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
60struct 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
68static 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
76static 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
84static 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
92static 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};
98MODULE_DEVICE_TABLE(of, aspeed_gfx_match);
99
100static 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
106static 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
123static 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
140static 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
242static void aspeed_gfx_unload(struct drm_device *drm)
243{
244	drm_kms_helper_poll_fini(drm);
245}
246
247DEFINE_DRM_GEM_DMA_FOPS(fops);
248
249static 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
260static 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
281static 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}
293static DEVICE_ATTR_RW(dac_mux);
294
295static ssize_t
296vga_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}
308static DEVICE_ATTR_RO(vga_pw);
309
310static struct attribute *aspeed_sysfs_entries[] = {
311	&dev_attr_vga_pw.attr,
312	&dev_attr_dac_mux.attr,
313	NULL,
314};
315
316static struct attribute_group aspeed_sysfs_attr_group = {
317	.attrs = aspeed_sysfs_entries,
318};
319
320static 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
347err_unload:
348	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
349	aspeed_gfx_unload(&priv->drm);
350
351	return ret;
352}
353
354static void 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	drm_atomic_helper_shutdown(drm);
362}
363
364static void aspeed_gfx_shutdown(struct platform_device *pdev)
365{
366	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
367}
368
369static struct platform_driver aspeed_gfx_platform_driver = {
370	.probe		= aspeed_gfx_probe,
371	.remove_new	= aspeed_gfx_remove,
372	.shutdown	= aspeed_gfx_shutdown,
373	.driver = {
374		.name = "aspeed_gfx",
375		.of_match_table = aspeed_gfx_match,
376	},
377};
378
379drm_module_platform_driver(aspeed_gfx_platform_driver);
380
381MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
382MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
383MODULE_LICENSE("GPL");
384