1 // SPDX-License-Identifier: GPL-2.0+
2 // Copyright 2018 IBM Corporation
5 #include <linux/dma-mapping.h>
7 #include <linux/mfd/syscon.h>
8 #include <linux/module.h>
10 #include <linux/of_reserved_mem.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 #include <linux/reset.h>
15 #include <drm/drm_atomic_helper.h>
16 #include <drm/drm_crtc_helper.h>
17 #include <drm/drm_device.h>
18 #include <drm/drm_fb_cma_helper.h>
19 #include <drm/drm_fb_helper.h>
20 #include <drm/drm_gem_cma_helper.h>
21 #include <drm/drm_gem_framebuffer_helper.h>
22 #include <drm/drm_probe_helper.h>
23 #include <drm/drm_simple_kms_helper.h>
24 #include <drm/drm_vblank.h>
25 #include <drm/drm_drv.h>
27 #include "aspeed_gfx.h"
30 * DOC: ASPEED GFX Driver
32 * This driver is for the ASPEED BMC SoC's 'GFX' display hardware, also called
33 * the 'SOC Display Controller' in the datasheet. This driver runs on the ARM
34 * based BMC systems, unlike the ast driver which runs on a host CPU and is for
35 * a PCIe graphics device.
37 * The AST2500 supports a total of 3 output paths:
39 * 1. VGA output, the output target can choose either or both to the DAC
42 * 2. Graphics CRT output, the output target can choose either or both to
43 * the DAC or DVO interface.
45 * 3. Video input from DVO, the video input can be used for video engine
46 * capture or DAC display output.
48 * Output options are selected in SCU2C.
50 * The "VGA mode" device is the PCI attached controller. The "Graphics CRT"
51 * is the ARM's internal display controller.
53 * The driver only supports a simple configuration consisting of a 40MHz
54 * pixel clock, fixed by hardware limitations, and the VGA output path.
56 * The driver was written with the 'AST2500 Software Programming Guide' v17,
57 * which is available under NDA from ASPEED.
60 static const struct drm_mode_config_funcs aspeed_gfx_mode_config_funcs = {
61 .fb_create = drm_gem_fb_create,
62 .atomic_check = drm_atomic_helper_check,
63 .atomic_commit = drm_atomic_helper_commit,
66 static void aspeed_gfx_setup_mode_config(struct drm_device *drm)
68 drm_mode_config_init(drm);
70 drm->mode_config.min_width = 0;
71 drm->mode_config.min_height = 0;
72 drm->mode_config.max_width = 800;
73 drm->mode_config.max_height = 600;
74 drm->mode_config.funcs = &aspeed_gfx_mode_config_funcs;
77 static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
79 struct drm_device *drm = data;
80 struct aspeed_gfx *priv = drm->dev_private;
83 reg = readl(priv->base + CRT_CTRL1);
85 if (reg & CRT_CTRL_VERTICAL_INTR_STS) {
86 drm_crtc_handle_vblank(&priv->pipe.crtc);
87 writel(reg, priv->base + CRT_CTRL1);
96 static int aspeed_gfx_load(struct drm_device *drm)
98 struct platform_device *pdev = to_platform_device(drm->dev);
99 struct aspeed_gfx *priv;
100 struct resource *res;
103 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
106 drm->dev_private = priv;
108 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
109 priv->base = devm_ioremap_resource(drm->dev, res);
110 if (IS_ERR(priv->base))
111 return PTR_ERR(priv->base);
113 priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
114 if (IS_ERR(priv->scu)) {
115 dev_err(&pdev->dev, "failed to find SCU regmap\n");
116 return PTR_ERR(priv->scu);
119 ret = of_reserved_mem_device_init(drm->dev);
122 "failed to initialize reserved mem: %d\n", ret);
126 ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
128 dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
132 priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
133 if (IS_ERR(priv->rst)) {
135 "missing or invalid reset controller device tree entry");
136 return PTR_ERR(priv->rst);
138 reset_control_deassert(priv->rst);
140 priv->clk = devm_clk_get(drm->dev, NULL);
141 if (IS_ERR(priv->clk)) {
143 "missing or invalid clk device tree entry");
144 return PTR_ERR(priv->clk);
146 clk_prepare_enable(priv->clk);
148 /* Sanitize control registers */
149 writel(0, priv->base + CRT_CTRL1);
150 writel(0, priv->base + CRT_CTRL2);
152 aspeed_gfx_setup_mode_config(drm);
154 ret = drm_vblank_init(drm, 1);
156 dev_err(drm->dev, "Failed to initialise vblank\n");
160 ret = aspeed_gfx_create_output(drm);
162 dev_err(drm->dev, "Failed to create outputs\n");
166 ret = aspeed_gfx_create_pipe(drm);
168 dev_err(drm->dev, "Cannot setup simple display pipe\n");
172 ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
173 aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
175 dev_err(drm->dev, "Failed to install IRQ handler\n");
179 drm_mode_config_reset(drm);
181 drm_fbdev_generic_setup(drm, 32);
186 static void aspeed_gfx_unload(struct drm_device *drm)
188 drm_kms_helper_poll_fini(drm);
189 drm_mode_config_cleanup(drm);
191 drm->dev_private = NULL;
194 DEFINE_DRM_GEM_CMA_FOPS(fops);
196 static struct drm_driver aspeed_gfx_driver = {
197 .driver_features = DRIVER_GEM | DRIVER_MODESET |
198 DRIVER_PRIME | DRIVER_ATOMIC,
199 .gem_create_object = drm_cma_gem_create_object_default_funcs,
200 .dumb_create = drm_gem_cma_dumb_create,
201 .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
202 .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
203 .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
204 .gem_prime_mmap = drm_gem_prime_mmap,
206 .name = "aspeed-gfx-drm",
207 .desc = "ASPEED GFX DRM",
213 static const struct of_device_id aspeed_gfx_match[] = {
214 { .compatible = "aspeed,ast2500-gfx" },
218 static int aspeed_gfx_probe(struct platform_device *pdev)
220 struct drm_device *drm;
223 drm = drm_dev_alloc(&aspeed_gfx_driver, &pdev->dev);
227 ret = aspeed_gfx_load(drm);
231 ret = drm_dev_register(drm, 0);
238 aspeed_gfx_unload(drm);
245 static int aspeed_gfx_remove(struct platform_device *pdev)
247 struct drm_device *drm = platform_get_drvdata(pdev);
249 drm_dev_unregister(drm);
250 aspeed_gfx_unload(drm);
256 static struct platform_driver aspeed_gfx_platform_driver = {
257 .probe = aspeed_gfx_probe,
258 .remove = aspeed_gfx_remove,
260 .name = "aspeed_gfx",
261 .of_match_table = aspeed_gfx_match,
265 module_platform_driver(aspeed_gfx_platform_driver);
267 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
268 MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
269 MODULE_LICENSE("GPL");