Merge tag 'pci-v5.8-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

[platform/kernel/linux-starfive.git] / drivers / firmware / raspberrypi.c

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index a3e8518..ef80988 100644 (file)
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -12,6 +12,8 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
 #include <soc/bcm2835/raspberrypi-firmware.h>
 
 #define MBOX_MSG(chan, data28)         (((data28) & ~0xf) | ((chan) & 0xf))
@@ -19,6 +21,8 @@
 #define MBOX_DATA28(msg)               ((msg) & ~0xf)
 #define MBOX_CHAN_PROPERTY             8
 
+#define VL805_PCI_CONFIG_VERSION_OFFSET                0x50
+
 static struct platform_device *rpi_hwmon;
 static struct platform_device *rpi_clk;
 
@@ -280,6 +284,63 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 }
 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 
+/*
+ * The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip that
+ * implements xHCI. After a PCI reset, VL805's firmware may either be loaded
+ * directly from an EEPROM or, if not present, by the SoC's co-processor,
+ * VideoCore. RPi4's VideoCore OS contains both the non public firmware load
+ * logic and the VL805 firmware blob. This function triggers the aforementioned
+ * process.
+ */
+int rpi_firmware_init_vl805(struct pci_dev *pdev)
+{
+       struct device_node *fw_np;
+       struct rpi_firmware *fw;
+       u32 dev_addr, version;
+       int ret;
+
+       fw_np = of_find_compatible_node(NULL, NULL,
+                                       "raspberrypi,bcm2835-firmware");
+       if (!fw_np)
+               return 0;
+
+       fw = rpi_firmware_get(fw_np);
+       of_node_put(fw_np);
+       if (!fw)
+               return -ENODEV;
+
+       /*
+        * Make sure we don't trigger a firmware load unnecessarily.
+        *
+        * If something went wrong with PCI, this whole exercise would be
+        * futile as VideoCore expects from us a configured PCI bus. Just take
+        * the faulty version (likely ~0) and let xHCI's registration fail
+        * further down the line.
+        */
+       pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
+       if (version)
+               goto exit;
+
+       dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
+                  PCI_FUNC(pdev->devfn) << 12;
+
+       ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
+                                   &dev_addr, sizeof(dev_addr));
+       if (ret)
+               return ret;
+
+       /* Wait for vl805 to startup */
+       usleep_range(200, 1000);
+
+       pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET,
+                             &version);
+exit:
+       pci_info(pdev, "VL805 firmware version %08x\n", version);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_init_vl805);
+
 static const struct of_device_id rpi_firmware_of_match[] = {
        { .compatible = "raspberrypi,bcm2835-firmware", },
        {},