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Subject[PATCH v3 2/5] PCI/DPC: Allow dpc_probe() even if DPC is handled in firmware
Date
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Error Disconnect Recover (EDR) support allows OS to handle the error
recovery even when DPC configuration is handled by firmware. So allow
dpc_probe() to continue even if firmware first mode is enabed. This is
a prepratory patch for adding EDR support.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
drivers/pci/pcie/dpc.c | 49 +++++++++++++++++++++++++++++++-----------
1 file changed, 36 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 7b77754a82de..0c9ce876e450 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -20,6 +20,8 @@ struct dpc_dev {
u16 cap_pos;
bool rp_extensions;
u8 rp_log_size;
+ /* Set True if DPC is handled in firmware */
+ bool firmware_dpc;
};

static const char * const rp_pio_error_string[] = {
@@ -67,6 +69,9 @@ void pci_save_dpc_state(struct pci_dev *dev)
if (!dpc)
return;

+ if (dpc->firmware_dpc)
+ return;
+
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
if (!save_state)
return;
@@ -88,6 +93,9 @@ void pci_restore_dpc_state(struct pci_dev *dev)
if (!dpc)
return;

+ if (dpc->firmware_dpc)
+ return;
+
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
if (!save_state)
return;
@@ -292,9 +300,6 @@ static int dpc_probe(struct pcie_device *dev)
int status;
u16 ctl, cap;

- if (pcie_aer_get_firmware_first(pdev))
- return -ENOTSUPP;
-
dpc = devm_kzalloc(device, sizeof(*dpc), GFP_KERNEL);
if (!dpc)
return -ENOMEM;
@@ -303,13 +308,25 @@ static int dpc_probe(struct pcie_device *dev)
dpc->dev = dev;
set_service_data(dev, dpc);

- status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
- dpc_handler, IRQF_SHARED,
- "pcie-dpc", dpc);
- if (status) {
- dev_warn(device, "request IRQ%d failed: %d\n", dev->irq,
- status);
- return status;
+ if (pcie_aer_get_firmware_first(pdev))
+ dpc->firmware_dpc = 1;
+
+ /*
+ * If DPC is handled in firmware and ACPI support is not enabled in OS,
+ * then its not useful to proceed with probe. So, return error.
+ */
+ if (dpc->firmware_dpc && !IS_ENABLED(CONFIG_ACPI))
+ return -ENODEV;
+
+ if (!dpc->firmware_dpc) {
+ status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
+ dpc_handler, IRQF_SHARED,
+ "pcie-dpc", dpc);
+ if (status) {
+ dev_warn(device, "request IRQ%d failed: %d\n", dev->irq,
+ status);
+ return status;
+ }
}

pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap);
@@ -324,9 +341,12 @@ static int dpc_probe(struct pcie_device *dev)
dpc->rp_log_size = 0;
}
}
-
- ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
- pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
+ if (!dpc->firmware_dpc) {
+ ctl = (ctl & 0xfff4) |
+ (PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN);
+ pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL,
+ ctl);
+ }

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),
@@ -344,6 +364,9 @@ static void dpc_remove(struct pcie_device *dev)
struct pci_dev *pdev = dev->port;
u16 ctl;

+ if (dpc->firmware_dpc)
+ return;
+
pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN);
pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
--
2.20.1
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