1 // SPDX-License-Identifier: GPL-2.0+
2 // Copyright 2018 IBM Corporation
3 
4 #include <linux/clk.h>
5 #include <linux/dma-mapping.h>
6 #include <linux/irq.h>
7 #include <linux/mfd/syscon.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/of_reserved_mem.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 #include <linux/reset.h>
14 
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>
26 
27 #include "aspeed_gfx.h"
28 
29 /**
30  * DOC: ASPEED GFX Driver
31  *
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.
36  *
37  * The AST2500 supports a total of 3 output paths:
38  *
39  *   1. VGA output, the output target can choose either or both to the DAC
40  *   or DVO interface.
41  *
42  *   2. Graphics CRT output, the output target can choose either or both to
43  *   the DAC or DVO interface.
44  *
45  *   3. Video input from DVO, the video input can be used for video engine
46  *   capture or DAC display output.
47  *
48  * Output options are selected in SCU2C.
49  *
50  * The "VGA mode" device is the PCI attached controller. The "Graphics CRT"
51  * is the ARM's internal display controller.
52  *
53  * The driver only supports a simple configuration consisting of a 40MHz
54  * pixel clock, fixed by hardware limitations, and the VGA output path.
55  *
56  * The driver was written with the 'AST2500 Software Programming Guide' v17,
57  * which is available under NDA from ASPEED.
58  */
59 
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,
64 };
65 
66 static int aspeed_gfx_setup_mode_config(struct drm_device *drm)
67 {
68 	int ret;
69 
70 	ret = drmm_mode_config_init(drm);
71 	if (ret)
72 		return ret;
73 
74 	drm->mode_config.min_width = 0;
75 	drm->mode_config.min_height = 0;
76 	drm->mode_config.max_width = 800;
77 	drm->mode_config.max_height = 600;
78 	drm->mode_config.funcs = &aspeed_gfx_mode_config_funcs;
79 
80 	return ret;
81 }
82 
83 static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
84 {
85 	struct drm_device *drm = data;
86 	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
87 	u32 reg;
88 
89 	reg = readl(priv->base + CRT_CTRL1);
90 
91 	if (reg & CRT_CTRL_VERTICAL_INTR_STS) {
92 		drm_crtc_handle_vblank(&priv->pipe.crtc);
93 		writel(reg, priv->base + CRT_CTRL1);
94 		return IRQ_HANDLED;
95 	}
96 
97 	return IRQ_NONE;
98 }
99 
100 
101 
102 static int aspeed_gfx_load(struct drm_device *drm)
103 {
104 	struct platform_device *pdev = to_platform_device(drm->dev);
105 	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
106 	struct resource *res;
107 	int ret;
108 
109 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
110 	priv->base = devm_ioremap_resource(drm->dev, res);
111 	if (IS_ERR(priv->base))
112 		return PTR_ERR(priv->base);
113 
114 	priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
115 	if (IS_ERR(priv->scu)) {
116 		dev_err(&pdev->dev, "failed to find SCU regmap\n");
117 		return PTR_ERR(priv->scu);
118 	}
119 
120 	ret = of_reserved_mem_device_init(drm->dev);
121 	if (ret) {
122 		dev_err(&pdev->dev,
123 			"failed to initialize reserved mem: %d\n", ret);
124 		return ret;
125 	}
126 
127 	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
128 	if (ret) {
129 		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
130 		return ret;
131 	}
132 
133 	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
134 	if (IS_ERR(priv->rst)) {
135 		dev_err(&pdev->dev,
136 			"missing or invalid reset controller device tree entry");
137 		return PTR_ERR(priv->rst);
138 	}
139 	reset_control_deassert(priv->rst);
140 
141 	priv->clk = devm_clk_get(drm->dev, NULL);
142 	if (IS_ERR(priv->clk)) {
143 		dev_err(&pdev->dev,
144 			"missing or invalid clk device tree entry");
145 		return PTR_ERR(priv->clk);
146 	}
147 	clk_prepare_enable(priv->clk);
148 
149 	/* Sanitize control registers */
150 	writel(0, priv->base + CRT_CTRL1);
151 	writel(0, priv->base + CRT_CTRL2);
152 
153 	ret = aspeed_gfx_setup_mode_config(drm);
154 	if (ret < 0)
155 		return ret;
156 
157 	ret = drm_vblank_init(drm, 1);
158 	if (ret < 0) {
159 		dev_err(drm->dev, "Failed to initialise vblank\n");
160 		return ret;
161 	}
162 
163 	ret = aspeed_gfx_create_output(drm);
164 	if (ret < 0) {
165 		dev_err(drm->dev, "Failed to create outputs\n");
166 		return ret;
167 	}
168 
169 	ret = aspeed_gfx_create_pipe(drm);
170 	if (ret < 0) {
171 		dev_err(drm->dev, "Cannot setup simple display pipe\n");
172 		return ret;
173 	}
174 
175 	ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
176 			       aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
177 	if (ret < 0) {
178 		dev_err(drm->dev, "Failed to install IRQ handler\n");
179 		return ret;
180 	}
181 
182 	drm_mode_config_reset(drm);
183 
184 	return 0;
185 }
186 
187 static void aspeed_gfx_unload(struct drm_device *drm)
188 {
189 	drm_kms_helper_poll_fini(drm);
190 }
191 
192 DEFINE_DRM_GEM_CMA_FOPS(fops);
193 
194 static struct drm_driver aspeed_gfx_driver = {
195 	.driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
196 	.gem_create_object	= drm_gem_cma_create_object_default_funcs,
197 	.dumb_create		= drm_gem_cma_dumb_create,
198 	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
199 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
200 	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
201 	.gem_prime_mmap		= drm_gem_prime_mmap,
202 	.fops = &fops,
203 	.name = "aspeed-gfx-drm",
204 	.desc = "ASPEED GFX DRM",
205 	.date = "20180319",
206 	.major = 1,
207 	.minor = 0,
208 };
209 
210 static const struct of_device_id aspeed_gfx_match[] = {
211 	{ .compatible = "aspeed,ast2500-gfx" },
212 	{ }
213 };
214 
215 static int aspeed_gfx_probe(struct platform_device *pdev)
216 {
217 	struct aspeed_gfx *priv;
218 	int ret;
219 
220 	priv = devm_drm_dev_alloc(&pdev->dev, &aspeed_gfx_driver,
221 				  struct aspeed_gfx, drm);
222 	if (IS_ERR(priv))
223 		return PTR_ERR(priv);
224 
225 	ret = aspeed_gfx_load(&priv->drm);
226 	if (ret)
227 		return ret;
228 
229 	ret = drm_dev_register(&priv->drm, 0);
230 	if (ret)
231 		goto err_unload;
232 
233 	drm_fbdev_generic_setup(&priv->drm, 32);
234 	return 0;
235 
236 err_unload:
237 	aspeed_gfx_unload(&priv->drm);
238 
239 	return ret;
240 }
241 
242 static int aspeed_gfx_remove(struct platform_device *pdev)
243 {
244 	struct drm_device *drm = platform_get_drvdata(pdev);
245 
246 	drm_dev_unregister(drm);
247 	aspeed_gfx_unload(drm);
248 
249 	return 0;
250 }
251 
252 static struct platform_driver aspeed_gfx_platform_driver = {
253 	.probe		= aspeed_gfx_probe,
254 	.remove		= aspeed_gfx_remove,
255 	.driver = {
256 		.name = "aspeed_gfx",
257 		.of_match_table = aspeed_gfx_match,
258 	},
259 };
260 
261 module_platform_driver(aspeed_gfx_platform_driver);
262 
263 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
264 MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
265 MODULE_LICENSE("GPL");
266