PCI/DPC: Read RP PIO Log Size once at probe

The RP PIO Log Size is a read-only field in the DPC Capability, so it is
constant and known at probe-time, but previously we read it every time we
processed an RP PIO error.

Read it once in dpc_probe() (if the RP Extensions for DPC are supported)
and remember the size in struct dpc_dev.  No functional change intended.

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

diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
index 0bbdf513067ae263f4d676e001c7e28582febf36..17f60bd4ea5fda3210a0043c0f6ec436a2583ab8 100644 (file)
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -34,7 +34,6 @@ struct dpc_rp_pio_regs {
        struct rp_pio_header_log_regs header_log;
        u32 impspec_log;
        u32 tlp_prefix_log[4];
-       u32 log_size;
        u16 first_error;
 };
 
@@ -44,6 +43,7 @@ struct dpc_dev {
        u16                     cap_pos;
        bool                    rp_extensions;
        u32                     rp_pio_status;
+       u8                      rp_log_size;
 };
 
 static const char * const rp_pio_error_string[] = {
@@ -173,11 +173,12 @@ static void dpc_rp_pio_print_error(struct dpc_dev *dpc,
        }
 
        dpc_rp_pio_print_tlp_header(dev, &rp_pio->header_log);
-       if (rp_pio->log_size == 4)
+       if (dpc->rp_log_size == 4)
                return;
+
        dev_err(dev, "RP PIO ImpSpec Log %#010x\n", rp_pio->impspec_log);
 
-       for (i = 0; i < rp_pio->log_size - 5; i++)
+       for (i = 0; i < dpc->rp_log_size - 5; i++)
                dev_err(dev, "TLP Prefix Header: dw%d, %#010x\n", i,
                        rp_pio->tlp_prefix_log[i]);
 }
@@ -186,7 +187,6 @@ static void dpc_rp_pio_get_info(struct dpc_dev *dpc,
                                struct dpc_rp_pio_regs *rp_pio)
 {
        struct pci_dev *pdev = dpc->dev->port;
-       struct device *dev = &dpc->dev->device;
        int i;
        u16 cap = dpc->cap_pos, status;
 
@@ -206,13 +206,8 @@ static void dpc_rp_pio_get_info(struct dpc_dev *dpc,
        pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
        rp_pio->first_error = (status & 0x1f00) >> 8;
 
-       pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap);
-       rp_pio->log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
-       if (rp_pio->log_size < 4 || rp_pio->log_size > 9) {
-               dev_err(dev, "RP PIO log size %u is invalid\n",
-                       rp_pio->log_size);
+       if (dpc->rp_log_size < 4)
                return;
-       }
 
        pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG,
                              &rp_pio->header_log.dw0);
@@ -222,12 +217,12 @@ static void dpc_rp_pio_get_info(struct dpc_dev *dpc,
                              &rp_pio->header_log.dw2);
        pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG + 12,
                              &rp_pio->header_log.dw3);
-       if (rp_pio->log_size == 4)
+       if (dpc->rp_log_size == 4)
                return;
 
        pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_IMPSPEC_LOG,
                              &rp_pio->impspec_log);
-       for (i = 0; i < rp_pio->log_size - 5; i++)
+       for (i = 0; i < dpc->rp_log_size - 5; i++)
                pci_read_config_dword(pdev,
                        cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG,
                        &rp_pio->tlp_prefix_log[i]);
@@ -327,6 +322,14 @@ static int dpc_probe(struct pcie_device *dev)
        pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
 
        dpc->rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT);
+       if (dpc->rp_extensions) {
+               dpc->rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
+               if (dpc->rp_log_size < 4 || dpc->rp_log_size > 9) {
+                       dev_err(device, "RP PIO log size %u is invalid\n",
+                               dpc->rp_log_size);
+                       dpc->rp_log_size = 0;
+               }
+       }
 
        ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN;
        pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
@@ -334,7 +337,7 @@ static int dpc_probe(struct pcie_device *dev)
        dev_info(device, "DPC error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n",
                cap & PCI_EXP_DPC_IRQ, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
                FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
-               FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), (cap >> 8) & 0xf,
+               FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), dpc->rp_log_size,
                FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE));
        return status;
 }