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/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	struct resource *res;
147	int ret;
148
149	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
150	priv->base = devm_ioremap_resource(drm->dev, res);
151	if (IS_ERR(priv->base))
152		return PTR_ERR(priv->base);
153
154	config = device_get_match_data(&pdev->dev);
155	if (!config)
156		return -EINVAL;
157
158	priv->dac_reg = config->dac_reg;
159	priv->int_clr_reg = config->int_clear_reg;
160	priv->vga_scratch_reg = config->vga_scratch_reg;
161	priv->throd_val = config->throd_val;
162	priv->scan_line_max = config->scan_line_max;
163
164	priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
165	if (IS_ERR(priv->scu)) {
166		priv->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
167		if (IS_ERR(priv->scu)) {
168			dev_err(&pdev->dev, "failed to find SCU regmap\n");
169			return PTR_ERR(priv->scu);
170		}
171	}
172
173	ret = of_reserved_mem_device_init(drm->dev);
174	if (ret) {
175		dev_err(&pdev->dev,
176			"failed to initialize reserved mem: %d\n", ret);
177		return ret;
178	}
179
180	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
181	if (ret) {
182		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", ret);
183		return ret;
184	}
185
186	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
187	if (IS_ERR(priv->rst)) {
188		dev_err(&pdev->dev,
189			"missing or invalid reset controller device tree entry");
190		return PTR_ERR(priv->rst);
191	}
192	reset_control_deassert(priv->rst);
193
194	priv->clk = devm_clk_get(drm->dev, NULL);
195	if (IS_ERR(priv->clk)) {
196		dev_err(&pdev->dev,
197			"missing or invalid clk device tree entry");
198		return PTR_ERR(priv->clk);
199	}
200	clk_prepare_enable(priv->clk);
201
202	/* Sanitize control registers */
203	writel(0, priv->base + CRT_CTRL1);
204	writel(0, priv->base + CRT_CTRL2);
205
206	ret = aspeed_gfx_setup_mode_config(drm);
207	if (ret < 0)
208		return ret;
209
210	ret = drm_vblank_init(drm, 1);
211	if (ret < 0) {
212		dev_err(drm->dev, "Failed to initialise vblank\n");
213		return ret;
214	}
215
216	ret = aspeed_gfx_create_output(drm);
217	if (ret < 0) {
218		dev_err(drm->dev, "Failed to create outputs\n");
219		return ret;
220	}
221
222	ret = aspeed_gfx_create_pipe(drm);
223	if (ret < 0) {
224		dev_err(drm->dev, "Cannot setup simple display pipe\n");
225		return ret;
226	}
227
228	ret = devm_request_irq(drm->dev, platform_get_irq(pdev, 0),
229			       aspeed_gfx_irq_handler, 0, "aspeed gfx", drm);
230	if (ret < 0) {
231		dev_err(drm->dev, "Failed to install IRQ handler\n");
232		return ret;
233	}
234
235	drm_mode_config_reset(drm);
236
237	return 0;
238}
239
240static void aspeed_gfx_unload(struct drm_device *drm)
241{
242	drm_kms_helper_poll_fini(drm);
243}
244
245DEFINE_DRM_GEM_DMA_FOPS(fops);
246
247static const struct drm_driver aspeed_gfx_driver = {
248	.driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
249	DRM_GEM_DMA_DRIVER_OPS,
250	.fops = &fops,
251	.name = "aspeed-gfx-drm",
252	.desc = "ASPEED GFX DRM",
253	.date = "20180319",
254	.major = 1,
255	.minor = 0,
256};
257
258static ssize_t dac_mux_store(struct device *dev, struct device_attribute *attr,
259			     const char *buf, size_t count)
260{
261	struct aspeed_gfx *priv = dev_get_drvdata(dev);
262	u32 val;
263	int rc;
264
265	rc = kstrtou32(buf, 0, &val);
266	if (rc)
267		return rc;
268
269	if (val > 3)
270		return -EINVAL;
271
272	rc = regmap_update_bits(priv->scu, priv->dac_reg, 0x30000, val << 16);
273	if (rc < 0)
274		return 0;
275
276	return count;
277}
278
279static ssize_t dac_mux_show(struct device *dev, struct device_attribute *attr, char *buf)
280{
281	struct aspeed_gfx *priv = dev_get_drvdata(dev);
282	u32 reg;
283	int rc;
284
285	rc = regmap_read(priv->scu, priv->dac_reg, &reg);
286	if (rc)
287		return rc;
288
289	return sprintf(buf, "%u\n", (reg >> 16) & 0x3);
290}
291static DEVICE_ATTR_RW(dac_mux);
292
293static ssize_t
294vga_pw_show(struct device *dev, struct device_attribute *attr, char *buf)
295{
296	struct aspeed_gfx *priv = dev_get_drvdata(dev);
297	u32 reg;
298	int rc;
299
300	rc = regmap_read(priv->scu, priv->vga_scratch_reg, &reg);
301	if (rc)
302		return rc;
303
304	return sprintf(buf, "%u\n", reg);
305}
306static DEVICE_ATTR_RO(vga_pw);
307
308static struct attribute *aspeed_sysfs_entries[] = {
309	&dev_attr_vga_pw.attr,
310	&dev_attr_dac_mux.attr,
311	NULL,
312};
313
314static struct attribute_group aspeed_sysfs_attr_group = {
315	.attrs = aspeed_sysfs_entries,
316};
317
318static int aspeed_gfx_probe(struct platform_device *pdev)
319{
320	struct aspeed_gfx *priv;
321	int ret;
322
323	priv = devm_drm_dev_alloc(&pdev->dev, &aspeed_gfx_driver,
324				  struct aspeed_gfx, drm);
325	if (IS_ERR(priv))
326		return PTR_ERR(priv);
327
328	ret = aspeed_gfx_load(&priv->drm);
329	if (ret)
330		return ret;
331
332	platform_set_drvdata(pdev, priv);
333
334	ret = sysfs_create_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
335	if (ret)
336		return ret;
337
338	ret = drm_dev_register(&priv->drm, 0);
339	if (ret)
340		goto err_unload;
341
342	drm_fbdev_dma_setup(&priv->drm, 32);
343	return 0;
344
345err_unload:
346	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
347	aspeed_gfx_unload(&priv->drm);
348
349	return ret;
350}
351
352static void aspeed_gfx_remove(struct platform_device *pdev)
353{
354	struct drm_device *drm = platform_get_drvdata(pdev);
355
356	sysfs_remove_group(&pdev->dev.kobj, &aspeed_sysfs_attr_group);
357	drm_dev_unregister(drm);
358	aspeed_gfx_unload(drm);
359	drm_atomic_helper_shutdown(drm);
360}
361
362static void aspeed_gfx_shutdown(struct platform_device *pdev)
363{
364	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
365}
366
367static struct platform_driver aspeed_gfx_platform_driver = {
368	.probe		= aspeed_gfx_probe,
369	.remove_new	= aspeed_gfx_remove,
370	.shutdown	= aspeed_gfx_shutdown,
371	.driver = {
372		.name = "aspeed_gfx",
373		.of_match_table = aspeed_gfx_match,
374	},
375};
376
377drm_module_platform_driver(aspeed_gfx_platform_driver);
378
379MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
380MODULE_DESCRIPTION("ASPEED BMC DRM/KMS driver");
381MODULE_LICENSE("GPL");