arm: a37xx: pci: Handle propagation of CRSSVE bit from PCIe Root Port
Now that PCI Bridge (PCIe Root Port) for Aardvark is emulated in U-Boot,
add support for handling and propagation of CRSSVE bit.
When CRSSVE bit is unset (default), driver has to reissue config
read/write request on CRS response.
CRSSVE bit is supported only when CRSVIS bit is provided in read-only
Root Capabilities register. So manually inject this CRSVIS bit into read
response for that register.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/pci/pci-aardvark.c b/drivers/pci/pci-aardvark.c
index 2481cbe..591bc8b 100644
--- a/drivers/pci/pci-aardvark.c
+++ b/drivers/pci/pci-aardvark.c
@@ -41,6 +41,7 @@
#define PCIE_CORE_CMD_MEM_IO_REQ_EN BIT(2)
#define PCIE_CORE_DEV_REV_REG 0x8
#define PCIE_CORE_EXP_ROM_BAR_REG 0x30
+#define PCIE_CORE_PCIEXP_CAP_OFF 0xc0
#define PCIE_CORE_DEV_CTRL_STATS_REG 0xc8
#define PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE (0 << 4)
#define PCIE_CORE_DEV_CTRL_STATS_SNOOP_DISABLE (0 << 11)
@@ -201,6 +202,7 @@
struct udevice *dev;
struct gpio_desc reset_gpio;
u32 cfgcache[0x34 - 0x10];
+ bool cfgcrssve;
};
static inline void advk_writel(struct pcie_advk *pcie, uint val, uint reg)
@@ -413,6 +415,18 @@
data |= PCI_HEADER_TYPE_BRIDGE << 16;
}
+ if ((offset & ~3) == PCIE_CORE_PCIEXP_CAP_OFF + PCI_EXP_RTCTL) {
+ /* CRSSVE bit is stored only in cache */
+ if (pcie->cfgcrssve)
+ data |= PCI_EXP_RTCTL_CRSSVE;
+ }
+
+ if ((offset & ~3) == PCIE_CORE_PCIEXP_CAP_OFF +
+ (PCI_EXP_RTCAP & ~3)) {
+ /* CRS is emulated below, so set CRSVIS capability */
+ data |= PCI_EXP_RTCAP_CRSVIS << 16;
+ }
+
*valuep = pci_conv_32_to_size(data, offset, size);
return 0;
@@ -423,13 +437,14 @@
* OS is allowed only for 4-byte PCI_VENDOR_ID config read request and
* only when CRSSVE bit in Root Port PCIe device is enabled. In all
* other error PCIe Root Complex must return all-ones.
- * Aardvark HW does not have Root Port PCIe device and U-Boot does not
- * implement emulation of this device.
+ *
* U-Boot currently does not support handling of CRS return value for
* PCI_VENDOR_ID config read request and also does not set CRSSVE bit.
- * Therefore disable returning CRS response for now.
+ * So it means that pcie->cfgcrssve is false. But the code is prepared
+ * for returning CRS, so that if U-Boot does support CRS in the future,
+ * it will work for Aardvark.
*/
- allow_crs = false;
+ allow_crs = pcie->cfgcrssve;
if (advk_readl(pcie, PIO_START)) {
dev_err(pcie->dev,
@@ -583,6 +598,9 @@
(offset == PCI_PRIMARY_BUS && size != PCI_SIZE_8))
pcie->sec_busno = (data >> 8) & 0xff;
+ if ((offset & ~3) == PCIE_CORE_PCIEXP_CAP_OFF + PCI_EXP_RTCTL)
+ pcie->cfgcrssve = data & PCI_EXP_RTCTL_CRSSVE;
+
return 0;
}