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
aspeed_gfx_setup_mode_config(struct drm_device * drm)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
aspeed_gfx_irq_handler(int irq,void * data)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
aspeed_gfx_load(struct drm_device * drm)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
aspeed_gfx_unload(struct drm_device * drm)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
aspeed_gfx_probe(struct platform_device * pdev)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
aspeed_gfx_remove(struct platform_device * pdev)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