PCI/DPC: Save and restore config state

This patch provides DPC save and restore capabilities.  This is necessary
for the driver to observe DPC events in the event the configuration space
needs to be restored after a reset.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0e54588825cbd611b2234da2eb0909ced2746bf6..d6bb56fbee6dfa4ff12cb6329aafc5daff242cdc 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1284,6 +1284,7 @@ int pci_save_state(struct pci_dev *dev)
        if (i != 0)
                return i;
 
+       pci_save_dpc_state(dev);
        return pci_save_vc_state(dev);
 }
 EXPORT_SYMBOL(pci_save_state);
@@ -1378,6 +1379,7 @@ void pci_restore_state(struct pci_dev *dev)
        pci_restore_ats_state(dev);
        pci_restore_vc_state(dev);
        pci_restore_rebar_state(dev);
+       pci_restore_dpc_state(dev);
 
        pci_cleanup_aer_error_status_regs(dev);
 

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6e0d1528d471c7970613680f88333480389b6ef4..b5af5642c6c9d139f5ae728b5a3645632ce94d0b 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -346,6 +346,14 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
 void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 #endif /* CONFIG_PCIEAER */
 
+#ifdef CONFIG_PCIE_DPC
+void pci_save_dpc_state(struct pci_dev *dev);
+void pci_restore_dpc_state(struct pci_dev *dev);
+#else
+static inline void pci_save_dpc_state(struct pci_dev *dev) {}
+static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
+#endif
+
 #ifdef CONFIG_PCI_ATS
 void pci_restore_ats_state(struct pci_dev *dev);
 #else

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index a1fd16bf1cab2db66129de96591f81cae13b55d9..ed815a28512e1fc76ec927341fb90486f992d394 100644 (file)
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -44,6 +44,58 @@ static const char * const rp_pio_error_string[] = {
        "Memory Request Completion Timeout",             /* Bit Position 18 */
 };
 
+static struct dpc_dev *to_dpc_dev(struct pci_dev *dev)
+{
+       struct device *device;
+
+       device = pcie_port_find_device(dev, PCIE_PORT_SERVICE_DPC);
+       if (!device)
+               return NULL;
+       return get_service_data(to_pcie_device(device));
+}
+
+void pci_save_dpc_state(struct pci_dev *dev)
+{
+       struct dpc_dev *dpc;
+       struct pci_cap_saved_state *save_state;
+       u16 *cap;
+
+       if (!pci_is_pcie(dev))
+               return;
+
+       dpc = to_dpc_dev(dev);
+       if (!dpc)
+               return;
+
+       save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
+       if (!save_state)
+               return;
+
+       cap = (u16 *)&save_state->cap.data[0];
+       pci_read_config_word(dev, dpc->cap_pos + PCI_EXP_DPC_CTL, cap);
+}
+
+void pci_restore_dpc_state(struct pci_dev *dev)
+{
+       struct dpc_dev *dpc;
+       struct pci_cap_saved_state *save_state;
+       u16 *cap;
+
+       if (!pci_is_pcie(dev))
+               return;
+
+       dpc = to_dpc_dev(dev);
+       if (!dpc)
+               return;
+
+       save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
+       if (!save_state)
+               return;
+
+       cap = (u16 *)&save_state->cap.data[0];
+       pci_write_config_word(dev, dpc->cap_pos + PCI_EXP_DPC_CTL, *cap);
+}
+
 static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
 {
        unsigned long timeout = jiffies + HZ;
@@ -67,18 +119,13 @@ static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
 static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 {
        struct dpc_dev *dpc;
-       struct pcie_device *pciedev;
-       struct device *devdpc;
-
        u16 cap;
 
        /*
         * DPC disables the Link automatically in hardware, so it has
         * already been reset by the time we get here.
         */
-       devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
-       pciedev = to_pcie_device(devdpc);
-       dpc = get_service_data(pciedev);
+       dpc = to_dpc_dev(pdev);
        cap = dpc->cap_pos;
 
        /*
@@ -259,6 +306,8 @@ static int dpc_probe(struct pcie_device *dev)
                FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
                FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), dpc->rp_log_size,
                FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE));
+
+       pci_add_ext_cap_save_buffer(pdev, PCI_EXT_CAP_ID_DPC, sizeof(u16));
        return status;
 }