[PATCH V4 09/12] PCI/TPH: Add save/restore support for TPH
From: Wei Huang <hidden>
Date: 2024-08-22 20:43:16
Also in:
linux-doc, linux-pci, lkml
Subsystem:
pci subsystem, the rest · Maintainers:
Bjorn Helgaas, Linus Torvalds
From: Paul Luse <redacted> Save and restore the configuration space for TPH capability to preserve the settings during PCI reset. The settings include the TPH control register and the ST table if present. Co-developed-by: Wei Huang <redacted> Signed-off-by: Wei Huang <redacted> Co-developed-by: Jing Liu <redacted> Signed-off-by: Jing Liu <redacted> Reviewed-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Paul Luse <redacted> --- drivers/pci/pci.c | 2 ++ drivers/pci/pci.h | 4 +++ drivers/pci/pcie/tph.c | 62 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 68 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e3a49f66982d..1e4960994b1a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c@@ -1813,6 +1813,7 @@ 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);
@@ -1917,6 +1918,7 @@ void pci_restore_state(struct pci_dev *dev) pci_restore_vc_state(dev); pci_restore_rebar_state(dev); pci_restore_dpc_state(dev); + pci_restore_tph_state(dev); pci_restore_ptm_state(dev); pci_aer_clear_status(dev);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 289eddfe350b..d7c7f86e8705 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h@@ -572,8 +572,12 @@ 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_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_tph_init(struct pci_dev *dev) { } #endif
diff --git a/drivers/pci/pcie/tph.c b/drivers/pci/pcie/tph.c
index 5bd194fb425e..b228ef5b7948 100644
--- a/drivers/pci/pcie/tph.c
+++ b/drivers/pci/pcie/tph.c@@ -483,6 +483,68 @@ int pcie_tph_modes(struct pci_dev *pdev) } EXPORT_SYMBOL(pcie_tph_modes); +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_tph_init(struct pci_dev *pdev) { pdev->tph_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_TPH);
--
2.45.1