[PATCH V4 09/12] PCI/TPH: Add save/restore support for TPH

Wei Huang
2024-08-22T20:43:16Z

From: Paul Luse <paul.e.luse@linux.intel.com>

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 <wei.huang2@amd.com>
Signed-off-by: Wei Huang <wei.huang2@amd.com>
Co-developed-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Paul Luse <paul.e.luse@linux.intel.com>
---
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