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_device.h>
11 #include <linux/of_reserved_mem.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 #include <linux/reset.h>
15 
16 #include <drm/drm_atomic_helper.h>
17 #include <drm/drm_device.h>
18 #include <drm/drm_fbdev_dma.h>
19 #include <drm/drm_gem_dma_helper.h>
20 #include <drm/drm_gem_framebuffer_helper.h>
21 #include <drm/drm_module.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 struct aspeed_gfx_config {
61 	u32 dac_reg;		/* DAC register in SCU */
62 	u32 int_clear_reg;	/* Interrupt clear register */
63 	u32 vga_scratch_reg;	/* VGA scratch register in SCU */
64 	u32 throd_val;		/* Default Threshold Seting */
65 	u32 scan_line_max;	/* Max memory size of one scan line */
66 };
67 
68 static const struct aspeed_gfx_config ast2400_config = {
69 	.dac_reg = 0x2c,
70 	.int_clear_reg = 0x60,
71 	.vga_scratch_reg = 0x50,
72 	.throd_val = CRT_THROD_LOW(0x1e) | CRT_THROD_HIGH(0x12),
73 	.scan_line_max = 64,
74 };
75 
76 static const struct aspeed_gfx_config ast2500_config = {
77 	.dac_reg = 0x2c,
78 	.int_clear_reg = 0x60,
79 	.vga_scratch_reg = 0x50,
80 	.throd_val = CRT_THROD_LOW(0x24) | CRT_THROD_HIGH(0x3c),
81 	.scan_line_max = 128,
82 };
83 
84 static const struct aspeed_gfx_config ast2600_config = {
85 	.dac_reg = 0xc0,
86 	.int_clear_reg = 0x68,
87 	.vga_scratch_reg = 0x50,
88 	.throd_val = CRT_THROD_LOW(0x50) | CRT_THROD_HIGH(0x70),
89 	.scan_line_max = 128,
90 };
91 
92 static const struct of_device_id aspeed_gfx_match[] = {
93 	{ .compatible = "aspeed,ast2400-gfx", .data = &ast2400_config },
94 	{ .compatible = "aspeed,ast2500-gfx", .data = &ast2500_config },
95 	{ .compatible = "aspeed,ast2600-gfx", .data = &ast2600_config },
96 	{ },
97 };
98 MODULE_DEVICE_TABLE(of, aspeed_gfx_match);
99 
100 static const struct drm_mode_config_funcs aspeed_gfx_mode_config_funcs = {
101 	.fb_create		= drm_gem_fb_create,
102 	.atomic_check		= drm_atomic_helper_check,
103 	.atomic_commit		= drm_atomic_helper_commit,
104 };
105 
106 static int aspeed_gfx_setup_mode_config(struct drm_device *drm)
107 {
108 	int ret;
109 
110 	ret = drmm_mode_config_init(drm);
111 	if (ret)
112 		return ret;
113 
114 	drm->mode_config.min_width = 0;
115 	drm->mode_config.min_height = 0;
116 	drm->mode_config.max_width = 800;
117 	drm->mode_config.max_height = 600;
118 	drm->mode_config.funcs = &aspeed_gfx_mode_config_funcs;
119 
120 	return ret;
121 }
122 
123 static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
124 {
125 	struct drm_device *drm = data;
126 	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
127 	u32 reg;
128 
129 	reg = readl(priv->base + CRT_CTRL1);
130 
131 	if (reg & CRT_CTRL_VERTICAL_INTR_STS) {
132 		drm_crtc_handle_vblank(&priv->pipe.crtc);
133 		writel(reg, priv->base + priv->int_clr_reg);
134 		return IRQ_HANDLED;
135 	}
136 
137 	return IRQ_NONE;
138 }
139 
140 static int aspeed_gfx_load(struct drm_device *drm)
141 {
142 	struct platform_device *pdev = to_platform_device(drm->dev);
143 	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
144 	struct device_node *np = pdev->dev.of_node;
145 	const struct aspeed_gfx_config *config;
146 	const struct of_device_id *match;
147 	struct resource *res;
148 	int ret;
149 
150 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
151 	priv->base = devm_ioremap_resource(drm->dev, res);
152 	if (IS_ERR(priv->base))
153 		return PTR_ERR(priv->base);
154 
155 	match = of_match_device(aspeed_gfx_match, &pdev->dev);
156 	if (!match)
157 		return -EINVAL;
158 	config = match->data;
159 
160 	priv->dac_reg = config->dac_reg;
161 	priv->int_clr_reg = config->int_clear_reg;
162 	priv->vga_scratch_reg = config->vga_scratch_reg;
163 	priv->throd_val = config->throd_val;
164 	priv->scan_line_max = config->scan_line_max;
165 
166 	priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
167 	if (IS_ERR(priv->scu)) {
168 		priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
169 		if (IS_ERR(priv->scu)) {
170 			dev_err(&pdev->dev, "failed to find SCU regmap\n");
171 			return PTR_ERR(priv->scu);
172 		}
173 	}
174 
175 	ret = of_reserved_mem_device_init(drm->dev);
176 	if (ret) {
177 		dev_err(&pdev->dev,
178 			"failed to initialize reserved mem: %d\n", ret);
179 		return ret;
180 	}
181 
182 	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
183 	if (ret) {
184 		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
185 		return ret;
186 	}
187 
188 	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
189 	if (IS_ERR(priv->rst)) {
190 		dev_err(&pdev->dev,
191 			"missing or invalid reset controller device tree entry");
192 		return PTR_ERR(priv->rst);
193 	}
194 	reset_control_deassert(priv->rst);
195 
196 	priv->clk = devm_clk_get(drm->dev, NULL);
197 	if (IS_ERR(priv->clk)) {
198 		dev_err(&pdev->dev,
199 			"missing or invalid clk device tree entry");
200 		return PTR_ERR(priv->clk);
201 	}
202 	clk_prepare_enable(priv->clk);
203 
204 	/* Sanitize control registers */
205 	writel(0, priv->base + CRT_CTRL1);
206 	writel(0, priv->base + CRT_CTRL2);
207 
208 	ret = aspeed_gfx_setup_mode_config(drm);
209 	if (ret < 0)
210 		return ret;
211 
212 	ret = drm_vblank_init(drm, 1);
213 	if (ret < 0) {
214 		dev_err(drm->dev, "Failed to initialise vblank\n");
215 		return ret;
216 	}
217 
218 	ret = aspeed_gfx_create_output(drm);
219 	if (ret < 0) {
220 		dev_err(drm->dev, "Failed to create outputs\n");
221 		return ret;
222 	}
223 
224 	ret = aspeed_gfx_create_pipe(drm);
225 	if (ret < 0) {
226 		dev_err(drm->dev, "Cannot setup simple display pipe\n");
227 		return ret;
228 	}
229 
230 	ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
231 			       aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
232 	if (ret < 0) {
233 		dev_err(drm->dev, "Failed to install IRQ handler\n");
234 		return ret;
235 	}
236 
237 	drm_mode_config_reset(drm);
238 
239 	return 0;
240 }
241 
242 static void aspeed_gfx_unload(struct drm_device *drm)
243 {
244 	drm_kms_helper_poll_fini(drm);
245 }
246 
247 DEFINE_DRM_GEM_DMA_FOPS(fops);
248 
249 static const struct drm_driver aspeed_gfx_driver = {
250 	.driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
251 	DRM_GEM_DMA_DRIVER_OPS,
252 	.fops = &fops,
253 	.name = "aspeed-gfx-drm",
254 	.desc = "ASPEED GFX DRM",
255 	.date = "20180319",
256 	.major = 1,
257 	.minor = 0,
258 };
259 
260 static ssize_t dac_mux_store(struct device *dev, struct device_attribute *attr,
261 			     const char *buf, size_t count)
262 {
263 	struct aspeed_gfx *priv = dev_get_drvdata(dev);
264 	u32 val;
265 	int rc;
266 
267 	rc = kstrtou32(buf, 0, &val);
268 	if (rc)
269 		return rc;
270 
271 	if (val > 3)
272 		return -EINVAL;
273 
274 	rc = regmap_update_bits(priv->scu, priv->dac_reg, 0x30000, val << 16);
275 	if (rc < 0)
276 		return 0;
277 
278 	return count;
279 }
280 
281 static ssize_t dac_mux_show(struct device *dev, struct device_attribute *attr, char *buf)
282 {
283 	struct aspeed_gfx *priv = dev_get_drvdata(dev);
284 	u32 reg;
285 	int rc;
286 
287 	rc = regmap_read(priv->scu, priv->dac_reg, &reg);
288 	if (rc)
289 		return rc;
290 
291 	return sprintf(buf, "%u\n", (reg >> 16) & 0x3);
292 }
293 static DEVICE_ATTR_RW(dac_mux);
294 
295 static ssize_t
296 vga_pw_show(struct device *dev, struct device_attribute *attr, char *buf)
297 {
298 	struct aspeed_gfx *priv = dev_get_drvdata(dev);
299 	u32 reg;
300 	int rc;
301 
302 	rc = regmap_read(priv->scu, priv->vga_scratch_reg, &reg);
303 	if (rc)
304 		return rc;
305 
306 	return sprintf(buf, "%u\n", reg);
307 }
308 static DEVICE_ATTR_RO(vga_pw);
309 
310 static struct attribute *aspeed_sysfs_entries[] = {
311 	&dev_attr_vga_pw.attr,
312 	&dev_attr_dac_mux.attr,
313 	NULL,
314 };
315 
316 static struct attribute_group aspeed_sysfs_attr_group = {
317 	.attrs = aspeed_sysfs_entries,
318 };
319 
320 static int aspeed_gfx_probe(struct platform_device *pdev)
321 {
322 	struct aspeed_gfx *priv;
323 	int ret;
324 
325 	priv = devm_drm_dev_alloc(&pdev->dev, &aspeed_gfx_driver,
326 				  struct aspeed_gfx, drm);
327 	if (IS_ERR(priv))
328 		return PTR_ERR(priv);
329 
330 	ret = aspeed_gfx_load(&priv->drm);
331 	if (ret)
332 		return ret;
333 
334 	platform_set_drvdata(pdev, priv);
335 
336 	ret = sysfs_create_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
337 	if (ret)
338 		return ret;
339 
340 	ret = drm_dev_register(&priv->drm, 0);
341 	if (ret)
342 		goto err_unload;
343 
344 	drm_fbdev_dma_setup(&priv->drm, 32);
345 	return 0;
346 
347 err_unload:
348 	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
349 	aspeed_gfx_unload(&priv->drm);
350 
351 	return ret;
352 }
353 
354 static int aspeed_gfx_remove(struct platform_device *pdev)
355 {
356 	struct drm_device *drm = platform_get_drvdata(pdev);
357 
358 	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
359 	drm_dev_unregister(drm);
360 	aspeed_gfx_unload(drm);
361 
362 	return 0;
363 }
364 
365 static struct platform_driver aspeed_gfx_platform_driver = {
366 	.probe		= aspeed_gfx_probe,
367 	.remove		= aspeed_gfx_remove,
368 	.driver = {
369 		.name = "aspeed_gfx",
370 		.of_match_table = aspeed_gfx_match,
371 	},
372 };
373 
374 drm_module_platform_driver(aspeed_gfx_platform_driver);
375 
376 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
377 MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
378 MODULE_LICENSE("GPL");
379