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    <div><pre wrap="soft" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); overflow-wrap: break-word;">Add get video bios from the ACPI table.
Define new acpi table "VIAT" for loongson video bios.

Signed-off-by: Chenyang Li <lichenyang@loongson.cn>
---
 drivers/gpu/drm/loongson/Makefile         |  3 +-
 drivers/gpu/drm/loongson/loongson_drv.c   | 21 +++++++-
 drivers/gpu/drm/loongson/loongson_drv.h   |  1 +
 drivers/gpu/drm/loongson/loongson_vbios.c | 62 +++++++++++++++++++++++
 drivers/gpu/drm/loongson/loongson_vbios.h | 29 +++++++++++
 5 files changed, 113 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/loongson/loongson_vbios.c
 create mode 100644 drivers/gpu/drm/loongson/loongson_vbios.h

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 c9702970a037..1e777f4c1753 100644
--- a/drivers/gpu/drm/loongson/loongson_drv.c
+++ b/drivers/gpu/drm/loongson/loongson_drv.c
@@ -17,14 +17,28 @@
 #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,
@@ -86,7 +100,10 @@ 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 ec22dff89e88..eb13f2f68a17 100644
--- a/drivers/gpu/drm/loongson/loongson_drv.h
+++ b/drivers/gpu/drm/loongson/loongson_drv.h
@@ -107,6 +107,7 @@ 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..66f64f038d1f
--- /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..339498577395
--- /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__ */
-- 
2.25.1</pre></div>
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