diff options
| -rw-r--r-- | Documentation/PCI/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/PCI/tph.rst | 132 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | Documentation/driver-api/pci/pci.rst | 3 | ||||
| -rw-r--r-- | drivers/pci/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/pci/Makefile | 1 | ||||
| -rw-r--r-- | drivers/pci/pci.c | 4 | ||||
| -rw-r--r-- | drivers/pci/pci.h | 12 | ||||
| -rw-r--r-- | drivers/pci/probe.c | 1 | ||||
| -rw-r--r-- | drivers/pci/tph.c | 547 | ||||
| -rw-r--r-- | include/linux/pci-tph.h | 44 | ||||
| -rw-r--r-- | include/linux/pci.h | 7 | ||||
| -rw-r--r-- | include/uapi/linux/pci_regs.h | 37 |
13 files changed, 794 insertions, 8 deletions
diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst index e73f84aebde3..5e7c4e6e726b 100644 --- a/Documentation/PCI/index.rst +++ b/Documentation/PCI/index.rst @@ -18,3 +18,4 @@ PCI Bus Subsystem pcieaer-howto endpoint/index boot-interrupts + tph diff --git a/Documentation/PCI/tph.rst b/Documentation/PCI/tph.rst new file mode 100644 index 000000000000..e8993be64fd6 --- /dev/null +++ b/Documentation/PCI/tph.rst @@ -0,0 +1,132 @@ +.. SPDX-License-Identifier: GPL-2.0 + + +=========== +TPH Support +=========== + +:Copyright: 2024 Advanced Micro Devices, Inc. +:Authors: - Eric van Tassell <eric.vantassell@amd.com> + - Wei Huang <wei.huang2@amd.com> + + +Overview +======== + +TPH (TLP Processing Hints) is a PCIe feature that allows endpoint devices +to provide optimization hints for requests that target memory space. +These hints, in a format called Steering Tags (STs), are embedded in the +requester's TLP headers, enabling the system hardware, such as the Root +Complex, to better manage platform resources for these requests. + +For example, on platforms with TPH-based direct data cache injection +support, an endpoint device can include appropriate STs in its DMA +traffic to specify which cache the data should be written to. This allows +the CPU core to have a higher probability of getting data from cache, +potentially improving performance and reducing latency in data +processing. + + +How to Use TPH +============== + +TPH is presented as an optional extended capability in PCIe. The Linux +kernel handles TPH discovery during boot, but it is up to the device +driver to request TPH enablement if it is to be utilized. Once enabled, +the driver uses the provided API to obtain the Steering Tag for the +target memory and to program the ST into the device's ST table. + +Enable TPH support in Linux +--------------------------- + +To support TPH, the kernel must be built with the CONFIG_PCIE_TPH option +enabled. + +Manage TPH +---------- + +To enable TPH for a device, use the following function:: + + int pcie_enable_tph(struct pci_dev *pdev, int mode); + +This function enables TPH support for device with a specific ST mode. +Current supported modes include: + + * PCI_TPH_ST_NS_MODE - NO ST Mode + * PCI_TPH_ST_IV_MODE - Interrupt Vector Mode + * PCI_TPH_ST_DS_MODE - Device Specific Mode + +`pcie_enable_tph()` checks whether the requested mode is actually +supported by the device before enabling. The device driver can figure out +which TPH mode is supported and can be properly enabled based on the +return value of `pcie_enable_tph()`. + +To disable TPH, use the following function:: + + void pcie_disable_tph(struct pci_dev *pdev); + +Manage ST +--------- + +Steering Tags are platform specific. PCIe spec does not specify where STs +are from. Instead PCI Firmware Specification defines an ACPI _DSM method +(see the `Revised _DSM for Cache Locality TPH Features ECN +<https://members.pcisig.com/wg/PCI-SIG/document/15470>`_) for retrieving +STs for a target memory of various properties. This method is what is +supported in this implementation. + +To retrieve a Steering Tag for a target memory associated with a specific +CPU, use the following function:: + + int pcie_tph_get_cpu_st(struct pci_dev *pdev, enum tph_mem_type type, + unsigned int cpu_uid, u16 *tag); + +The `type` argument is used to specify the memory type, either volatile +or persistent, of the target memory. The `cpu_uid` argument specifies the +CPU where the memory is associated to. + +After the ST value is retrieved, the device driver can use the following +function to write the ST into the device:: + + int pcie_tph_set_st_entry(struct pci_dev *pdev, unsigned int index, + u16 tag); + +The `index` argument is the ST table entry index the ST tag will be +written into. `pcie_tph_set_st_entry()` 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 +the `index` argument. + +It is completely up to the driver to decide how to use these TPH +functions. For example a network device driver can use the TPH APIs above +to update the Steering Tag when interrupt affinity of a RX/TX queue has +been changed. Here is a sample code for IRQ affinity notifier: + +.. code-block:: c + + static void irq_affinity_notified(struct irq_affinity_notify *notify, + const cpumask_t *mask) + { + struct drv_irq *irq; + unsigned int cpu_id; + u16 tag; + + irq = container_of(notify, struct drv_irq, affinity_notify); + cpumask_copy(irq->cpu_mask, mask); + + /* Pick a right CPU as the target - here is just an example */ + cpu_id = cpumask_first(irq->cpu_mask); + + if (pcie_tph_get_cpu_st(irq->pdev, TPH_MEM_TYPE_VM, cpu_id, + &tag)) + return; + + if (pcie_tph_set_st_entry(irq->pdev, irq->msix_nr, tag)) + return; + } + +Disable TPH system-wide +----------------------- + +There is a kernel command line option available to control TPH feature: + * "notph": TPH will be disabled for all endpoint devices. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1518343bbe22..178995b07451 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4678,6 +4678,10 @@ nomio [S390] Do not use MIO instructions. norid [S390] ignore the RID field and force use of one PCI domain per PCI function + notph [PCIE] If the PCIE_TPH kernel config parameter + is enabled, this kernel boot option can be used + to disable PCIe TLP Processing Hints support + system-wide. pcie_aspm= [PCIE] Forcibly enable or ignore PCIe Active State Power Management. diff --git a/Documentation/driver-api/pci/pci.rst b/Documentation/driver-api/pci/pci.rst index aa40b1cc243b..59d86e827198 100644 --- a/Documentation/driver-api/pci/pci.rst +++ b/Documentation/driver-api/pci/pci.rst @@ -46,6 +46,9 @@ PCI Support Library .. kernel-doc:: drivers/pci/pci-sysfs.c :internal: +.. kernel-doc:: drivers/pci/tph.c + :export: + PCI Hotplug Support Library --------------------------- diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index e1c025698a28..2fbd379923fd 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -173,6 +173,15 @@ config PCI_PASID If unsure, say N. +config PCIE_TPH + bool "TLP Processing Hints" + help + This option adds support for PCIe TLP Processing Hints (TPH). + TPH allows endpoint devices to provide optimization hints, such as + desired caching behavior, for requests that target memory space. + These hints, called Steering Tags, can empower the system hardware + to optimize the utilization of platform resources. + config PCI_P2PDMA bool "PCI peer-to-peer transfer support" depends on ZONE_DEVICE diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index 39a07890abd1..67647f1880fb 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -36,6 +36,7 @@ obj-$(CONFIG_VGA_ARB) += vgaarb.o obj-$(CONFIG_PCI_DOE) += doe.o obj-$(CONFIG_PCI_DYNAMIC_OF_NODES) += of_property.o obj-$(CONFIG_PCI_NPEM) += npem.o +obj-$(CONFIG_PCIE_TPH) += tph.o # Endpoint library must be initialized before its users obj-$(CONFIG_PCI_ENDPOINT) += endpoint/ diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 880f7565acf3..43c9a0e029c9 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1828,6 +1828,7 @@ int pci_save_state(struct pci_dev *dev) pci_save_dpc_state(dev); pci_save_aer_state(dev); pci_save_ptm_state(dev); + pci_save_tph_state(dev); return pci_save_vc_state(dev); } EXPORT_SYMBOL(pci_save_state); @@ -1933,6 +1934,7 @@ void pci_restore_state(struct pci_dev *dev) pci_restore_rebar_state(dev); pci_restore_dpc_state(dev); pci_restore_ptm_state(dev); + pci_restore_tph_state(dev); pci_aer_clear_status(dev); pci_restore_aer_state(dev); @@ -6925,6 +6927,8 @@ static int __init pci_setup(char *str) pci_no_domains(); } else if (!strncmp(str, "noari", 5)) { pcie_ari_disabled = true; + } else if (!strncmp(str, "notph", 5)) { + pci_no_tph(); } else if (!strncmp(str, "cbiosize=", 9)) { pci_cardbus_io_size = memparse(str + 9, &str); } else if (!strncmp(str, "cbmemsize=", 10)) { diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 7531e4b005c6..2e40fc63ba31 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -638,6 +638,18 @@ static inline int pci_iov_bus_range(struct pci_bus *bus) #endif /* CONFIG_PCI_IOV */ +#ifdef CONFIG_PCIE_TPH +void pci_restore_tph_state(struct pci_dev *dev); +void pci_save_tph_state(struct pci_dev *dev); +void pci_no_tph(void); +void pci_tph_init(struct pci_dev *dev); +#else +static inline void pci_restore_tph_state(struct pci_dev *dev) { } +static inline void pci_save_tph_state(struct pci_dev *dev) { } +static inline void pci_no_tph(void) { } +static inline void pci_tph_init(struct pci_dev *dev) { } +#endif + #ifdef CONFIG_PCIE_PTM void pci_ptm_init(struct pci_dev *dev); void pci_save_ptm_state(struct pci_dev *dev); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8a7e58e20839..bf4c76ec8cd4 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2516,6 +2516,7 @@ static void pci_init_capabilities(struct pci_dev *dev) pci_dpc_init(dev); /* Downstream Port Containment */ pci_rcec_init(dev); /* Root Complex Event Collector */ pci_doe_init(dev); /* Data Object Exchange */ + pci_tph_init(dev); /* TLP Processing Hints */ pcie_report_downtraining(dev); pci_init_reset_methods(dev); diff --git a/drivers/pci/tph.c b/drivers/pci/tph.c new file mode 100644 index 000000000000..1e604fbbda65 --- /dev/null +++ b/drivers/pci/tph.c @@ -0,0 +1,547 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * TPH (TLP Processing Hints) support + * + * Copyright (C) 2024 Advanced Micro Devices, Inc. + * Eric Van Tassell <Eric.VanTassell@amd.com> + * Wei Huang <wei.huang2@amd.com> + */ +#include <linux/pci.h> +#include <linux/pci-acpi.h> +#include <linux/msi.h> +#include <linux/bitfield.h> +#include <linux/pci-tph.h> + +#include "pci.h" + +/* 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 PCI ACPI _DSM method (rev=0x7, func=0xF, "_DSM to Query Cache + * Locality TPH Features"), as specified in the approved ECN for PCI Firmware + * Spec and 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; + + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CAP, ®); + reg &= PCI_TPH_CAP_ST_NS | PCI_TPH_CAP_ST_IV | PCI_TPH_CAP_ST_DS; + + 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) +{ + struct pci_dev *rp; + u32 reg; + int ret; + + rp = pcie_find_root_port(pdev); + if (!rp) + return 0; + + ret = pcie_capability_read_dword(rp, PCI_EXP_DEVCAP2, ®); + if (ret) + return 0; + + 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) +{ +#ifdef CONFIG_PCI_MSI + struct msi_desc *msi_desc = NULL; + void __iomem *vec_ctrl; + u32 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; + } + + /* 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); + val &= ~PCI_MSIX_ENTRY_CTRL_ST; + val |= FIELD_PREP(PCI_MSIX_ENTRY_CTRL_ST, tag); + writel(val, vec_ctrl); + + /* Read back to flush the update */ + val = readl(vec_ctrl); + +err_out: + msi_unlock_descs(&pdev->dev); + return err; +#else + return -ENODEV; +#endif +} + +/* 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 + * + * Return the Steering Tag for a target memory that is associated with a + * specific CPU as indicated by cpu_uid. + * + * Return: 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 + * + * 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. + * + * Return: 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_* */ + 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 + * + * Return: none + */ +void pcie_disable_tph(struct pci_dev *pdev) +{ + if (!pdev->tph_cap) + return; + + if (!pdev->tph_enabled) + return; + + pci_write_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, 0); + + pdev->tph_mode = 0; + pdev->tph_req_type = 0; + pdev->tph_enabled = 0; +} +EXPORT_SYMBOL(pcie_disable_tph); + +/** + * pcie_enable_tph - Enable TPH support for device using a specific ST mode + * @pdev: PCI device + * @mode: ST mode to enable. Current supported modes include: + * + * - PCI_TPH_ST_NS_MODE: NO ST Mode + * - PCI_TPH_ST_IV_MODE: Interrupt Vector Mode + * - PCI_TPH_ST_DS_MODE: Device Specific Mode + * + * Check whether the mode is actually supported by the device before enabling + * and return an error if not. Additionally determine what types of requests, + * TPH or extended TPH, can be issued by the device based on its TPH requester + * capability and the Root Port's completer capability. + * + * Return: 0 on success, otherwise negative value (-errno) + */ +int pcie_enable_tph(struct pci_dev *pdev, int mode) +{ + u32 reg; + u8 dev_modes; + u8 rp_req_type; + + /* Honor "notph" kernel parameter */ + if (pci_tph_disabled) + return -EINVAL; + + if (!pdev->tph_cap) + return -EINVAL; + + if (pdev->tph_enabled) + return -EBUSY; + + /* Sanitize and check ST mode compatibility */ + mode &= PCI_TPH_CTRL_MODE_SEL_MASK; + dev_modes = get_st_modes(pdev); + if (!((1 << mode) & dev_modes)) + return -EINVAL; + + pdev->tph_mode = mode; + + /* Get req_type supported by device and its Root Port */ + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CAP, ®); + if (FIELD_GET(PCI_TPH_CAP_EXT_TPH, reg)) + pdev->tph_req_type = PCI_TPH_REQ_EXT_TPH; + else + pdev->tph_req_type = PCI_TPH_REQ_TPH_ONLY; + + rp_req_type = get_rp_completer_type(pdev); + + /* Final req_type is the smallest value of two */ + pdev->tph_req_type = min(pdev->tph_req_type, rp_req_type); + + if (pdev->tph_req_type == PCI_TPH_REQ_DISABLE) + return -EINVAL; + + /* Write them into TPH control register */ + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, ®); + + reg &= ~PCI_TPH_CTRL_MODE_SEL_MASK; + reg |= FIELD_PREP(PCI_TPH_CTRL_MODE_SEL_MASK, pdev->tph_mode); + + reg &= ~PCI_TPH_CTRL_REQ_EN_MASK; + reg |= FIELD_PREP(PCI_TPH_CTRL_REQ_EN_MASK, pdev->tph_req_type); + + pci_write_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, reg); + + pdev->tph_enabled = 1; + + return 0; +} +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) + return; + + if (!pdev->tph_enabled) + return; + + save_state = pci_find_saved_ext_cap(pdev, PCI_EXT_CAP_ID_TPH); + if (!save_state) + return; + + /* 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) + return; + + if (!pdev->tph_enabled) + return; + + save_state = pci_find_saved_ext_cap(pdev, PCI_EXT_CAP_ID_TPH); + if (!save_state) + return; + + /* 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) +{ + pci_tph_disabled = true; + + pr_info("PCIe TPH is disabled\n"); +} + +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; + + 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 new file mode 100644 index 000000000000..c3e806c13d64 --- /dev/null +++ b/include/linux/pci-tph.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * TPH (TLP Processing Hints) + * + * Copyright (C) 2024 Advanced Micro Devices, Inc. + * Eric Van Tassell <Eric.VanTassell@amd.com> + * Wei Huang <wei.huang2@amd.com> + */ +#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; } +#endif + +#endif /* LINUX_PCI_TPH_H */ diff --git a/include/linux/pci.h b/include/linux/pci.h index 5db9b0b2dca1..19147cb5bd9d 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -442,6 +442,7 @@ struct pci_dev { unsigned int ats_enabled:1; /* Address Translation Svc */ unsigned int pasid_enabled:1; /* Process Address Space ID */ unsigned int pri_enabled:1; /* Page Request Interface */ + unsigned int tph_enabled:1; /* TLP Processing Hints */ unsigned int is_managed:1; /* Managed via devres */ unsigned int is_msi_managed:1; /* MSI release via devres installed */ unsigned int needs_freset:1; /* Requires fundamental reset */ @@ -544,6 +545,12 @@ struct pci_dev { /* These methods index pci_reset_fn_methods[] */ u8 reset_methods[PCI_NUM_RESET_METHODS]; /* In priority order */ + +#ifdef CONFIG_PCIE_TPH + u16 tph_cap; /* TPH capability offset */ + u8 tph_mode; /* TPH mode */ + u8 tph_req_type; /* TPH requester type */ +#endif }; static inline struct pci_dev *pci_physfn(struct pci_dev *dev) diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index f3c9de0a497c..1601c7ed5fab 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -340,7 +340,8 @@ #define PCI_MSIX_ENTRY_UPPER_ADDR 0x4 /* Message Upper Address */ #define PCI_MSIX_ENTRY_DATA 0x8 /* Message Data */ #define PCI_MSIX_ENTRY_VECTOR_CTRL 0xc /* Vector Control */ -#define PCI_MSIX_ENTRY_CTRL_MASKBIT 0x00000001 +#define PCI_MSIX_ENTRY_CTRL_MASKBIT 0x00000001 /* Mask Bit */ +#define PCI_MSIX_ENTRY_CTRL_ST 0xffff0000 /* Steering Tag */ /* CompactPCI Hotswap Register */ @@ -659,6 +660,7 @@ #define PCI_EXP_DEVCAP2_ATOMIC_COMP64 0x00000100 /* 64b AtomicOp completion */ #define PCI_EXP_DEVCAP2_ATOMIC_COMP128 0x00000200 /* 128b AtomicOp completion */ #define PCI_EXP_DEVCAP2_LTR 0x00000800 /* Latency tolerance reporting */ +#define PCI_EXP_DEVCAP2_TPH_COMP_MASK 0x00003000 /* TPH completer support */ #define PCI_EXP_DEVCAP2_OBFF_MASK 0x000c0000 /* OBFF support mechanism */ #define PCI_EXP_DEVCAP2_OBFF_MSG 0x00040000 /* New message signaling */ #define PCI_EXP_DEVCAP2_OBFF_WAKE 0x00080000 /* Re-use WAKE# for OBFF */ @@ -1024,15 +1026,34 @@ #define PCI_DPA_CAP_SUBSTATE_MASK 0x1F /* # substates - 1 */ #define PCI_DPA_BASE_SIZEOF 16 /* size with 0 substates */ +/* TPH Completer Support */ +#define PCI_EXP_DEVCAP2_TPH_COMP_NONE 0x0 /* None */ +#define PCI_EXP_DEVCAP2_TPH_COMP_TPH_ONLY 0x1 /* TPH only */ +#define PCI_EXP_DEVCAP2_TPH_COMP_EXT_TPH 0x3 /* TPH and Extended TPH */ + /* TPH Requester */ #define PCI_TPH_CAP 4 /* capability register */ -#define PCI_TPH_CAP_LOC_MASK 0x600 /* location mask */ -#define PCI_TPH_LOC_NONE 0x000 /* no location */ -#define PCI_TPH_LOC_CAP 0x200 /* in capability */ -#define PCI_TPH_LOC_MSIX 0x400 /* in MSI-X */ -#define PCI_TPH_CAP_ST_MASK 0x07FF0000 /* ST table mask */ -#define PCI_TPH_CAP_ST_SHIFT 16 /* ST table shift */ -#define PCI_TPH_BASE_SIZEOF 0xc /* size with no ST table */ +#define PCI_TPH_CAP_ST_NS 0x00000001 /* No ST Mode Supported */ +#define PCI_TPH_CAP_ST_IV 0x00000002 /* Interrupt Vector Mode Supported */ +#define PCI_TPH_CAP_ST_DS 0x00000004 /* Device Specific Mode Supported */ +#define PCI_TPH_CAP_EXT_TPH 0x00000100 /* Ext TPH Requester Supported */ +#define PCI_TPH_CAP_LOC_MASK 0x00000600 /* ST Table Location */ +#define PCI_TPH_LOC_NONE 0x00000000 /* Not present */ +#define PCI_TPH_LOC_CAP 0x00000200 /* In capability */ +#define PCI_TPH_LOC_MSIX 0x00000400 /* In MSI-X */ +#define PCI_TPH_CAP_ST_MASK 0x07FF0000 /* ST Table Size */ +#define PCI_TPH_CAP_ST_SHIFT 16 /* ST Table Size shift */ +#define PCI_TPH_BASE_SIZEOF 0xc /* Size with no ST table */ + +#define PCI_TPH_CTRL 8 /* control register */ +#define PCI_TPH_CTRL_MODE_SEL_MASK 0x00000007 /* ST Mode Select */ +#define PCI_TPH_ST_NS_MODE 0x0 /* No ST Mode */ +#define PCI_TPH_ST_IV_MODE 0x1 /* Interrupt Vector Mode */ +#define PCI_TPH_ST_DS_MODE 0x2 /* Device Specific Mode */ +#define PCI_TPH_CTRL_REQ_EN_MASK 0x00000300 /* TPH Requester Enable */ +#define PCI_TPH_REQ_DISABLE 0x0 /* No TPH requests allowed */ +#define PCI_TPH_REQ_TPH_ONLY 0x1 /* TPH only requests allowed */ +#define PCI_TPH_REQ_EXT_TPH 0x3 /* Extended TPH requests allowed */ /* Downstream Port Containment */ #define PCI_EXP_DPC_CAP 0x04 /* DPC Capability */ |