The local device (host "bridge"?) on pci_mvebu controller reports
PCI_CLASS_MEMORY_OTHER in the class register.
This does not work in U-Boot, because U-Boot then tries to autoconfigure
this device in pci_auto.c. This causes the real connected PCIe device
not to work (in U-Boot nor in Linux).
Linux solves this by emulating PCI bridge device (see
drivers/pci/pci-bridge-emul.c in Linux). The Marvell vendor/device IDs
are used for this pci-bridge-emul device in Linux, but the actual
register accesses are emulated and the value of class register is
PCI_CLASS_BRIDGE_PCI.
The simplest solution here in my opinion is to just ignore the local
device in this driver's read/write methods. This fixes PCIe issues for
me.
Signed-off-by: Marek Behún <marek.be...@nic.cz>
Cc: Stefan Roese <s...@denx.de>
Cc: Anton Schubert <anton.schub...@gmx.de>
Cc: Dirk Eibach <dirk.eib...@gdsys.cc>
Cc: Mario Six <mario....@gdsys.cc>
Cc: Chris Packham <chris.pack...@alliedtelesis.co.nz>
Cc: Phil Sutter <p...@nwl.cc>
Cc: VlaoMao <vlao...@gmail.com>
---
drivers/pci/pci_mvebu.c | 59 +++++++++++++++++------------------------
1 file changed, 24 insertions(+), 35 deletions(-)
diff --git a/drivers/pci/pci_mvebu.c b/drivers/pci/pci_mvebu.c
index e21dc10c2f..653f445a0f 100644
--- a/drivers/pci/pci_mvebu.c
+++ b/drivers/pci/pci_mvebu.c
@@ -143,31 +143,31 @@ static int mvebu_pcie_read_config(struct udevice *bus,
pci_dev_t bdf,
struct mvebu_pcie *pcie = dev_get_platdata(bus);
int local_bus = PCI_BUS(pcie->dev);
int local_dev = PCI_DEV(pcie->dev);
+ int other_dev;
u32 reg;
u32 data;
debug("PCIE CFG read: (b,d,f)=(%2d,%2d,%2d) ",
PCI_BUS(bdf), PCI_DEV(bdf), PCI_FUNC(bdf));
- /* Only allow one other device besides the local one on the local bus */
- if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) != local_dev) {
- if (local_dev == 0 && PCI_DEV(bdf) != 1) {
- debug("- out of range\n");
- /*
- * If local dev is 0, the first other dev can
- * only be 1
- */
- *valuep = pci_get_ff(size);
- return 0;
- } else if (local_dev != 0 && PCI_DEV(bdf) != 0) {
- debug("- out of range\n");
- /*
- * If local dev is not 0, the first other dev can
- * only be 0
- */
- *valuep = pci_get_ff(size);
- return 0;
- }
+ /*
+ * The local device has PCI_CLASS_MEMORY_OTHER in the class register.
+ * This does not work for U-Boot because pci_auto.c tries to configure
+ * this as a device. This results in U-Boot/Linux being unable to access
+ * PCIe devices.
+ *
+ * Linux solves this by emulating a bridge (see
+ * drivers/pci/pci-bridge-emul.c in Linux).
+ *
+ * Let's ignore the local device in U-Boot.
+ *
+ * Also only allow one other device besides the (ignored) local one.
+ */
+
+ other_dev = local_dev ? 0 : 1;
+ if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) != other_dev) {
+ *valuep = pci_get_ff(size);
+ return 0;
}
/* write address */
@@ -187,28 +187,17 @@ static int mvebu_pcie_write_config(struct udevice *bus,
pci_dev_t bdf,
struct mvebu_pcie *pcie = dev_get_platdata(bus);
int local_bus = PCI_BUS(pcie->dev);
int local_dev = PCI_DEV(pcie->dev);
+ int other_dev;
u32 data;
debug("PCIE CFG write: (b,d,f)=(%2d,%2d,%2d) ",
PCI_BUS(bdf), PCI_DEV(bdf), PCI_FUNC(bdf));
debug("(addr,val)=(0x%04x, 0x%08lx)\n", offset, value);
- /* Only allow one other device besides the local one on the local bus */
- if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) != local_dev) {
- if (local_dev == 0 && PCI_DEV(bdf) != 1) {
- /*
- * If local dev is 0, the first other dev can
- * only be 1
- */
- return 0;
- } else if (local_dev != 0 && PCI_DEV(bdf) != 0) {
- /*
- * If local dev is not 0, the first other dev can
- * only be 0
- */
- return 0;
- }
- }
+ /* See the comment in mvebu_pcie_read_config */
+ other_dev = local_dev ? 0 : 1;
+ if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) != other_dev)
+ return 0;
writel(PCIE_CONF_ADDR(bdf, offset), pcie->base + PCIE_CONF_ADDR_OFF);
data = pci_conv_size_to_32(0, value, offset, size);
--
2.21.0
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