[PATCH 5/5] firmware: coreboot: Add coreboot framebuffer driver
From: Samuel Holland
Date: Wed Jan 24 2018 - 20:42:00 EST
Register a simplefb framebuffer when the coreboot table contains a
framebuffer entry.
Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
drivers/firmware/google/Kconfig | 8 ++
drivers/firmware/google/Makefile | 1 +
drivers/firmware/google/coreboot_table.h | 22 +++++
drivers/firmware/google/framebuffer-coreboot.c | 115 +++++++++++++++++++++++++
4 files changed, 146 insertions(+)
create mode 100644 drivers/firmware/google/framebuffer-coreboot.c
diff --git a/drivers/firmware/google/Kconfig b/drivers/firmware/google/Kconfig
index f16b381a569c..a456a000048b 100644
--- a/drivers/firmware/google/Kconfig
+++ b/drivers/firmware/google/Kconfig
@@ -55,6 +55,14 @@ config GOOGLE_MEMCONSOLE_X86_LEGACY
the EBDA on Google servers. If found, this log is exported to
userland in the file /sys/firmware/log.
+config GOOGLE_FRAMEBUFFER_COREBOOT
+ tristate "Coreboot Framebuffer"
+ depends on FB_SIMPLE
+ depends on GOOGLE_COREBOOT_TABLE
+ help
+ This option enables the kernel to search for a framebuffer in
+ the coreboot table. If found, it is registered with simplefb.
+
config GOOGLE_MEMCONSOLE_COREBOOT
tristate "Firmware Memory Console"
depends on GOOGLE_COREBOOT_TABLE
diff --git a/drivers/firmware/google/Makefile b/drivers/firmware/google/Makefile
index dcd3675efcfc..d0b3fba96194 100644
--- a/drivers/firmware/google/Makefile
+++ b/drivers/firmware/google/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_GOOGLE_SMI) += gsmi.o
obj-$(CONFIG_GOOGLE_COREBOOT_TABLE) += coreboot_table.o
obj-$(CONFIG_GOOGLE_COREBOOT_TABLE_ACPI) += coreboot_table-acpi.o
obj-$(CONFIG_GOOGLE_COREBOOT_TABLE_OF) += coreboot_table-of.o
+obj-$(CONFIG_GOOGLE_FRAMEBUFFER_COREBOOT) += framebuffer-coreboot.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE) += memconsole.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE_COREBOOT) += memconsole-coreboot.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE_X86_LEGACY) += memconsole-x86-legacy.o
diff --git a/drivers/firmware/google/coreboot_table.h b/drivers/firmware/google/coreboot_table.h
index 26a3f3f3ac9c..8ad95a94481b 100644
--- a/drivers/firmware/google/coreboot_table.h
+++ b/drivers/firmware/google/coreboot_table.h
@@ -3,6 +3,7 @@
*
* Internal header for coreboot table access.
*
+ * Copyright 2014 Gerd Hoffmann <kraxel@xxxxxxxxxx>
* Copyright 2017 Google Inc.
* Copyright 2017 Samuel Holland <samuel@xxxxxxxxxxxx>
*
@@ -46,12 +47,33 @@ struct lb_cbmem_ref {
u64 cbmem_addr;
};
+/* Describes framebuffer setup by coreboot */
+struct lb_framebuffer {
+ u32 tag;
+ u32 size;
+
+ u64 physical_address;
+ u32 x_resolution;
+ u32 y_resolution;
+ u32 bytes_per_line;
+ u8 bits_per_pixel;
+ u8 red_mask_pos;
+ u8 red_mask_size;
+ u8 green_mask_pos;
+ u8 green_mask_size;
+ u8 blue_mask_pos;
+ u8 blue_mask_size;
+ u8 reserved_mask_pos;
+ u8 reserved_mask_size;
+};
+
/* A device, additionally with information from coreboot. */
struct coreboot_device {
struct device dev;
union {
struct coreboot_table_entry entry;
struct lb_cbmem_ref cbmem_ref;
+ struct lb_framebuffer framebuffer;
};
};
diff --git a/drivers/firmware/google/framebuffer-coreboot.c b/drivers/firmware/google/framebuffer-coreboot.c
new file mode 100644
index 000000000000..b8b49c067157
--- /dev/null
+++ b/drivers/firmware/google/framebuffer-coreboot.c
@@ -0,0 +1,115 @@
+/*
+ * framebuffer-coreboot.c
+ *
+ * Memory based framebuffer accessed through coreboot table.
+ *
+ * Copyright 2012-2013 David Herrmann <dh.herrmann@xxxxxxxxx>
+ * Copyright 2017 Google Inc.
+ * Copyright 2017 Samuel Holland <samuel@xxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2.0 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/platform_data/simplefb.h>
+#include <linux/platform_device.h>
+
+#include "coreboot_table.h"
+
+#define CB_TAG_FRAMEBUFFER 0x12
+
+static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
+
+static int framebuffer_probe(struct coreboot_device *dev)
+{
+ int i;
+ u32 length;
+ struct lb_framebuffer *fb = &dev->framebuffer;
+ struct platform_device *pdev;
+ struct resource res;
+ struct simplefb_platform_data pdata = {
+ .width = fb->x_resolution,
+ .height = fb->y_resolution,
+ .stride = fb->bytes_per_line,
+ .format = NULL,
+ };
+
+ for (i = 0; i < ARRAY_SIZE(formats); ++i) {
+ if (fb->bits_per_pixel == formats[i].bits_per_pixel &&
+ fb->red_mask_pos == formats[i].red.offset &&
+ fb->red_mask_size == formats[i].red.length &&
+ fb->green_mask_pos == formats[i].green.offset &&
+ fb->green_mask_size == formats[i].green.length &&
+ fb->blue_mask_pos == formats[i].blue.offset &&
+ fb->blue_mask_size == formats[i].blue.length &&
+ fb->reserved_mask_pos == formats[i].transp.offset &&
+ fb->reserved_mask_size == formats[i].transp.length)
+ pdata.format = formats[i].name;
+ }
+ if (!pdata.format)
+ return -ENODEV;
+
+ memset(&res, 0, sizeof(res));
+ res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ res.name = "Coreboot Framebuffer";
+ res.start = fb->physical_address;
+ length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
+ res.end = res.start + length - 1;
+ if (res.end <= res.start)
+ return -EINVAL;
+
+ pdev = platform_device_register_resndata(&dev->dev,
+ "simple-framebuffer", 0,
+ &res, 1, &pdata,
+ sizeof(pdata));
+ if (IS_ERR(pdev))
+ pr_warn("coreboot: could not register framebuffer\n");
+ else
+ dev_set_drvdata(&dev->dev, pdev);
+
+ return PTR_ERR_OR_ZERO(pdev);
+}
+
+static int framebuffer_remove(struct coreboot_device *dev)
+{
+ struct platform_device *pdev = dev_get_drvdata(&dev->dev);
+
+ platform_device_unregister(pdev);
+
+ return 0;
+}
+
+static struct coreboot_driver framebuffer_driver = {
+ .probe = framebuffer_probe,
+ .remove = framebuffer_remove,
+ .drv = {
+ .name = "framebuffer",
+ },
+ .tag = CB_TAG_FRAMEBUFFER,
+};
+
+static int __init coreboot_framebuffer_init(void)
+{
+ return coreboot_driver_register(&framebuffer_driver);
+}
+
+static void coreboot_framebuffer_exit(void)
+{
+ coreboot_driver_unregister(&framebuffer_driver);
+}
+
+module_init(coreboot_framebuffer_init);
+module_exit(coreboot_framebuffer_exit);
+
+MODULE_AUTHOR("Samuel Holland <samuel@xxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.13.6