aspeed_gfx_drv.c

  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/mod_devicetable.h>
 10#include <linux/of_reserved_mem.h>
 11#include <linux/platform_device.h>
 12#include <linux/property.h>
 13#include <linux/regmap.h>
 14#include <linux/reset.h>
 15
 16#include <drm/clients/drm_client_setup.h>
 17#include <drm/drm_atomic_helper.h>
 18#include <drm/drm_device.h>
 19#include <drm/drm_fbdev_dma.h>
 20#include <drm/drm_gem_dma_helper.h>
 21#include <drm/drm_gem_framebuffer_helper.h>
 22#include <drm/drm_module.h>
 23#include <drm/drm_probe_helper.h>
 24#include <drm/drm_simple_kms_helper.h>
 25#include <drm/drm_vblank.h>
 26#include <drm/drm_drv.h>
 27
 28#include "aspeed_gfx.h"
 29
 30/**
 31 * DOC: ASPEED GFX Driver
 32 *
 33 * This driver is for the ASPEED BMC SoC's 'GFX' display hardware, also called
 34 * the 'SOC Display Controller' in the datasheet. This driver runs on the ARM
 35 * based BMC systems, unlike the ast driver which runs on a host CPU and is for
 36 * a PCIe graphics device.
 37 *
 38 * The AST2500 supports a total of 3 output paths:
 39 *
 40 *   1. VGA output, the output target can choose either or both to the DAC
 41 *   or DVO interface.
 42 *
 43 *   2. Graphics CRT output, the output target can choose either or both to
 44 *   the DAC or DVO interface.
 45 *
 46 *   3. Video input from DVO, the video input can be used for video engine
 47 *   capture or DAC display output.
 48 *
 49 * Output options are selected in SCU2C.
 50 *
 51 * The "VGA mode" device is the PCI attached controller. The "Graphics CRT"
 52 * is the ARM's internal display controller.
 53 *
 54 * The driver only supports a simple configuration consisting of a 40MHz
 55 * pixel clock, fixed by hardware limitations, and the VGA output path.
 56 *
 57 * The driver was written with the 'AST2500 Software Programming Guide' v17,
 58 * which is available under NDA from ASPEED.
 59 */
 60
 61struct aspeed_gfx_config {
 62	u32 dac_reg;		/* DAC register in SCU */
 63	u32 int_clear_reg;	/* Interrupt clear register */
 64	u32 vga_scratch_reg;	/* VGA scratch register in SCU */
 65	u32 throd_val;		/* Default Threshold Seting */
 66	u32 scan_line_max;	/* Max memory size of one scan line */
 67};
 68
 69static const struct aspeed_gfx_config ast2400_config = {
 70	.dac_reg = 0x2c,
 71	.int_clear_reg = 0x60,
 72	.vga_scratch_reg = 0x50,
 73	.throd_val = CRT_THROD_LOW(0x1e) | CRT_THROD_HIGH(0x12),
 74	.scan_line_max = 64,
 75};
 76
 77static const struct aspeed_gfx_config ast2500_config = {
 78	.dac_reg = 0x2c,
 79	.int_clear_reg = 0x60,
 80	.vga_scratch_reg = 0x50,
 81	.throd_val = CRT_THROD_LOW(0x24) | CRT_THROD_HIGH(0x3c),
 82	.scan_line_max = 128,
 83};
 84
 85static const struct aspeed_gfx_config ast2600_config = {
 86	.dac_reg = 0xc0,
 87	.int_clear_reg = 0x68,
 88	.vga_scratch_reg = 0x50,
 89	.throd_val = CRT_THROD_LOW(0x50) | CRT_THROD_HIGH(0x70),
 90	.scan_line_max = 128,
 91};
 92
 93static const struct of_device_id aspeed_gfx_match[] = {
 94	{ .compatible = "aspeed,ast2400-gfx", .data = &ast2400_config },
 95	{ .compatible = "aspeed,ast2500-gfx", .data = &ast2500_config },
 96	{ .compatible = "aspeed,ast2600-gfx", .data = &ast2600_config },
 97	{ },
 98};
 99MODULE_DEVICE_TABLE(of, aspeed_gfx_match);
100
101static const struct drm_mode_config_funcs aspeed_gfx_mode_config_funcs = {
102	.fb_create		= drm_gem_fb_create,
103	.atomic_check		= drm_atomic_helper_check,
104	.atomic_commit		= drm_atomic_helper_commit,
105};
106
107static int aspeed_gfx_setup_mode_config(struct drm_device *drm)
108{
109	int ret;
110
111	ret = drmm_mode_config_init(drm);
112	if (ret)
113		return ret;
114
115	drm->mode_config.min_width = 0;
116	drm->mode_config.min_height = 0;
117	drm->mode_config.max_width = 800;
118	drm->mode_config.max_height = 600;
119	drm->mode_config.funcs = &aspeed_gfx_mode_config_funcs;
120
121	return ret;
122}
123
124static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
125{
126	struct drm_device *drm = data;
127	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
128	u32 reg;
129
130	reg = readl(priv->base + CRT_CTRL1);
131
132	if (reg & CRT_CTRL_VERTICAL_INTR_STS) {
133		drm_crtc_handle_vblank(&priv->pipe.crtc);
134		writel(reg, priv->base + priv->int_clr_reg);
135		return IRQ_HANDLED;
136	}
137
138	return IRQ_NONE;
139}
140
141static int aspeed_gfx_load(struct drm_device *drm)
142{
143	struct platform_device *pdev = to_platform_device(drm->dev);
144	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
145	struct device_node *np = pdev->dev.of_node;
146	const struct aspeed_gfx_config *config;
147	int ret;
148
149	priv->base = devm_platform_ioremap_resource(pdev, 0);
150	if (IS_ERR(priv->base))
151		return PTR_ERR(priv->base);
152
153	config = device_get_match_data(&pdev->dev);
154	if (!config)
155		return -EINVAL;
156
157	priv->dac_reg = config->dac_reg;
158	priv->int_clr_reg = config->int_clear_reg;
159	priv->vga_scratch_reg = config->vga_scratch_reg;
160	priv->throd_val = config->throd_val;
161	priv->scan_line_max = config->scan_line_max;
162
163	priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
164	if (IS_ERR(priv->scu)) {
165		priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
166		if (IS_ERR(priv->scu)) {
167			dev_err(&pdev->dev, "failed to find SCU regmap\n");
168			return PTR_ERR(priv->scu);
169		}
170	}
171
172	ret = of_reserved_mem_device_init(drm->dev);
173	if (ret) {
174		dev_err(&pdev->dev,
175			"failed to initialize reserved mem: %d\n", ret);
176		return ret;
177	}
178
179	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
180	if (ret) {
181		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
182		return ret;
183	}
184
185	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
186	if (IS_ERR(priv->rst)) {
187		dev_err(&pdev->dev,
188			"missing or invalid reset controller device tree entry");
189		return PTR_ERR(priv->rst);
190	}
191	reset_control_deassert(priv->rst);
192
193	priv->clk = devm_clk_get(drm->dev, NULL);
194	if (IS_ERR(priv->clk)) {
195		dev_err(&pdev->dev,
196			"missing or invalid clk device tree entry");
197		return PTR_ERR(priv->clk);
198	}
199	clk_prepare_enable(priv->clk);
200
201	/* Sanitize control registers */
202	writel(0, priv->base + CRT_CTRL1);
203	writel(0, priv->base + CRT_CTRL2);
204
205	ret = aspeed_gfx_setup_mode_config(drm);
206	if (ret < 0)
207		return ret;
208
209	ret = drm_vblank_init(drm, 1);
210	if (ret < 0) {
211		dev_err(drm->dev, "Failed to initialise vblank\n");
212		return ret;
213	}
214
215	ret = aspeed_gfx_create_output(drm);
216	if (ret < 0) {
217		dev_err(drm->dev, "Failed to create outputs\n");
218		return ret;
219	}
220
221	ret = aspeed_gfx_create_pipe(drm);
222	if (ret < 0) {
223		dev_err(drm->dev, "Cannot setup simple display pipe\n");
224		return ret;
225	}
226
227	ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
228			       aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
229	if (ret < 0) {
230		dev_err(drm->dev, "Failed to install IRQ handler\n");
231		return ret;
232	}
233
234	drm_mode_config_reset(drm);
235
236	return 0;
237}
238
239static void aspeed_gfx_unload(struct drm_device *drm)
240{
241	drm_kms_helper_poll_fini(drm);
242}
243
244DEFINE_DRM_GEM_DMA_FOPS(fops);
245
246static const struct drm_driver aspeed_gfx_driver = {
247	.driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
248	DRM_GEM_DMA_DRIVER_OPS,
249	DRM_FBDEV_DMA_DRIVER_OPS,
250	.fops = &fops,
251	.name = "aspeed-gfx-drm",
252	.desc = "ASPEED GFX DRM",
253	.major = 1,
254	.minor = 0,
255};
256
257static ssize_t dac_mux_store(struct device *dev, struct device_attribute *attr,
258			     const char *buf, size_t count)
259{
260	struct aspeed_gfx *priv = dev_get_drvdata(dev);
261	u32 val;
262	int rc;
263
264	rc = kstrtou32(buf, 0, &val);
265	if (rc)
266		return rc;
267
268	if (val > 3)
269		return -EINVAL;
270
271	rc = regmap_update_bits(priv->scu, priv->dac_reg, 0x30000, val << 16);
272	if (rc < 0)
273		return 0;
274
275	return count;
276}
277
278static ssize_t dac_mux_show(struct device *dev, struct device_attribute *attr, char *buf)
279{
280	struct aspeed_gfx *priv = dev_get_drvdata(dev);
281	u32 reg;
282	int rc;
283
284	rc = regmap_read(priv->scu, priv->dac_reg, &reg);
285	if (rc)
286		return rc;
287
288	return sprintf(buf, "%u\n", (reg >> 16) & 0x3);
289}
290static DEVICE_ATTR_RW(dac_mux);
291
292static ssize_t
293vga_pw_show(struct device *dev, struct device_attribute *attr, char *buf)
294{
295	struct aspeed_gfx *priv = dev_get_drvdata(dev);
296	u32 reg;
297	int rc;
298
299	rc = regmap_read(priv->scu, priv->vga_scratch_reg, &reg);
300	if (rc)
301		return rc;
302
303	return sprintf(buf, "%u\n", reg);
304}
305static DEVICE_ATTR_RO(vga_pw);
306
307static struct attribute *aspeed_sysfs_entries[] = {
308	&dev_attr_vga_pw.attr,
309	&dev_attr_dac_mux.attr,
310	NULL,
311};
312
313static struct attribute_group aspeed_sysfs_attr_group = {
314	.attrs = aspeed_sysfs_entries,
315};
316
317static int aspeed_gfx_probe(struct platform_device *pdev)
318{
319	struct aspeed_gfx *priv;
320	int ret;
321
322	priv = devm_drm_dev_alloc(&pdev->dev, &aspeed_gfx_driver,
323				  struct aspeed_gfx, drm);
324	if (IS_ERR(priv))
325		return PTR_ERR(priv);
326
327	ret = aspeed_gfx_load(&priv->drm);
328	if (ret)
329		return ret;
330
331	platform_set_drvdata(pdev, priv);
332
333	ret = sysfs_create_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
334	if (ret)
335		return ret;
336
337	ret = drm_dev_register(&priv->drm, 0);
338	if (ret)
339		goto err_unload;
340
341	drm_client_setup(&priv->drm, NULL);
342	return 0;
343
344err_unload:
345	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
346	aspeed_gfx_unload(&priv->drm);
347
348	return ret;
349}
350
351static void aspeed_gfx_remove(struct platform_device *pdev)
352{
353	struct drm_device *drm = platform_get_drvdata(pdev);
354
355	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
356	drm_dev_unregister(drm);
357	aspeed_gfx_unload(drm);
358	drm_atomic_helper_shutdown(drm);
359}
360
361static void aspeed_gfx_shutdown(struct platform_device *pdev)
362{
363	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
364}
365
366static struct platform_driver aspeed_gfx_platform_driver = {
367	.probe		= aspeed_gfx_probe,
368	.remove		= aspeed_gfx_remove,
369	.shutdown	= aspeed_gfx_shutdown,
370	.driver = {
371		.name = "aspeed_gfx",
372		.of_match_table = aspeed_gfx_match,
373	},
374};
375
376drm_module_platform_driver(aspeed_gfx_platform_driver);
377
378MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
379MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
380MODULE_LICENSE("GPL");