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