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 = drm->dev_private;
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;
100 	struct resource *res;
101 	int ret;
102 
103 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
104 	if (!priv)
105 		return -ENOMEM;
106 	drm->dev_private = priv;
107 
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);
112 
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);
117 	}
118 
119 	ret = of_reserved_mem_device_init(drm->dev);
120 	if (ret) {
121 		dev_err(&pdev->dev,
122 			"failed to initialize reserved mem: %d\n", ret);
123 		return ret;
124 	}
125 
126 	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
127 	if (ret) {
128 		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
129 		return ret;
130 	}
131 
132 	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
133 	if (IS_ERR(priv->rst)) {
134 		dev_err(&pdev->dev,
135 			"missing or invalid reset controller device tree entry");
136 		return PTR_ERR(priv->rst);
137 	}
138 	reset_control_deassert(priv->rst);
139 
140 	priv->clk = devm_clk_get(drm->dev, NULL);
141 	if (IS_ERR(priv->clk)) {
142 		dev_err(&pdev->dev,
143 			"missing or invalid clk device tree entry");
144 		return PTR_ERR(priv->clk);
145 	}
146 	clk_prepare_enable(priv->clk);
147 
148 	/* Sanitize control registers */
149 	writel(0, priv->base + CRT_CTRL1);
150 	writel(0, priv->base + CRT_CTRL2);
151 
152 	aspeed_gfx_setup_mode_config(drm);
153 
154 	ret = drm_vblank_init(drm, 1);
155 	if (ret < 0) {
156 		dev_err(drm->dev, "Failed to initialise vblank\n");
157 		return ret;
158 	}
159 
160 	ret = aspeed_gfx_create_output(drm);
161 	if (ret < 0) {
162 		dev_err(drm->dev, "Failed to create outputs\n");
163 		return ret;
164 	}
165 
166 	ret = aspeed_gfx_create_pipe(drm);
167 	if (ret < 0) {
168 		dev_err(drm->dev, "Cannot setup simple display pipe\n");
169 		return ret;
170 	}
171 
172 	ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
173 			       aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
174 	if (ret < 0) {
175 		dev_err(drm->dev, "Failed to install IRQ handler\n");
176 		return ret;
177 	}
178 
179 	drm_mode_config_reset(drm);
180 
181 	drm_fbdev_generic_setup(drm, 32);
182 
183 	return 0;
184 }
185 
186 static void aspeed_gfx_unload(struct drm_device *drm)
187 {
188 	drm_kms_helper_poll_fini(drm);
189 	drm_mode_config_cleanup(drm);
190 
191 	drm->dev_private = NULL;
192 }
193 
194 DEFINE_DRM_GEM_CMA_FOPS(fops);
195 
196 static struct drm_driver aspeed_gfx_driver = {
197 	.driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
198 	.gem_create_object	= drm_cma_gem_create_object_default_funcs,
199 	.dumb_create		= drm_gem_cma_dumb_create,
200 	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
201 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
202 	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
203 	.gem_prime_mmap		= drm_gem_prime_mmap,
204 	.fops = &fops,
205 	.name = "aspeed-gfx-drm",
206 	.desc = "ASPEED GFX DRM",
207 	.date = "20180319",
208 	.major = 1,
209 	.minor = 0,
210 };
211 
212 static const struct of_device_id aspeed_gfx_match[] = {
213 	{ .compatible = "aspeed,ast2500-gfx" },
214 	{ }
215 };
216 
217 static int aspeed_gfx_probe(struct platform_device *pdev)
218 {
219 	struct drm_device *drm;
220 	int ret;
221 
222 	drm = drm_dev_alloc(&aspeed_gfx_driver, &pdev->dev);
223 	if (IS_ERR(drm))
224 		return PTR_ERR(drm);
225 
226 	ret = aspeed_gfx_load(drm);
227 	if (ret)
228 		goto err_free;
229 
230 	ret = drm_dev_register(drm, 0);
231 	if (ret)
232 		goto err_unload;
233 
234 	return 0;
235 
236 err_unload:
237 	aspeed_gfx_unload(drm);
238 err_free:
239 	drm_dev_put(drm);
240 
241 	return ret;
242 }
243 
244 static int aspeed_gfx_remove(struct platform_device *pdev)
245 {
246 	struct drm_device *drm = platform_get_drvdata(pdev);
247 
248 	drm_dev_unregister(drm);
249 	aspeed_gfx_unload(drm);
250 	drm_dev_put(drm);
251 
252 	return 0;
253 }
254 
255 static struct platform_driver aspeed_gfx_platform_driver = {
256 	.probe		= aspeed_gfx_probe,
257 	.remove		= aspeed_gfx_remove,
258 	.driver = {
259 		.name = "aspeed_gfx",
260 		.of_match_table = aspeed_gfx_match,
261 	},
262 };
263 
264 module_platform_driver(aspeed_gfx_platform_driver);
265 
266 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
267 MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
268 MODULE_LICENSE("GPL");
269