[v7,4/4] drm/loongson: Use acpi to get video bios.

diff --git a/drivers/gpu/drm/loongson/Makefile b/drivers/gpu/drm/loongson/Makefile
index b083854d789b..b774a91003d9 100644
--- a/drivers/gpu/drm/loongson/Makefile
+++ b/drivers/gpu/drm/loongson/Makefile
@@ -11,5 +11,6 @@  loongson-y := loongson_connector.o \
 	loongson_encoder.o \
 	loongson_i2c.o \
 	loongson_irq.o \
-	loongson_plane.o
+	loongson_plane.o \
+	loongson_vbios.o
 obj-$(CONFIG_DRM_LOONGSON) += loongson.o
diff --git a/drivers/gpu/drm/loongson/loongson_drv.c b/drivers/gpu/drm/loongson/loongson_drv.c
index 1d6f35e78813..1c212200f088 100644
--- a/drivers/gpu/drm/loongson/loongson_drv.c
+++ b/drivers/gpu/drm/loongson/loongson_drv.c
@@ -19,14 +19,28 @@ 
 #include <drm/drm_probe_helper.h>

 #include "loongson_drv.h"
+#include "loongson_vbios.h"
+
+/*
+ * Completed
+ * 1.Displays controller device initialization and display funcitons
+ * 2.I2c bus driver and DDC functions
+ * 3.Vblank and vsync interrupt support
+ * 4.Use acpi to get video bios
+ * Todo
+ * 1.Video bios parse functions
+ * 2.Hardware cursor driver
+ * 3.New device support as well as Loongson GPU
+ */

 /* Interface history:
  * 0.1 - original.
  * 0.2 - add i2c and connector detect.
  * 0.3 - Vblank and vsync interrupt support.
+ * 0.4 - Use acpi to get vbios.
  */
 #define DRIVER_MAJOR 0
-#define DRIVER_MINOR 3
+#define DRIVER_MINOR 4

 static const struct drm_mode_config_funcs loongson_mode_funcs = {
 	.fb_create = drm_gem_fb_create,
@@ -88,7 +102,10 @@  static int loongson_device_init(struct drm_device *dev)
 	if (!ldev->io)
 		return -ENOMEM;

-	ldev->num_crtc = 2;
+	if (!loongson_vbios_init(ldev)) {
+		DRM_WARN("Get vbios failed, enable two crtc\n");
+		ldev->num_crtc = 2;
+	}

 	ret = loongson_dc_gpio_init(ldev);
 	if (ret)
diff --git a/drivers/gpu/drm/loongson/loongson_drv.h b/drivers/gpu/drm/loongson/loongson_drv.h
index af47e68487fd..4e5cb5977c9a 100644
--- a/drivers/gpu/drm/loongson/loongson_drv.h
+++ b/drivers/gpu/drm/loongson/loongson_drv.h
@@ -109,6 +109,7 @@  struct loongson_device {
 	u32 num_crtc;
 	struct loongson_mode_info mode_info[2];
 	struct pci_dev *gpu_pdev; /* LS7A gpu device info */
+	void *vbios;

 	struct loongson_i2c i2c_bus[DC_MAX_I2C_BUS];
 };
diff --git a/drivers/gpu/drm/loongson/loongson_vbios.c b/drivers/gpu/drm/loongson/loongson_vbios.c
new file mode 100644
index 000000000000..2b3a2757102a
--- /dev/null
+++ b/drivers/gpu/drm/loongson/loongson_vbios.c
@@ -0,0 +1,62 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#include "loongson_drv.h"
+#include "loongson_vbios.h"
+
+#ifdef CONFIG_ACPI
+static bool read_bios_from_acpi(struct loongson_device *ldev)
+{
+	void *vaddr;
+	struct acpi_table_header *hdr;
+	struct acpi_viat_table *viat;
+	acpi_size tbl_size;
+
+	if (!ACPI_SUCCESS(acpi_get_table("VIAT", 1, &hdr)))
+		return false;
+
+	tbl_size = hdr->length;
+	if (tbl_size != sizeof(struct acpi_viat_table)) {
+		DRM_WARN("ACPI viat table present but broken(too short #1)\n");
+		return false;
+	}
+
+	viat = (struct acpi_viat_table *)hdr;
+	ldev->vbios = kmalloc(VBIOS_SIZE, GFP_KERNEL);
+	if (!ldev->vbios) {
+		kfree(ldev->vbios);
+		return false;
+	}
+
+	vaddr = phys_to_virt(viat->vbios_addr);
+	memcpy(ldev->vbios, vaddr, VBIOS_SIZE);
+	DRM_INFO("Get vbios from ACPI success!\n");
+
+	return true;
+}
+#else
+static bool read_bios_from_acpi(struct loongson_device *ldev)
+{
+	return false;
+}
+#endif
+
+bool loongson_vbios_init(struct loongson_device *ldev)
+{
+	int ret;
+	struct loongson_vbios *header;
+
+	ret = read_bios_from_acpi(ldev);
+	if (!ret)
+		return ret;
+
+	header = ldev->vbios;
+	ldev->num_crtc = header->crtc_num;
+
+	DRM_INFO("Loongson vbios version %d.%d crtc num %d.\n",
+		 header->version_major, header->version_minor, ldev->num_crtc);
+
+	return ret;
+}
diff --git a/drivers/gpu/drm/loongson/loongson_vbios.h b/drivers/gpu/drm/loongson/loongson_vbios.h
new file mode 100644
index 000000000000..b7d8ce15c6c5
--- /dev/null
+++ b/drivers/gpu/drm/loongson/loongson_vbios.h
@@ -0,0 +1,29 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#ifndef __LOONGSON_VBIOS_H__
+#define __LOONGSON_VBIOS_H__
+
+#include <linux/acpi.h>
+
+#define VBIOS_SIZE 0x40000
+
+struct loongson_vbios {
+	uint32_t version_major;
+	uint32_t version_minor;
+	uint32_t crtc_num;
+} __packed;
+
+#ifdef CONFIG_ACPI
+/* VBOIS INFO ADDRESS TABLE */
+struct acpi_viat_table {
+	struct acpi_table_header header;
+	u64 vbios_addr;
+} __packed;
+#endif
+
+bool loongson_vbios_init(struct loongson_device *ldev);
+
+#endif /* __LOONGSON_VBIOS_H__ */