firmware: raspberrypi: Introduce vl805 init routine

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. The function this patch
introduces triggers the aforementioned process.

Link: https://lore.kernel.org/r/20200505161318.26200-3-nsaenzjulienne@suse.de
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index da26a58..a166ad0 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;
 
@@ -286,6 +290,63 @@ 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", },
        {},

diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index cc9cdbc..3025aca 100644 (file)
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -10,6 +10,7 @@
 #include <linux/of_device.h>
 
 struct rpi_firmware;
+struct pci_dev;
 
 enum rpi_firmware_property_status {
        RPI_FIRMWARE_STATUS_REQUEST = 0,
@@ -141,6 +142,7 @@ int rpi_firmware_property(struct rpi_firmware *fw,
 int rpi_firmware_property_list(struct rpi_firmware *fw,
                               void *data, size_t tag_size);
 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
+int rpi_firmware_init_vl805(struct pci_dev *pdev);
 #else
 static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
                                        void *data, size_t len)
@@ -158,6 +160,11 @@ static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware
 {
        return NULL;
 }
+
+static inline int rpi_firmware_init_vl805(struct pci_dev *pdev)
+{
+       return 0;
+}
 #endif
 
 #endif /* __SOC_RASPBERRY_FIRMWARE_H__ */