arch/x86: drivers/display: add framebuffer driver w/ multiboot support

A basic display driver is added for a generic 32-bpp framebuffer.
Glue logic is added to the x86 arch to request the intitialization
of a linear framebuffer by the Multiboot loader (GRUB) and connect
it to this generic driver.

Signed-off-by: Charles E. Youse <charles.youse@intel.com>

CODEOWNERS

@@ -113,6 +113,7 @@
 /drivers/clock_control/*stm32f4*          @rsalveti @idlethread
 /drivers/counter/                         @nordic-krch
 /drivers/display/                         @vanwinkeljan
+/drivers/display/display_framebuf.c       @gnuless
 /drivers/dma/*sam0*                       @Sizurka
 /drivers/ethernet/                        @jukkar @tbursztyka @pfalcon
 /drivers/flash/                           @nashif
@@ -217,6 +218,7 @@
 /include/device.h                         @wentongwu @nashif
 /include/display.h                        @vanwinkeljan
 /include/display/                         @vanwinkeljan
+/include/display/framebuf.h               @gnuless
 /include/drivers/bluetooth/               @joerchan @jhedberg @Vudentz
 /include/drivers/led/ht16k33.h            @henrikbrixandersen
 /include/drivers/modem/                   @mike-scott

arch/x86/Kconfig

@@ -30,6 +30,29 @@ config X86_MULTIBOOT_INFO
 	  display driver) need to refer to information in this structure,
 	  and so set this option to preserve the data in a permanent location.
 
+if X86_MULTIBOOT
+
+config X86_MULTIBOOT_FRAMEBUF
+	bool "Multiboot framebuffer support"
+	default n
+	select DISPLAY
+	select FRAMEBUF_DISPLAY
+	select X86_MULTIBOOT_INFO
+
+if X86_MULTIBOOT_FRAMEBUF
+
+config X86_MULTIBOOT_FRAMEBUF_X
+	int "Multiboot framebuffer X pixels"
+	default 640
+
+config X86_MULTIBOOT_FRAMEBUF_Y
+	int "Multiboot framebuffer Y pixels"
+	default 480
+
+endif # X86_MULTIBOOT_FRAMEBUF
+
+endif # X86_MULTIBOOT
+
 source "arch/x86/core/Kconfig"
 
 #

arch/x86/core/crt0.S

@@ -507,34 +507,26 @@ z_x86_idt:
 
 
 #ifdef CONFIG_X86_MULTIBOOT
-	/* Multiboot header definition is needed for some bootloaders */
-
 	/*
 	 * The multiboot header must be in the first 8 Kb of the kernel image
 	 * (not including the ELF section header(s)) and be aligned on a
-	 * 4 byte boundary.
+	 * 4 byte boundary. See include/arch/x86/multiboot.h for more info.
 	 */
 
 	.balign 4,0x90
 
 	.long	X86_MULTIBOOT_HEADER_MAGIC
+	.long	X86_MULTIBOOT_HEADER_FLAGS
+	.long	-(X86_MULTIBOOT_HEADER_MAGIC + X86_MULTIBOOT_HEADER_FLAGS)
 
-	/*
+#ifdef CONFIG_X86_MULTIBOOT_FRAMEBUF
-	 * Flags = no bits are being set, specifically bit 16 is not being
+	.fill	5,4,0				/* (unused exec layout) */
-	 * set since the supplied kernel image is an ELF file, and the
+	.long	0				/* linear graphics mode */
-	 * multiboot loader shall use the information from the program and
+	.long	CONFIG_X86_MULTIBOOT_FRAMEBUF_X	/* width */
-	 * section header to load and boot the kernel image.
+	.long	CONFIG_X86_MULTIBOOT_FRAMEBUF_Y	/* height */
-	 */
+	.long	32				/* depth */
+#endif /* CONFIG_X86_MULTIBOOT_FRAMEBUF */
 
-	.long	0x00000000
-
-	/*
-	 * checksum = 32-bit unsigned value which, when added to the other
-	 * magic fields (i.e. "magic" and "flags"), must have a 32-bit
-	 * unsigned sum of zero.
-	 */
-
-	.long	-(X86_MULTIBOOT_HEADER_MAGIC + 0)
 #endif /* CONFIG_X86_MULTIBOOT */
 
 #ifdef CONFIG_SET_GDT

arch/x86/core/multiboot.c

@@ -11,4 +11,59 @@
 
 struct x86_multiboot_info x86_multiboot_info;
 
+#ifdef CONFIG_X86_MULTIBOOT_FRAMEBUF
+
+#include <display/framebuf.h>
+
+static struct framebuf_dev_data multiboot_framebuf_data = {
+	.width = CONFIG_X86_MULTIBOOT_FRAMEBUF_X,
+	.height = CONFIG_X86_MULTIBOOT_FRAMEBUF_Y
+};
+
+static int multiboot_framebuf_init(struct device *dev)
+{
+	struct framebuf_dev_data *data = FRAMEBUF_DATA(dev);
+	struct x86_multiboot_info *info = &x86_multiboot_info;
+
+	if ((info->flags & X86_MULTIBOOT_INFO_FLAGS_FB) &&
+	    (info->fb_width >= CONFIG_X86_MULTIBOOT_FRAMEBUF_X) &&
+	    (info->fb_height >= CONFIG_X86_MULTIBOOT_FRAMEBUF_Y) &&
+	    (info->fb_bpp == 32) && (info->fb_addr_hi == 0)) {
+		/*
+		 * We have a usable multiboot framebuffer - it is 32 bpp
+		 * and at least as large as the requested dimensions. Compute
+		 * the pitch and adjust the start address center our canvas.
+		 */
+
+		u16_t adj_x;
+		u16_t adj_y;
+		u32_t *buffer;
+
+		adj_x = info->fb_width - CONFIG_X86_MULTIBOOT_FRAMEBUF_X;
+		adj_y = info->fb_height - CONFIG_X86_MULTIBOOT_FRAMEBUF_Y;
+		buffer = (uint32_t *) info->fb_addr_lo;
+		data->pitch = (info->fb_pitch / 4) + adj_x;
+		adj_x /= 2;
+		adj_y /= 2;
+		buffer = (uint32_t *) info->fb_addr_lo;
+		buffer += adj_x;
+		buffer += adj_y * data->pitch;
+		data->buffer = buffer;
+		return 0;
+	} else {
+		return -ENOTSUP;
+	}
+}
+
+DEVICE_AND_API_INIT(multiboot_framebuf,
+		    "FRAMEBUF",
+		    multiboot_framebuf_init,
+		    &multiboot_framebuf_data,
+		    NULL,
+		    PRE_KERNEL_1,
+		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
+		    &framebuf_display_api);
+
+#endif /* CONFIG_X86_MULTIBOOT_FRAMEBUF */
+
 #endif /* CONFIG_X86_MULTIBOOT_INFO */

drivers/display/CMakeLists.txt

@@ -1,23 +1,22 @@
 # SPDX-License-Identifier: Apache-2.0
 
-
 zephyr_sources_ifdef(CONFIG_DISPLAY_MCUX_ELCDIF	display_mcux_elcdif.c)
-zephyr_sources_ifdef(CONFIG_GROVE_LCD_RGB grove_lcd_rgb.c)
+zephyr_sources_ifdef(CONFIG_GROVE_LCD_RGB	grove_lcd_rgb.c)
+zephyr_sources_ifdef(CONFIG_SSD1306		ssd1306.c)
+zephyr_sources_ifdef(CONFIG_SSD1673		ssd1673.c)
+zephyr_sources_ifdef(CONFIG_SDL_DISPLAY		display_sdl.c)
+zephyr_sources_ifdef(CONFIG_DUMMY_DISPLAY	display_dummy.c)
+zephyr_sources_ifdef(CONFIG_FRAMEBUF_DISPLAY	display_framebuf.c)
+zephyr_sources_ifdef(CONFIG_ILI9340		display_ili9340.c)
+
 zephyr_sources_ifdef(CONFIG_MICROBIT_DISPLAY
 	mb_display.c
 	mb_font.c
 )
-zephyr_sources_ifdef(CONFIG_ILI9340 display_ili9340.c)
 zephyr_sources_ifdef(CONFIG_ILI9340_LCD_ADAFRUIT_1480
 	display_ili9340_adafruit_1480.c
 )
+
 zephyr_sources_ifdef(CONFIG_ILI9340_LCD_SEEED_TFTV2
 	display_ili9340_seeed_tftv2.c
 )
-zephyr_sources_ifdef(CONFIG_SSD1306 ssd1306.c)
-zephyr_sources_ifdef(CONFIG_SSD1673 ssd1673.c)
-
-zephyr_sources_ifdef(CONFIG_SDL_DISPLAY display_sdl.c)
-
-zephyr_sources_ifdef(CONFIG_DUMMY_DISPLAY display_dummy.c)
-

drivers/display/Kconfig

@@ -22,11 +22,15 @@ source "drivers/display/Kconfig.mcux_elcdif"
 source "drivers/display/Kconfig.microbit"
 source "drivers/display/Kconfig.ili9340"
 source "drivers/display/Kconfig.sdl"
-
 source "drivers/display/Kconfig.ssd1306"
-
 source "drivers/display/Kconfig.ssd1673"
-
 source "drivers/display/Kconfig.dummy"
 
+config FRAMEBUF_DISPLAY
+	# Hidden, selected by client drivers.
+	bool
+	default n
+	help
+	  Enable framebuffer-based display 'helper' driver.
+
 endif # DISPLAY

drivers/display/display_framebuf.c

@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2019 Intel Corp.
+ *
+ * This is most of the display driver for a "standard" 32-bpp framebuffer.
+ * Device-specific drivers must still create the device instance and initialize
+ * it accordingly, but this driver implements most/all of the API functions.
+ * This code attempts to be endian-agnostic. It manipulates the framebuffer
+ * address space only in 32-bit words (and assumes those words are 0xAARRGGBB).
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <display.h>
+#include <display/framebuf.h>
+#include <string.h>
+
+static int framebuf_blanking_on(const struct device *dev)
+{
+	return -ENOTSUP;
+}
+
+static int framebuf_blanking_off(const struct device *dev)
+{
+	return -ENOTSUP;
+}
+
+static void *framebuf_get_framebuffer(const struct device *dev)
+{
+	return NULL;
+}
+
+static int framebuf_set_brightness(const struct device *dev,
+				   const u8_t brightness)
+{
+	return -ENOTSUP;
+}
+
+static int framebuf_set_contrast(const struct device *dev,
+				 const u8_t contrast)
+{
+	return -ENOTSUP;
+}
+
+static int framebuf_set_pixel_format(const struct device *dev,
+				     const enum display_pixel_format format)
+{
+	switch (format) {
+	case PIXEL_FORMAT_ARGB_8888:
+		return 0;
+	default:
+		return -ENOTSUP;
+	}
+}
+
+static int framebuf_set_orientation(const struct device *dev,
+				    const enum display_orientation orientation)
+{
+	switch (orientation) {
+	case DISPLAY_ORIENTATION_NORMAL:
+		return 0;
+	default:
+		return -ENOTSUP;
+	}
+}
+
+static void framebuf_get_capabilities(const struct device *dev,
+				      struct display_capabilities *caps)
+{
+	struct framebuf_dev_data *data = FRAMEBUF_DATA(dev);
+
+	caps->x_resolution = data->width;
+	caps->y_resolution = data->height;
+	caps->supported_pixel_formats = PIXEL_FORMAT_ARGB_8888;
+	caps->screen_info = 0;
+	caps->current_pixel_format = PIXEL_FORMAT_ARGB_8888;
+	caps->current_orientation = DISPLAY_ORIENTATION_NORMAL;
+}
+
+static int framebuf_write(const struct device *dev, const u16_t x,
+			  const u16_t y,
+			  const struct display_buffer_descriptor *desc,
+			  const void *buf)
+{
+	struct framebuf_dev_data *data = FRAMEBUF_DATA(dev);
+	u32_t *dst = data->buffer;
+	const u32_t *src = buf;
+	u32_t row;
+
+	dst += x;
+	dst += (y * data->pitch);
+
+	for (row = 0; row < desc->height; ++row) {
+		(void) memcpy(dst, src, desc->width * sizeof(u32_t));
+		dst += data->pitch;
+		src += desc->pitch;
+	}
+
+	return 0;
+}
+
+static int framebuf_read(const struct device *dev, const u16_t x,
+			 const u16_t y,
+			 const struct display_buffer_descriptor *desc,
+			 void *buf)
+{
+	struct framebuf_dev_data *data = FRAMEBUF_DATA(dev);
+	u32_t *src = data->buffer;
+	u32_t *dst = buf;
+	u32_t row;
+
+	src += x;
+	src += (y * data->pitch);
+
+	for (row = 0; row < desc->height; ++row) {
+		(void) memcpy(dst, src, desc->width * sizeof(u32_t));
+		src += data->pitch;
+		dst += desc->pitch;
+	}
+
+	return 0;
+}
+
+const struct display_driver_api framebuf_display_api = {
+	.blanking_on = framebuf_blanking_on,
+	.blanking_off = framebuf_blanking_off,
+	.write = framebuf_write,
+	.read = framebuf_read,
+	.get_framebuffer = framebuf_get_framebuffer,
+	.set_brightness = framebuf_set_brightness,
+	.set_contrast = framebuf_set_contrast,
+	.get_capabilities = framebuf_get_capabilities,
+	.set_pixel_format = framebuf_set_pixel_format,
+	.set_orientation = framebuf_set_orientation
+};

include/arch/x86/multiboot.h

@@ -42,6 +42,18 @@ extern struct x86_multiboot_info x86_multiboot_info;
 #define X86_MULTIBOOT_HEADER_MAGIC	0x1BADB002
 #define X86_MULTIBOOT_EAX_MAGIC		0x2BADB002
 
+/*
+ * Typically, we put no flags in the multiboot header, as it exists solely
+ * to reassure the loader that we're a valid binary. The exception to this
+ * is when we want the loader to configure the framebuffer for us.
+ */
+
+#ifdef CONFIG_X86_MULTIBOOT_FRAMEBUF
+#define X86_MULTIBOOT_HEADER_FLAGS	4
+#else
+#define X86_MULTIBOOT_HEADER_FLAGS	0
+#endif
+
 /* The fb_* fields are valid if X86_MULTIBOOT_INFO_FLAGS_FB is set. */
 
 #define X86_MULTIBOOT_INFO_FLAGS_FB	(1 << 12)

include/display/framebuf.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2019 Intel Corp.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_DISPLAY_FRAMEBUF_H_
+#define ZEPHYR_INCLUDE_DISPLAY_FRAMEBUF_H_
+
+#include <display.h>
+
+extern const struct display_driver_api framebuf_display_api;
+
+struct framebuf_dev_data {
+	void			  *buffer;
+	u32_t			  pitch;
+	u16_t			  width;
+	u16_t			  height;
+};
+
+#define FRAMEBUF_DATA(dev) ((struct framebuf_dev_data *) ((dev)->driver_data))
+
+#endif /* ZEPHYR_INCLUDE_DISPLAY_FRAMEBUF_H_ */