diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/pci/vc.c | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/drivers/pci/vc.c b/drivers/pci/vc.c new file mode 100644 index 000000000..5fc59ac31 --- /dev/null +++ b/drivers/pci/vc.c @@ -0,0 +1,428 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI Virtual Channel support + * + * Copyright (C) 2013 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + */ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/pci_regs.h> +#include <linux/types.h> + +#include "pci.h" + +/** + * pci_vc_save_restore_dwords - Save or restore a series of dwords + * @dev: device + * @pos: starting config space position + * @buf: buffer to save to or restore from + * @dwords: number of dwords to save/restore + * @save: whether to save or restore + */ +static void pci_vc_save_restore_dwords(struct pci_dev *dev, int pos, + u32 *buf, int dwords, bool save) +{ + int i; + + for (i = 0; i < dwords; i++, buf++) { + if (save) + pci_read_config_dword(dev, pos + (i * 4), buf); + else + pci_write_config_dword(dev, pos + (i * 4), *buf); + } +} + +/** + * pci_vc_load_arb_table - load and wait for VC arbitration table + * @dev: device + * @pos: starting position of VC capability (VC/VC9/MFVC) + * + * Set Load VC Arbitration Table bit requesting hardware to apply the VC + * Arbitration Table (previously loaded). When the VC Arbitration Table + * Status clears, hardware has latched the table into VC arbitration logic. + */ +static void pci_vc_load_arb_table(struct pci_dev *dev, int pos) +{ + u16 ctrl; + + pci_read_config_word(dev, pos + PCI_VC_PORT_CTRL, &ctrl); + pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL, + ctrl | PCI_VC_PORT_CTRL_LOAD_TABLE); + if (pci_wait_for_pending(dev, pos + PCI_VC_PORT_STATUS, + PCI_VC_PORT_STATUS_TABLE)) + return; + + pci_err(dev, "VC arbitration table failed to load\n"); +} + +/** + * pci_vc_load_port_arb_table - Load and wait for VC port arbitration table + * @dev: device + * @pos: starting position of VC capability (VC/VC9/MFVC) + * @res: VC resource number, ie. VCn (0-7) + * + * Set Load Port Arbitration Table bit requesting hardware to apply the Port + * Arbitration Table (previously loaded). When the Port Arbitration Table + * Status clears, hardware has latched the table into port arbitration logic. + */ +static void pci_vc_load_port_arb_table(struct pci_dev *dev, int pos, int res) +{ + int ctrl_pos, status_pos; + u32 ctrl; + + ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF); + status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF); + + pci_read_config_dword(dev, ctrl_pos, &ctrl); + pci_write_config_dword(dev, ctrl_pos, + ctrl | PCI_VC_RES_CTRL_LOAD_TABLE); + + if (pci_wait_for_pending(dev, status_pos, PCI_VC_RES_STATUS_TABLE)) + return; + + pci_err(dev, "VC%d port arbitration table failed to load\n", res); +} + +/** + * pci_vc_enable - Enable virtual channel + * @dev: device + * @pos: starting position of VC capability (VC/VC9/MFVC) + * @res: VC res number, ie. VCn (0-7) + * + * A VC is enabled by setting the enable bit in matching resource control + * registers on both sides of a link. We therefore need to find the opposite + * end of the link. To keep this simple we enable from the downstream device. + * RC devices do not have an upstream device, nor does it seem that VC9 do + * (spec is unclear). Once we find the upstream device, match the VC ID to + * get the correct resource, disable and enable on both ends. + */ +static void pci_vc_enable(struct pci_dev *dev, int pos, int res) +{ + int ctrl_pos, status_pos, id, pos2, evcc, i, ctrl_pos2, status_pos2; + u32 ctrl, header, cap1, ctrl2; + struct pci_dev *link = NULL; + + /* Enable VCs from the downstream device */ + if (!pci_is_pcie(dev) || !pcie_downstream_port(dev)) + return; + + ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF); + status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF); + + pci_read_config_dword(dev, ctrl_pos, &ctrl); + id = ctrl & PCI_VC_RES_CTRL_ID; + + pci_read_config_dword(dev, pos, &header); + + /* If there is no opposite end of the link, skip to enable */ + if (PCI_EXT_CAP_ID(header) == PCI_EXT_CAP_ID_VC9 || + pci_is_root_bus(dev->bus)) + goto enable; + + pos2 = pci_find_ext_capability(dev->bus->self, PCI_EXT_CAP_ID_VC); + if (!pos2) + goto enable; + + pci_read_config_dword(dev->bus->self, pos2 + PCI_VC_PORT_CAP1, &cap1); + evcc = cap1 & PCI_VC_CAP1_EVCC; + + /* VC0 is hardwired enabled, so we can start with 1 */ + for (i = 1; i < evcc + 1; i++) { + ctrl_pos2 = pos2 + PCI_VC_RES_CTRL + + (i * PCI_CAP_VC_PER_VC_SIZEOF); + status_pos2 = pos2 + PCI_VC_RES_STATUS + + (i * PCI_CAP_VC_PER_VC_SIZEOF); + pci_read_config_dword(dev->bus->self, ctrl_pos2, &ctrl2); + if ((ctrl2 & PCI_VC_RES_CTRL_ID) == id) { + link = dev->bus->self; + break; + } + } + + if (!link) + goto enable; + + /* Disable if enabled */ + if (ctrl2 & PCI_VC_RES_CTRL_ENABLE) { + ctrl2 &= ~PCI_VC_RES_CTRL_ENABLE; + pci_write_config_dword(link, ctrl_pos2, ctrl2); + } + + /* Enable on both ends */ + ctrl2 |= PCI_VC_RES_CTRL_ENABLE; + pci_write_config_dword(link, ctrl_pos2, ctrl2); +enable: + ctrl |= PCI_VC_RES_CTRL_ENABLE; + pci_write_config_dword(dev, ctrl_pos, ctrl); + + if (!pci_wait_for_pending(dev, status_pos, PCI_VC_RES_STATUS_NEGO)) + pci_err(dev, "VC%d negotiation stuck pending\n", id); + + if (link && !pci_wait_for_pending(link, status_pos2, + PCI_VC_RES_STATUS_NEGO)) + pci_err(link, "VC%d negotiation stuck pending\n", id); +} + +/** + * pci_vc_do_save_buffer - Size, save, or restore VC state + * @dev: device + * @pos: starting position of VC capability (VC/VC9/MFVC) + * @save_state: buffer for save/restore + * @save: if provided a buffer, this indicates what to do with it + * + * Walking Virtual Channel config space to size, save, or restore it + * is complicated, so we do it all from one function to reduce code and + * guarantee ordering matches in the buffer. When called with NULL + * @save_state, return the size of the necessary save buffer. When called + * with a non-NULL @save_state, @save determines whether we save to the + * buffer or restore from it. + */ +static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos, + struct pci_cap_saved_state *save_state, + bool save) +{ + u32 cap1; + char evcc, lpevcc, parb_size; + int i, len = 0; + u8 *buf = save_state ? (u8 *)save_state->cap.data : NULL; + + /* Sanity check buffer size for save/restore */ + if (buf && save_state->cap.size != + pci_vc_do_save_buffer(dev, pos, NULL, save)) { + pci_err(dev, "VC save buffer size does not match @0x%x\n", pos); + return -ENOMEM; + } + + pci_read_config_dword(dev, pos + PCI_VC_PORT_CAP1, &cap1); + /* Extended VC Count (not counting VC0) */ + evcc = cap1 & PCI_VC_CAP1_EVCC; + /* Low Priority Extended VC Count (not counting VC0) */ + lpevcc = (cap1 & PCI_VC_CAP1_LPEVCC) >> 4; + /* Port Arbitration Table Entry Size (bits) */ + parb_size = 1 << ((cap1 & PCI_VC_CAP1_ARB_SIZE) >> 10); + + /* + * Port VC Control Register contains VC Arbitration Select, which + * cannot be modified when more than one LPVC is in operation. We + * therefore save/restore it first, as only VC0 should be enabled + * after device reset. + */ + if (buf) { + if (save) + pci_read_config_word(dev, pos + PCI_VC_PORT_CTRL, + (u16 *)buf); + else + pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL, + *(u16 *)buf); + buf += 4; + } + len += 4; + + /* + * If we have any Low Priority VCs and a VC Arbitration Table Offset + * in Port VC Capability Register 2 then save/restore it next. + */ + if (lpevcc) { + u32 cap2; + int vcarb_offset; + + pci_read_config_dword(dev, pos + PCI_VC_PORT_CAP2, &cap2); + vcarb_offset = ((cap2 & PCI_VC_CAP2_ARB_OFF) >> 24) * 16; + + if (vcarb_offset) { + int size, vcarb_phases = 0; + + if (cap2 & PCI_VC_CAP2_128_PHASE) + vcarb_phases = 128; + else if (cap2 & PCI_VC_CAP2_64_PHASE) + vcarb_phases = 64; + else if (cap2 & PCI_VC_CAP2_32_PHASE) + vcarb_phases = 32; + + /* Fixed 4 bits per phase per lpevcc (plus VC0) */ + size = ((lpevcc + 1) * vcarb_phases * 4) / 8; + + if (size && buf) { + pci_vc_save_restore_dwords(dev, + pos + vcarb_offset, + (u32 *)buf, + size / 4, save); + /* + * On restore, we need to signal hardware to + * re-load the VC Arbitration Table. + */ + if (!save) + pci_vc_load_arb_table(dev, pos); + + buf += size; + } + len += size; + } + } + + /* + * In addition to each VC Resource Control Register, we may have a + * Port Arbitration Table attached to each VC. The Port Arbitration + * Table Offset in each VC Resource Capability Register tells us if + * it exists. The entry size is global from the Port VC Capability + * Register1 above. The number of phases is determined per VC. + */ + for (i = 0; i < evcc + 1; i++) { + u32 cap; + int parb_offset; + + pci_read_config_dword(dev, pos + PCI_VC_RES_CAP + + (i * PCI_CAP_VC_PER_VC_SIZEOF), &cap); + parb_offset = ((cap & PCI_VC_RES_CAP_ARB_OFF) >> 24) * 16; + if (parb_offset) { + int size, parb_phases = 0; + + if (cap & PCI_VC_RES_CAP_256_PHASE) + parb_phases = 256; + else if (cap & (PCI_VC_RES_CAP_128_PHASE | + PCI_VC_RES_CAP_128_PHASE_TB)) + parb_phases = 128; + else if (cap & PCI_VC_RES_CAP_64_PHASE) + parb_phases = 64; + else if (cap & PCI_VC_RES_CAP_32_PHASE) + parb_phases = 32; + + size = (parb_size * parb_phases) / 8; + + if (size && buf) { + pci_vc_save_restore_dwords(dev, + pos + parb_offset, + (u32 *)buf, + size / 4, save); + buf += size; + } + len += size; + } + + /* VC Resource Control Register */ + if (buf) { + int ctrl_pos = pos + PCI_VC_RES_CTRL + + (i * PCI_CAP_VC_PER_VC_SIZEOF); + if (save) + pci_read_config_dword(dev, ctrl_pos, + (u32 *)buf); + else { + u32 tmp, ctrl = *(u32 *)buf; + /* + * For an FLR case, the VC config may remain. + * Preserve enable bit, restore the rest. + */ + pci_read_config_dword(dev, ctrl_pos, &tmp); + tmp &= PCI_VC_RES_CTRL_ENABLE; + tmp |= ctrl & ~PCI_VC_RES_CTRL_ENABLE; + pci_write_config_dword(dev, ctrl_pos, tmp); + /* Load port arbitration table if used */ + if (ctrl & PCI_VC_RES_CTRL_ARB_SELECT) + pci_vc_load_port_arb_table(dev, pos, i); + /* Re-enable if needed */ + if ((ctrl ^ tmp) & PCI_VC_RES_CTRL_ENABLE) + pci_vc_enable(dev, pos, i); + } + buf += 4; + } + len += 4; + } + + return buf ? 0 : len; +} + +static struct { + u16 id; + const char *name; +} vc_caps[] = { { PCI_EXT_CAP_ID_MFVC, "MFVC" }, + { PCI_EXT_CAP_ID_VC, "VC" }, + { PCI_EXT_CAP_ID_VC9, "VC9" } }; + +/** + * pci_save_vc_state - Save VC state to pre-allocate save buffer + * @dev: device + * + * For each type of VC capability, VC/VC9/MFVC, find the capability and + * save it to the pre-allocated save buffer. + */ +int pci_save_vc_state(struct pci_dev *dev) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(vc_caps); i++) { + int pos, ret; + struct pci_cap_saved_state *save_state; + + pos = pci_find_ext_capability(dev, vc_caps[i].id); + if (!pos) + continue; + + save_state = pci_find_saved_ext_cap(dev, vc_caps[i].id); + if (!save_state) { + pci_err(dev, "%s buffer not found in %s\n", + vc_caps[i].name, __func__); + return -ENOMEM; + } + + ret = pci_vc_do_save_buffer(dev, pos, save_state, true); + if (ret) { + pci_err(dev, "%s save unsuccessful %s\n", + vc_caps[i].name, __func__); + return ret; + } + } + + return 0; +} + +/** + * pci_restore_vc_state - Restore VC state from save buffer + * @dev: device + * + * For each type of VC capability, VC/VC9/MFVC, find the capability and + * restore it from the previously saved buffer. + */ +void pci_restore_vc_state(struct pci_dev *dev) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(vc_caps); i++) { + int pos; + struct pci_cap_saved_state *save_state; + + pos = pci_find_ext_capability(dev, vc_caps[i].id); + save_state = pci_find_saved_ext_cap(dev, vc_caps[i].id); + if (!save_state || !pos) + continue; + + pci_vc_do_save_buffer(dev, pos, save_state, false); + } +} + +/** + * pci_allocate_vc_save_buffers - Allocate save buffers for VC caps + * @dev: device + * + * For each type of VC capability, VC/VC9/MFVC, find the capability, size + * it, and allocate a buffer for save/restore. + */ +void pci_allocate_vc_save_buffers(struct pci_dev *dev) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(vc_caps); i++) { + int len, pos = pci_find_ext_capability(dev, vc_caps[i].id); + + if (!pos) + continue; + + len = pci_vc_do_save_buffer(dev, pos, NULL, false); + if (pci_add_ext_cap_save_buffer(dev, vc_caps[i].id, len)) + pci_err(dev, "unable to preallocate %s save buffer\n", + vc_caps[i].name); + } +} |