diff options
Diffstat (limited to 'drivers/firmware/google/framebuffer-coreboot.c')
| -rw-r--r-- | drivers/firmware/google/framebuffer-coreboot.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/drivers/firmware/google/framebuffer-coreboot.c b/drivers/firmware/google/framebuffer-coreboot.c new file mode 100644 index 000000000000..c68c9f56370f --- /dev/null +++ b/drivers/firmware/google/framebuffer-coreboot.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * framebuffer-coreboot.c + * + * Memory based framebuffer accessed through coreboot table. + * + * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com> + * Copyright 2017 Google Inc. + * Copyright 2017 Samuel Holland <samuel@sholland.org> + */ + +#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 <linux/sysfb.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, + }; + + /* + * On coreboot systems, the advertised LB_TAG_FRAMEBUFFER entry + * in the coreboot table should only be used if the payload did + * not pass a framebuffer information to the Linux kernel. + * + * If the global screen_info data has been filled, the Generic + * System Framebuffers (sysfb) will already register a platform + * device and pass that screen_info as platform_data to a driver + * that can scan-out using the system provided framebuffer. + */ + if (sysfb_handles_screen_info()) + return -ENODEV; + + if (!fb->physical_address) + return -ENODEV; + + 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) + 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 void framebuffer_remove(struct coreboot_device *dev) +{ + struct platform_device *pdev = dev_get_drvdata(&dev->dev); + + platform_device_unregister(pdev); +} + +static const struct coreboot_device_id framebuffer_ids[] = { + { .tag = CB_TAG_FRAMEBUFFER }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(coreboot, framebuffer_ids); + +static struct coreboot_driver framebuffer_driver = { + .probe = framebuffer_probe, + .remove = framebuffer_remove, + .drv = { + .name = "framebuffer", + }, + .id_table = framebuffer_ids, +}; +module_coreboot_driver(framebuffer_driver); + +MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>"); +MODULE_DESCRIPTION("Memory based framebuffer accessed through coreboot table"); +MODULE_LICENSE("GPL"); |