PCIe/NVMe Driver

[midnightveil]

This is very draft and a WIP, notably that it doesn't seem to work in RISC-V platforms¹. It also doesn't do any PCIe initialisation of which there is a significant amount.

Just creating this so this branch isn't lost.

U-Boot patch for PCI on imx8mm

diff --git a/configs/imx8mm_evk_defconfig b/configs/imx8mm_evk_defconfig
index 1a15292e2f..83e1999648 100644
--- a/configs/imx8mm_evk_defconfig
+++ b/configs/imx8mm_evk_defconfig
@@ -121,3 +121,20 @@ CONFIG_SDP_LOADADDR=0x40400000
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_SPL_USB_SDP_SUPPORT=y
 CONFIG_IMX_WATCHDOG=y
+
+
+CONFIG_CMD_PCI=y
+CONFIG_PCI=y
+CONFIG_PCIE_DW_IMX=y
+CONFIG_SYS_PCI_64BIT=y
+CONFIG_CMD_NVME=y
+CONFIG_NVME=y
+CONFIG_NVME_PCI=y
+CONFIG_DM_PCI_COMPAT=y
+CONFIG_PCIE_DW_COMMON=y
+CONFIG_DM_RESET=y
+CONFIG_PHY_IMX8M_PCIE=y
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
+CONFIG_SPL_SYSCON=y
+CONFIG_SPL_REGMAP=y
diff --git a/drivers/pci/pcie_dw_imx.c b/drivers/pci/pcie_dw_imx.c
index fdb463710b..bab65939da 100644
--- a/drivers/pci/pcie_dw_imx.c
+++ b/drivers/pci/pcie_dw_imx.c
@@ -212,8 +212,15 @@ static int pcie_dw_imx_probe(struct udevice *dev)

        if (pcie_link_up(priv, LINK_SPEED_GEN_1)) {
                printf("PCIE-%d: Link down\n", dev_seq(dev));
-               ret = -ENODEV;
-               goto err_link;
+               printf("...ignoring, trying again\n");
+               // ret = -ENODEV;
+               // goto err_link;
+
+               for (int i = 0; i < 10; i++) {
+                       if (wait_link_up(priv)) {
+                               mdelay(90);
+                       }
+               }
        }

        printf("PCIE-%d: Link up (Gen%d-x%d, Bus%d)\n", dev_seq(dev),

Footnotes

1. Infinite stream of interrupts (Star64) or only one interrupt even if not deasserted (QEMU). Not sure what's wrong with QEMU (maybe this?). Need to try figuring out the meaning of the platform-specific device registers for PCIe on the Star64 to see if there's some way of ACKing interrupts there (U-Boot somewhat knows about these) ↩