[PATCH 5/7] drm/tegra: falcon: Add support for RISC-V external boot

[Mikko Perttunen]

Add support for loading and booting RISC-V firmwares on Falcons with
RISC-V hardware. The flow is mostly the same as for traditional
Falcons, with a few different registers and different firmware layout.

Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
---
 drivers/gpu/drm/tegra/falcon.c | 66 +++++++++++++++++++++++++++++++++++-------
 drivers/gpu/drm/tegra/falcon.h | 23 +++++++++++++++
 2 files changed, 79 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/tegra/falcon.c b/drivers/gpu/drm/tegra/falcon.c
index 17f616bbcb45..1172356b6af3 100644
--- a/drivers/gpu/drm/tegra/falcon.c
+++ b/drivers/gpu/drm/tegra/falcon.c
@@ -26,8 +26,12 @@ int falcon_wait_idle(struct falcon *falcon)
 {
 	u32 value;
 
-	return readl_poll_timeout(falcon->regs + FALCON_IDLESTATE, value,
-				  (value == 0), 10, 100000);
+	if (falcon->riscv)
+		return readl_poll_timeout(falcon->regs + RISCV_CPUCTL, value,
+					  (value & RISCV_CPUCTL_ACTIVE_STAT_ACTIVE), 10, 100000);
+	else
+		return readl_poll_timeout(falcon->regs + FALCON_IDLESTATE, value,
+					  (value == 0), 10, 100000);
 }
 
 static int falcon_dma_wait_not_full(struct falcon *falcon)
@@ -122,6 +126,17 @@ static int falcon_parse_firmware_image(struct falcon *falcon)
 	return 0;
 }
 
+static void falcon_parse_firmware_desc(struct falcon *falcon)
+{
+	struct falcon_fw_riscv_desc *desc =
+		(struct falcon_fw_riscv_desc *)falcon->firmware.desc_firmware->data;
+
+	falcon->firmware.code.offset = desc->code_offset;
+	falcon->firmware.code.size = desc->code_size;
+	falcon->firmware.data.offset = desc->data_offset;
+	falcon->firmware.data.size = desc->data_size;
+}
+
 int falcon_read_firmware(struct falcon *falcon, const char *name)
 {
 	int err;
@@ -133,7 +148,23 @@ int falcon_read_firmware(struct falcon *falcon, const char *name)
 
 	falcon->firmware.size = falcon->firmware.firmware->size;
 
+	if (falcon->riscv) {
+		/* Load separate descriptor */
+		char desc_name[128];
+
+		scnprintf(desc_name, sizeof(desc_name), "%s.desc", name);
+		err = request_firmware(&falcon->firmware.desc_firmware, desc_name, falcon->dev);
+		if (err < 0)
+			goto release_firmware;
+	}
+
 	return 0;
+
+release_firmware:
+	release_firmware(falcon->firmware.firmware);
+	falcon->firmware.firmware = NULL;
+
+	return err;
 }
 
 int falcon_load_firmware(struct falcon *falcon)
@@ -144,16 +175,22 @@ int falcon_load_firmware(struct falcon *falcon)
 	/* copy firmware image into local area. this also ensures endianness */
 	falcon_copy_firmware_image(falcon, firmware);
 
-	/* parse the image data */
-	err = falcon_parse_firmware_image(falcon);
-	if (err < 0) {
-		dev_err(falcon->dev, "failed to parse firmware image\n");
-		return err;
+	if (falcon->riscv) {
+		falcon_parse_firmware_desc(falcon);
+	} else {
+		err = falcon_parse_firmware_image(falcon);
+		if (err < 0) {
+			dev_err(falcon->dev, "failed to parse firmware image\n");
+			return err;
+		}
 	}
 
 	release_firmware(firmware);
 	falcon->firmware.firmware = NULL;
 
+	release_firmware(falcon->firmware.desc_firmware);
+	falcon->firmware.desc_firmware = NULL;
+
 	return 0;
 }
 
@@ -168,6 +205,9 @@ void falcon_exit(struct falcon *falcon)
 {
 	if (falcon->firmware.firmware)
 		release_firmware(falcon->firmware.firmware);
+
+	if (falcon->firmware.desc_firmware)
+		release_firmware(falcon->firmware.desc_firmware);
 }
 
 int falcon_boot(struct falcon *falcon)
@@ -229,9 +269,15 @@ int falcon_boot(struct falcon *falcon)
 			      FALCON_ITFEN_CTXEN,
 		      FALCON_ITFEN);
 
-	/* boot falcon */
-	falcon_writel(falcon, 0x00000000, FALCON_BOOTVEC);
-	falcon_writel(falcon, FALCON_CPUCTL_STARTCPU, FALCON_CPUCTL);
+	if (falcon->riscv) {
+		falcon_writel(falcon, RISCV_BCR_CTRL_CORE_SELECT_RISCV, RISCV_BCR_CTRL);
+		falcon_writel(falcon, 0x0, RISCV_BOOT_VECTOR_HI);
+		falcon_writel(falcon, 0x100000, RISCV_BOOT_VECTOR_LO);
+		falcon_writel(falcon, RISCV_CPUCTL_STARTCPU, RISCV_CPUCTL);
+	} else {
+		falcon_writel(falcon, 0x00000000, FALCON_BOOTVEC);
+		falcon_writel(falcon, FALCON_CPUCTL_STARTCPU, FALCON_CPUCTL);
+	}
 
 	err = falcon_wait_idle(falcon);
 	if (err < 0) {
diff --git a/drivers/gpu/drm/tegra/falcon.h b/drivers/gpu/drm/tegra/falcon.h
index 902bb7e4fd0f..37a17c6136b3 100644
--- a/drivers/gpu/drm/tegra/falcon.h
+++ b/drivers/gpu/drm/tegra/falcon.h
@@ -55,6 +55,16 @@
 
 #define FALCON_DMATRFFBOFFS			0x0000111c
 
+#define RISCV_BOOT_VECTOR_LO			0x00001780
+#define RISCV_BOOT_VECTOR_HI			0x00001784
+
+#define RISCV_CPUCTL				0x00001788
+#define RISCV_CPUCTL_STARTCPU			(1 << 0)
+#define RISCV_CPUCTL_ACTIVE_STAT_ACTIVE		(1 << 7)
+
+#define RISCV_BCR_CTRL				0x00001a68
+#define RISCV_BCR_CTRL_CORE_SELECT_RISCV	(1 << 4)
+
 struct falcon_fw_bin_header_v1 {
 	u32 magic;		/* 0x10de */
 	u32 version;		/* version of bin format (1) */
@@ -76,6 +86,14 @@ struct falcon_fw_os_header_v1 {
 	u32 data_size;
 };
 
+struct falcon_fw_riscv_desc {
+	u32 reserved[74];
+	u32 data_offset;
+	u32 data_size;
+	u32 code_offset;
+	u32 code_size;
+};
+
 struct falcon_firmware_section {
 	unsigned long offset;
 	size_t size;
@@ -84,6 +102,8 @@ struct falcon_firmware_section {
 struct falcon_firmware {
 	/* Firmware after it is read but not loaded */
 	const struct firmware *firmware;
+	/* RISC-V firmware descriptor */
+	const struct firmware *desc_firmware;
 
 	/* Raw firmware data */
 	dma_addr_t iova;
@@ -102,6 +122,9 @@ struct falcon {
 	struct device *dev;
 	void __iomem *regs;
 
+	/* Peregrine falcon, external boot */
+	bool riscv;
+
 	struct falcon_firmware firmware;
 };
 

-- 
2.53.0