drm/tegra: Add code for booting RISC-V based engines

Add helper code for booting RISC-V based engines where firmware is
located in a carveout.

Signed-off-by: Mikko Perttunen <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>

Author: cyndis

drivers/gpu/drm/tegra/Makefile

@@ -24,7 +24,8 @@ tegra-drm-y := \
 	gr3d.o \
 	falcon.o \
 	vic.o \
-	nvdec.o
+	nvdec.o \
+	riscv.o
 
 tegra-drm-y += trace.o
 

drivers/gpu/drm/tegra/riscv.c

@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022, NVIDIA Corporation.
+ */
+
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/iopoll.h>
+#include <linux/of.h>
+
+#include "riscv.h"
+
+#define RISCV_CPUCTL					0x4388
+#define RISCV_CPUCTL_STARTCPU_TRUE			(1 << 0)
+#define RISCV_BR_RETCODE				0x465c
+#define RISCV_BR_RETCODE_RESULT_V(x)			((x) & 0x3)
+#define RISCV_BR_RETCODE_RESULT_PASS_V			3
+#define RISCV_BCR_CTRL					0x4668
+#define RISCV_BCR_CTRL_CORE_SELECT_RISCV		(1 << 4)
+#define RISCV_BCR_DMACFG				0x466c
+#define RISCV_BCR_DMACFG_TARGET_LOCAL_FB		(0 << 0)
+#define RISCV_BCR_DMACFG_LOCK_LOCKED			(1 << 31)
+#define RISCV_BCR_DMAADDR_PKCPARAM_LO			0x4670
+#define RISCV_BCR_DMAADDR_PKCPARAM_HI			0x4674
+#define RISCV_BCR_DMAADDR_FMCCODE_LO			0x4678
+#define RISCV_BCR_DMAADDR_FMCCODE_HI			0x467c
+#define RISCV_BCR_DMAADDR_FMCDATA_LO			0x4680
+#define RISCV_BCR_DMAADDR_FMCDATA_HI			0x4684
+#define RISCV_BCR_DMACFG_SEC				0x4694
+#define RISCV_BCR_DMACFG_SEC_GSCID(v)			((v) << 16)
+
+static void riscv_writel(struct tegra_drm_riscv *riscv, u32 value, u32 offset)
+{
+	writel(value, riscv->regs + offset);
+}
+
+int tegra_drm_riscv_read_descriptors(struct tegra_drm_riscv *riscv)
+{
+	struct tegra_drm_riscv_descriptor *bl = &riscv->bl_desc;
+	struct tegra_drm_riscv_descriptor *os = &riscv->os_desc;
+	const struct device_node *np = riscv->dev->of_node;
+	int err;
+
+#define READ_PROP(name, location) \
+	err = of_property_read_u32(np, name, location); \
+	if (err) { \
+		dev_err(riscv->dev, "failed to read " name ": %d\n", err); \
+		return err; \
+	}
+
+	READ_PROP("nvidia,bl-manifest-offset", &bl->manifest_offset);
+	READ_PROP("nvidia,bl-code-offset", &bl->code_offset);
+	READ_PROP("nvidia,bl-data-offset", &bl->data_offset);
+	READ_PROP("nvidia,os-manifest-offset", &os->manifest_offset);
+	READ_PROP("nvidia,os-code-offset", &os->code_offset);
+	READ_PROP("nvidia,os-data-offset", &os->data_offset);
+#undef READ_PROP
+
+	if (bl->manifest_offset == 0 && bl->code_offset == 0 &&
+	    bl->data_offset == 0 && os->manifest_offset == 0 &&
+	    os->code_offset == 0 && os->data_offset == 0) {
+		dev_err(riscv->dev, "descriptors not available\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int tegra_drm_riscv_boot_bootrom(struct tegra_drm_riscv *riscv, phys_addr_t image_address,
+				 u32 gscid, const struct tegra_drm_riscv_descriptor *desc)
+{
+	phys_addr_t addr;
+	int err;
+	u32 val;
+
+	riscv_writel(riscv, RISCV_BCR_CTRL_CORE_SELECT_RISCV, RISCV_BCR_CTRL);
+
+	addr = image_address + desc->manifest_offset;
+	riscv_writel(riscv, lower_32_bits(addr >> 8), RISCV_BCR_DMAADDR_PKCPARAM_LO);
+	riscv_writel(riscv, upper_32_bits(addr >> 8), RISCV_BCR_DMAADDR_PKCPARAM_HI);
+
+	addr = image_address + desc->code_offset;
+	riscv_writel(riscv, lower_32_bits(addr >> 8), RISCV_BCR_DMAADDR_FMCCODE_LO);
+	riscv_writel(riscv, upper_32_bits(addr >> 8), RISCV_BCR_DMAADDR_FMCCODE_HI);
+
+	addr = image_address + desc->data_offset;
+	riscv_writel(riscv, lower_32_bits(addr >> 8), RISCV_BCR_DMAADDR_FMCDATA_LO);
+	riscv_writel(riscv, upper_32_bits(addr >> 8), RISCV_BCR_DMAADDR_FMCDATA_HI);
+
+	riscv_writel(riscv, RISCV_BCR_DMACFG_SEC_GSCID(gscid), RISCV_BCR_DMACFG_SEC);
+	riscv_writel(riscv,
+		RISCV_BCR_DMACFG_TARGET_LOCAL_FB | RISCV_BCR_DMACFG_LOCK_LOCKED, RISCV_BCR_DMACFG);
+
+	riscv_writel(riscv, RISCV_CPUCTL_STARTCPU_TRUE, RISCV_CPUCTL);
+
+	err = readl_poll_timeout(
+		riscv->regs + RISCV_BR_RETCODE, val,
+		RISCV_BR_RETCODE_RESULT_V(val) == RISCV_BR_RETCODE_RESULT_PASS_V,
+		10, 100000);
+	if (err) {
+		dev_err(riscv->dev, "error during bootrom execution. BR_RETCODE=%d\n", val);
+		return err;
+	}
+
+	return 0;
+}

drivers/gpu/drm/tegra/riscv.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022, NVIDIA Corporation.
+ */
+
+#ifndef DRM_TEGRA_RISCV_H
+#define DRM_TEGRA_RISCV_H
+
+struct tegra_drm_riscv_descriptor {
+	u32 manifest_offset;
+	u32 code_offset;
+	u32 code_size;
+	u32 data_offset;
+	u32 data_size;
+};
+
+struct tegra_drm_riscv {
+	/* User initializes */
+	struct device *dev;
+	void __iomem *regs;
+
+	struct tegra_drm_riscv_descriptor bl_desc;
+	struct tegra_drm_riscv_descriptor os_desc;
+};
+
+int tegra_drm_riscv_read_descriptors(struct tegra_drm_riscv *riscv);
+int tegra_drm_riscv_boot_bootrom(struct tegra_drm_riscv *riscv, phys_addr_t image_address,
+				 u32 gscid, const struct tegra_drm_riscv_descriptor *desc);
+
+#endif