[U-Boot] [PATCH 2/2] drivers: pci: add API to issue FLR on a PCI function, if supported

[Alex Marginean]

Signed-off-by: Alex Marginean <alexm.osslist at gmail.com>
---
 drivers/pci/pci-uclass.c | 25 +++++++++++++++++++++++++
 include/pci.h            | 11 +++++++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index 3204f156c3..12b171f9f2 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -1495,6 +1495,31 @@ int dm_pci_find_ext_capability(struct udevice *dev, int cap)
 	return dm_pci_find_next_ext_capability(dev, 0, cap);
 }
 
+int dm_pci_flr(struct udevice *dev)
+{
+	int pcie_off;
+	u32 cap;
+	u16 cmd;
+
+	/* look for PCI Express Capability */
+	pcie_off = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
+	if (!pcie_off)
+		return -ENOENT;
+
+	/* check FLR capability */
+	dm_pci_read_config32(dev, pcie_off + 4, &cap);
+	if (!(cap & PCI_X_CAP_FLR))
+		return -ENOENT;
+
+	dm_pci_read_config16(dev, pcie_off + 8, &cmd);
+	dm_pci_write_config16(dev, pcie_off + 8, cmd | PCI_X_CMD_FLR);
+
+	/* wait 100ms, per PCI spec */
+	mdelay(100);
+
+	return 0;
+}
+
 UCLASS_DRIVER(pci) = {
 	.id		= UCLASS_PCI,
 	.name		= "pci",
diff --git a/include/pci.h b/include/pci.h
index e1528bb257..c93e06dfb1 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -384,11 +384,14 @@
 
 /* PCI-X registers */
 
+#define  PCI_X_CAP_FLR		0x10000000 /* Function Level Reset capability */
+
 #define  PCI_X_CMD_DPERR_E      0x0001  /* Data Parity Error Recovery Enable */
 #define  PCI_X_CMD_ERO          0x0002  /* Enable Relaxed Ordering */
 #define  PCI_X_CMD_MAX_READ     0x0000  /* Max Memory Read Byte Count */
 #define  PCI_X_CMD_MAX_SPLIT    0x0030  /* Max Outstanding Split Transactions */
 #define  PCI_X_CMD_VERSION(x)   (((x) >> 12) & 3) /* Version */
+#define  PCI_X_CMD_FLR          0x8000  /* EP Function Level Reset */
 
 
 /* Slot Identification */
@@ -1411,6 +1414,14 @@ int dm_pci_find_next_ext_capability(struct udevice *dev, int start, int cap);
  */
 int dm_pci_find_ext_capability(struct udevice *dev, int cap);
 
+/**
+ * dm_pci_flr() - Perform FLR if the device suppoorts it
+ *
+ * @dev:	PCI device to reset
+ * @return:	0 if OK, -ENOENT if FLR is not supported by dev
+ */
+int dm_pci_flr(struct udevice *dev);
+
 #define dm_pci_virt_to_bus(dev, addr, flags) \
 	dm_pci_phys_to_bus(dev, (virt_to_phys(addr)), (flags))
 #define dm_pci_bus_to_virt(dev, addr, flags, len, map_flags) \
-- 
2.17.1