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 void aspeed_gfx_setup_mode_config(struct drm_device *drm)
67 {
68 	drm_mode_config_init(drm);
69 
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;
75 }
76 
77 static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
78 {
79 	struct drm_device *drm = data;
80 	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
81 	u32 reg;
82 
83 	reg = readl(priv->base + CRT_CTRL1);
84 
85 	if (reg & CRT_CTRL_VERTICAL_INTR_STS) {
86 		drm_crtc_handle_vblank(&priv->pipe.crtc);
87 		writel(reg, priv->base + CRT_CTRL1);
88 		return IRQ_HANDLED;
89 	}
90 
91 	return IRQ_NONE;
92 }
93 
94 
95 
96 static int aspeed_gfx_load(struct drm_device *drm)
97 {
98 	struct platform_device *pdev = to_platform_device(drm->dev);
99 	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
100 	struct resource *res;
101 	int ret;
102 
103 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
104 	priv->base = devm_ioremap_resource(drm->dev, res);
105 	if (IS_ERR(priv->base))
106 		return PTR_ERR(priv->base);
107 
108 	priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
109 	if (IS_ERR(priv->scu)) {
110 		dev_err(&pdev->dev, "failed to find SCU regmap\n");
111 		return PTR_ERR(priv->scu);
112 	}
113 
114 	ret = of_reserved_mem_device_init(drm->dev);
115 	if (ret) {
116 		dev_err(&pdev->dev,
117 			"failed to initialize reserved mem: %d\n", ret);
118 		return ret;
119 	}
120 
121 	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
122 	if (ret) {
123 		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
124 		return ret;
125 	}
126 
127 	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
128 	if (IS_ERR(priv->rst)) {
129 		dev_err(&pdev->dev,
130 			"missing or invalid reset controller device tree entry");
131 		return PTR_ERR(priv->rst);
132 	}
133 	reset_control_deassert(priv->rst);
134 
135 	priv->clk = devm_clk_get(drm->dev, NULL);
136 	if (IS_ERR(priv->clk)) {
137 		dev_err(&pdev->dev,
138 			"missing or invalid clk device tree entry");
139 		return PTR_ERR(priv->clk);
140 	}
141 	clk_prepare_enable(priv->clk);
142 
143 	/* Sanitize control registers */
144 	writel(0, priv->base + CRT_CTRL1);
145 	writel(0, priv->base + CRT_CTRL2);
146 
147 	aspeed_gfx_setup_mode_config(drm);
148 
149 	ret = drm_vblank_init(drm, 1);
150 	if (ret < 0) {
151 		dev_err(drm->dev, "Failed to initialise vblank\n");
152 		return ret;
153 	}
154 
155 	ret = aspeed_gfx_create_output(drm);
156 	if (ret < 0) {
157 		dev_err(drm->dev, "Failed to create outputs\n");
158 		return ret;
159 	}
160 
161 	ret = aspeed_gfx_create_pipe(drm);
162 	if (ret < 0) {
163 		dev_err(drm->dev, "Cannot setup simple display pipe\n");
164 		return ret;
165 	}
166 
167 	ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
168 			       aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
169 	if (ret < 0) {
170 		dev_err(drm->dev, "Failed to install IRQ handler\n");
171 		return ret;
172 	}
173 
174 	drm_mode_config_reset(drm);
175 
176 	drm_fbdev_generic_setup(drm, 32);
177 
178 	return 0;
179 }
180 
181 static void aspeed_gfx_unload(struct drm_device *drm)
182 {
183 	drm_kms_helper_poll_fini(drm);
184 	drm_mode_config_cleanup(drm);
185 }
186 
187 DEFINE_DRM_GEM_CMA_FOPS(fops);
188 
189 static struct drm_driver aspeed_gfx_driver = {
190 	.driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
191 	.gem_create_object	= drm_cma_gem_create_object_default_funcs,
192 	.dumb_create		= drm_gem_cma_dumb_create,
193 	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
194 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
195 	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
196 	.gem_prime_mmap		= drm_gem_prime_mmap,
197 	.fops = &fops,
198 	.name = "aspeed-gfx-drm",
199 	.desc = "ASPEED GFX DRM",
200 	.date = "20180319",
201 	.major = 1,
202 	.minor = 0,
203 };
204 
205 static const struct of_device_id aspeed_gfx_match[] = {
206 	{ .compatible = "aspeed,ast2500-gfx" },
207 	{ }
208 };
209 
210 static int aspeed_gfx_probe(struct platform_device *pdev)
211 {
212 	struct aspeed_gfx *priv;
213 	int ret;
214 
215 	priv = devm_drm_dev_alloc(&pdev->dev, &aspeed_gfx_driver,
216 				  struct aspeed_gfx, drm);
217 	if (IS_ERR(priv))
218 		return PTR_ERR(priv);
219 
220 	ret = aspeed_gfx_load(&priv->drm);
221 	if (ret)
222 		return ret;
223 
224 	ret = drm_dev_register(&priv->drm, 0);
225 	if (ret)
226 		goto err_unload;
227 
228 	return 0;
229 
230 err_unload:
231 	aspeed_gfx_unload(&priv->drm);
232 
233 	return ret;
234 }
235 
236 static int aspeed_gfx_remove(struct platform_device *pdev)
237 {
238 	struct drm_device *drm = platform_get_drvdata(pdev);
239 
240 	drm_dev_unregister(drm);
241 	aspeed_gfx_unload(drm);
242 
243 	return 0;
244 }
245 
246 static struct platform_driver aspeed_gfx_platform_driver = {
247 	.probe		= aspeed_gfx_probe,
248 	.remove		= aspeed_gfx_remove,
249 	.driver = {
250 		.name = "aspeed_gfx",
251 		.of_match_table = aspeed_gfx_match,
252 	},
253 };
254 
255 module_platform_driver(aspeed_gfx_platform_driver);
256 
257 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
258 MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
259 MODULE_LICENSE("GPL");
260