int index, u16 tag) +{ return -EINVAL; } +static inline int pcie_tph_get_cpu_st(struct pci_dev *dev, + enum tph_mem_type mem_type, + unsigned int cpu_uid, u16 *tag) +{ return -EINVAL; } static inline void pcie_disable_tph(struct pci_dev *pdev) { } static inline int pcie_enable_tph(struct pci_dev *pdev, int mode) { return -EINVAL; } -- 2.46.0
