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_reserved_mem.h>
10 #include <linux/platform_device.h>
11 #include <linux/property.h>
12 #include <linux/regmap.h>
13 #include <linux/reset.h>
14
15 #include <drm/clients/drm_client_setup.h>
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
aspeed_gfx_setup_mode_config(struct drm_device * drm)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
aspeed_gfx_irq_handler(int irq,void * data)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
aspeed_gfx_load(struct drm_device * drm)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 int ret;
147
148 priv->base = devm_platform_ioremap_resource(pdev, 0);
149 if (IS_ERR(priv->base))
150 return PTR_ERR(priv->base);
151
152 config = device_get_match_data(&pdev->dev);
153 if (!config)
154 return -EINVAL;
155
156 priv->dac_reg = config->dac_reg;
157 priv->int_clr_reg = config->int_clear_reg;
158 priv->vga_scratch_reg = config->vga_scratch_reg;
159 priv->throd_val = config->throd_val;
160 priv->scan_line_max = config->scan_line_max;
161
162 priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
163 if (IS_ERR(priv->scu)) {
164 priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
165 if (IS_ERR(priv->scu)) {
166 dev_err(&pdev->dev, "failed to find SCU regmap\n");
167 return PTR_ERR(priv->scu);
168 }
169 }
170
171 ret = of_reserved_mem_device_init(drm->dev);
172 if (ret) {
173 dev_err(&pdev->dev,
174 "failed to initialize reserved mem: %d\n", ret);
175 return ret;
176 }
177
178 ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
179 if (ret) {
180 dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
181 return ret;
182 }
183
184 priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
185 if (IS_ERR(priv->rst)) {
186 dev_err(&pdev->dev,
187 "missing or invalid reset controller device tree entry");
188 return PTR_ERR(priv->rst);
189 }
190 reset_control_deassert(priv->rst);
191
192 priv->clk = devm_clk_get(drm->dev, NULL);
193 if (IS_ERR(priv->clk)) {
194 dev_err(&pdev->dev,
195 "missing or invalid clk device tree entry");
196 return PTR_ERR(priv->clk);
197 }
198 clk_prepare_enable(priv->clk);
199
200 /* Sanitize control registers */
201 writel(0, priv->base + CRT_CTRL1);
202 writel(0, priv->base + CRT_CTRL2);
203
204 ret = aspeed_gfx_setup_mode_config(drm);
205 if (ret < 0)
206 return ret;
207
208 ret = drm_vblank_init(drm, 1);
209 if (ret < 0) {
210 dev_err(drm->dev, "Failed to initialise vblank\n");
211 return ret;
212 }
213
214 ret = aspeed_gfx_create_output(drm);
215 if (ret < 0) {
216 dev_err(drm->dev, "Failed to create outputs\n");
217 return ret;
218 }
219
220 ret = aspeed_gfx_create_pipe(drm);
221 if (ret < 0) {
222 dev_err(drm->dev, "Cannot setup simple display pipe\n");
223 return ret;
224 }
225
226 ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
227 aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
228 if (ret < 0) {
229 dev_err(drm->dev, "Failed to install IRQ handler\n");
230 return ret;
231 }
232
233 drm_mode_config_reset(drm);
234
235 return 0;
236 }
237
aspeed_gfx_unload(struct drm_device * drm)238 static void aspeed_gfx_unload(struct drm_device *drm)
239 {
240 drm_kms_helper_poll_fini(drm);
241 }
242
243 DEFINE_DRM_GEM_DMA_FOPS(fops);
244
245 static const struct drm_driver aspeed_gfx_driver = {
246 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
247 DRM_GEM_DMA_DRIVER_OPS,
248 DRM_FBDEV_DMA_DRIVER_OPS,
249 .fops = &fops,
250 .name = "aspeed-gfx-drm",
251 .desc = "ASPEED GFX DRM",
252 .major = 1,
253 .minor = 0,
254 };
255
dac_mux_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)256 static ssize_t dac_mux_store(struct device *dev, struct device_attribute *attr,
257 const char *buf, size_t count)
258 {
259 struct aspeed_gfx *priv = dev_get_drvdata(dev);
260 u32 val;
261 int rc;
262
263 rc = kstrtou32(buf, 0, &val);
264 if (rc)
265 return rc;
266
267 if (val > 3)
268 return -EINVAL;
269
270 rc = regmap_update_bits(priv->scu, priv->dac_reg, 0x30000, val << 16);
271 if (rc < 0)
272 return 0;
273
274 return count;
275 }
276
dac_mux_show(struct device * dev,struct device_attribute * attr,char * buf)277 static ssize_t dac_mux_show(struct device *dev, struct device_attribute *attr, char *buf)
278 {
279 struct aspeed_gfx *priv = dev_get_drvdata(dev);
280 u32 reg;
281 int rc;
282
283 rc = regmap_read(priv->scu, priv->dac_reg, ®);
284 if (rc)
285 return rc;
286
287 return sprintf(buf, "%u\n", (reg >> 16) & 0x3);
288 }
289 static DEVICE_ATTR_RW(dac_mux);
290
291 static ssize_t
vga_pw_show(struct device * dev,struct device_attribute * attr,char * buf)292 vga_pw_show(struct device *dev, struct device_attribute *attr, char *buf)
293 {
294 struct aspeed_gfx *priv = dev_get_drvdata(dev);
295 u32 reg;
296 int rc;
297
298 rc = regmap_read(priv->scu, priv->vga_scratch_reg, ®);
299 if (rc)
300 return rc;
301
302 return sprintf(buf, "%u\n", reg);
303 }
304 static DEVICE_ATTR_RO(vga_pw);
305
306 static struct attribute *aspeed_sysfs_entries[] = {
307 &dev_attr_vga_pw.attr,
308 &dev_attr_dac_mux.attr,
309 NULL,
310 };
311
312 static struct attribute_group aspeed_sysfs_attr_group = {
313 .attrs = aspeed_sysfs_entries,
314 };
315
aspeed_gfx_probe(struct platform_device * pdev)316 static int aspeed_gfx_probe(struct platform_device *pdev)
317 {
318 struct aspeed_gfx *priv;
319 int ret;
320
321 priv = devm_drm_dev_alloc(&pdev->dev, &aspeed_gfx_driver,
322 struct aspeed_gfx, drm);
323 if (IS_ERR(priv))
324 return PTR_ERR(priv);
325
326 ret = aspeed_gfx_load(&priv->drm);
327 if (ret)
328 return ret;
329
330 platform_set_drvdata(pdev, priv);
331
332 ret = sysfs_create_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
333 if (ret)
334 return ret;
335
336 ret = drm_dev_register(&priv->drm, 0);
337 if (ret)
338 goto err_unload;
339
340 drm_client_setup(&priv->drm, NULL);
341 return 0;
342
343 err_unload:
344 sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
345 aspeed_gfx_unload(&priv->drm);
346
347 return ret;
348 }
349
aspeed_gfx_remove(struct platform_device * pdev)350 static void aspeed_gfx_remove(struct platform_device *pdev)
351 {
352 struct drm_device *drm = platform_get_drvdata(pdev);
353
354 sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
355 drm_dev_unregister(drm);
356 aspeed_gfx_unload(drm);
357 drm_atomic_helper_shutdown(drm);
358 }
359
aspeed_gfx_shutdown(struct platform_device * pdev)360 static void aspeed_gfx_shutdown(struct platform_device *pdev)
361 {
362 drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
363 }
364
365 static struct platform_driver aspeed_gfx_platform_driver = {
366 .probe = aspeed_gfx_probe,
367 .remove = aspeed_gfx_remove,
368 .shutdown = aspeed_gfx_shutdown,
369 .driver = {
370 .name = "aspeed_gfx",
371 .of_match_table = aspeed_gfx_match,
372 },
373 };
374
375 drm_module_platform_driver(aspeed_gfx_platform_driver);
376
377 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
378 MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
379 MODULE_LICENSE("GPL");
380