xref: /openbmc/linux/drivers/gpu/drm/vc4/vc4_hvs.c (revision f3539c12)
1 /*
2  * Copyright (C) 2015 Broadcom
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 /**
10  * DOC: VC4 HVS module.
11  *
12  * The HVS is the piece of hardware that does translation, scaling,
13  * colorspace conversion, and compositing of pixels stored in
14  * framebuffers into a FIFO of pixels going out to the Pixel Valve
15  * (CRTC).  It operates at the system clock rate (the system audio
16  * clock gate, specifically), which is much higher than the pixel
17  * clock rate.
18  *
19  * There is a single global HVS, with multiple output FIFOs that can
20  * be consumed by the PVs.  This file just manages the resources for
21  * the HVS, while the vc4_crtc.c code actually drives HVS setup for
22  * each CRTC.
23  */
24 
25 #include "linux/component.h"
26 #include "vc4_drv.h"
27 #include "vc4_regs.h"
28 
29 #define HVS_REG(reg) { reg, #reg }
30 static const struct {
31 	u32 reg;
32 	const char *name;
33 } hvs_regs[] = {
34 	HVS_REG(SCALER_DISPCTRL),
35 	HVS_REG(SCALER_DISPSTAT),
36 	HVS_REG(SCALER_DISPID),
37 	HVS_REG(SCALER_DISPECTRL),
38 	HVS_REG(SCALER_DISPPROF),
39 	HVS_REG(SCALER_DISPDITHER),
40 	HVS_REG(SCALER_DISPEOLN),
41 	HVS_REG(SCALER_DISPLIST0),
42 	HVS_REG(SCALER_DISPLIST1),
43 	HVS_REG(SCALER_DISPLIST2),
44 	HVS_REG(SCALER_DISPLSTAT),
45 	HVS_REG(SCALER_DISPLACT0),
46 	HVS_REG(SCALER_DISPLACT1),
47 	HVS_REG(SCALER_DISPLACT2),
48 	HVS_REG(SCALER_DISPCTRL0),
49 	HVS_REG(SCALER_DISPBKGND0),
50 	HVS_REG(SCALER_DISPSTAT0),
51 	HVS_REG(SCALER_DISPBASE0),
52 	HVS_REG(SCALER_DISPCTRL1),
53 	HVS_REG(SCALER_DISPBKGND1),
54 	HVS_REG(SCALER_DISPSTAT1),
55 	HVS_REG(SCALER_DISPBASE1),
56 	HVS_REG(SCALER_DISPCTRL2),
57 	HVS_REG(SCALER_DISPBKGND2),
58 	HVS_REG(SCALER_DISPSTAT2),
59 	HVS_REG(SCALER_DISPBASE2),
60 	HVS_REG(SCALER_DISPALPHA2),
61 };
62 
63 void vc4_hvs_dump_state(struct drm_device *dev)
64 {
65 	struct vc4_dev *vc4 = to_vc4_dev(dev);
66 	int i;
67 
68 	for (i = 0; i < ARRAY_SIZE(hvs_regs); i++) {
69 		DRM_INFO("0x%04x (%s): 0x%08x\n",
70 			 hvs_regs[i].reg, hvs_regs[i].name,
71 			 HVS_READ(hvs_regs[i].reg));
72 	}
73 
74 	DRM_INFO("HVS ctx:\n");
75 	for (i = 0; i < 64; i += 4) {
76 		DRM_INFO("0x%08x (%s): 0x%08x 0x%08x 0x%08x 0x%08x\n",
77 			 i * 4, i < HVS_BOOTLOADER_DLIST_END ? "B" : "D",
78 			 readl((u32 __iomem *)vc4->hvs->dlist + i + 0),
79 			 readl((u32 __iomem *)vc4->hvs->dlist + i + 1),
80 			 readl((u32 __iomem *)vc4->hvs->dlist + i + 2),
81 			 readl((u32 __iomem *)vc4->hvs->dlist + i + 3));
82 	}
83 }
84 
85 #ifdef CONFIG_DEBUG_FS
86 int vc4_hvs_debugfs_regs(struct seq_file *m, void *unused)
87 {
88 	struct drm_info_node *node = (struct drm_info_node *)m->private;
89 	struct drm_device *dev = node->minor->dev;
90 	struct vc4_dev *vc4 = to_vc4_dev(dev);
91 	int i;
92 
93 	for (i = 0; i < ARRAY_SIZE(hvs_regs); i++) {
94 		seq_printf(m, "%s (0x%04x): 0x%08x\n",
95 			   hvs_regs[i].name, hvs_regs[i].reg,
96 			   HVS_READ(hvs_regs[i].reg));
97 	}
98 
99 	return 0;
100 }
101 #endif
102 
103 /* The filter kernel is composed of dwords each containing 3 9-bit
104  * signed integers packed next to each other.
105  */
106 #define VC4_INT_TO_COEFF(coeff) (coeff & 0x1ff)
107 #define VC4_PPF_FILTER_WORD(c0, c1, c2)				\
108 	((((c0) & 0x1ff) << 0) |				\
109 	 (((c1) & 0x1ff) << 9) |				\
110 	 (((c2) & 0x1ff) << 18))
111 
112 /* The whole filter kernel is arranged as the coefficients 0-16 going
113  * up, then a pad, then 17-31 going down and reversed within the
114  * dwords.  This means that a linear phase kernel (where it's
115  * symmetrical at the boundary between 15 and 16) has the last 5
116  * dwords matching the first 5, but reversed.
117  */
118 #define VC4_LINEAR_PHASE_KERNEL(c0, c1, c2, c3, c4, c5, c6, c7, c8,	\
119 				c9, c10, c11, c12, c13, c14, c15)	\
120 	{VC4_PPF_FILTER_WORD(c0, c1, c2),				\
121 	 VC4_PPF_FILTER_WORD(c3, c4, c5),				\
122 	 VC4_PPF_FILTER_WORD(c6, c7, c8),				\
123 	 VC4_PPF_FILTER_WORD(c9, c10, c11),				\
124 	 VC4_PPF_FILTER_WORD(c12, c13, c14),				\
125 	 VC4_PPF_FILTER_WORD(c15, c15, 0)}
126 
127 #define VC4_LINEAR_PHASE_KERNEL_DWORDS 6
128 #define VC4_KERNEL_DWORDS (VC4_LINEAR_PHASE_KERNEL_DWORDS * 2 - 1)
129 
130 /* Recommended B=1/3, C=1/3 filter choice from Mitchell/Netravali.
131  * http://www.cs.utexas.edu/~fussell/courses/cs384g/lectures/mitchell/Mitchell.pdf
132  */
133 static const u32 mitchell_netravali_1_3_1_3_kernel[] =
134 	VC4_LINEAR_PHASE_KERNEL(0, -2, -6, -8, -10, -8, -3, 2, 18,
135 				50, 82, 119, 155, 187, 213, 227);
136 
137 static int vc4_hvs_upload_linear_kernel(struct vc4_hvs *hvs,
138 					struct drm_mm_node *space,
139 					const u32 *kernel)
140 {
141 	int ret, i;
142 	u32 __iomem *dst_kernel;
143 
144 	ret = drm_mm_insert_node(&hvs->dlist_mm, space, VC4_KERNEL_DWORDS, 1,
145 				 0);
146 	if (ret) {
147 		DRM_ERROR("Failed to allocate space for filter kernel: %d\n",
148 			  ret);
149 		return ret;
150 	}
151 
152 	dst_kernel = hvs->dlist + space->start;
153 
154 	for (i = 0; i < VC4_KERNEL_DWORDS; i++) {
155 		if (i < VC4_LINEAR_PHASE_KERNEL_DWORDS)
156 			writel(kernel[i], &dst_kernel[i]);
157 		else {
158 			writel(kernel[VC4_KERNEL_DWORDS - i - 1],
159 			       &dst_kernel[i]);
160 		}
161 	}
162 
163 	return 0;
164 }
165 
166 static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
167 {
168 	struct platform_device *pdev = to_platform_device(dev);
169 	struct drm_device *drm = dev_get_drvdata(master);
170 	struct vc4_dev *vc4 = drm->dev_private;
171 	struct vc4_hvs *hvs = NULL;
172 	int ret;
173 
174 	hvs = devm_kzalloc(&pdev->dev, sizeof(*hvs), GFP_KERNEL);
175 	if (!hvs)
176 		return -ENOMEM;
177 
178 	hvs->pdev = pdev;
179 
180 	hvs->regs = vc4_ioremap_regs(pdev, 0);
181 	if (IS_ERR(hvs->regs))
182 		return PTR_ERR(hvs->regs);
183 
184 	hvs->dlist = hvs->regs + SCALER_DLIST_START;
185 
186 	spin_lock_init(&hvs->mm_lock);
187 
188 	/* Set up the HVS display list memory manager.  We never
189 	 * overwrite the setup from the bootloader (just 128b out of
190 	 * our 16K), since we don't want to scramble the screen when
191 	 * transitioning from the firmware's boot setup to runtime.
192 	 */
193 	drm_mm_init(&hvs->dlist_mm,
194 		    HVS_BOOTLOADER_DLIST_END,
195 		    (SCALER_DLIST_SIZE >> 2) - HVS_BOOTLOADER_DLIST_END);
196 
197 	/* Set up the HVS LBM memory manager.  We could have some more
198 	 * complicated data structure that allowed reuse of LBM areas
199 	 * between planes when they don't overlap on the screen, but
200 	 * for now we just allocate globally.
201 	 */
202 	drm_mm_init(&hvs->lbm_mm, 0, 96 * 1024);
203 
204 	/* Upload filter kernels.  We only have the one for now, so we
205 	 * keep it around for the lifetime of the driver.
206 	 */
207 	ret = vc4_hvs_upload_linear_kernel(hvs,
208 					   &hvs->mitchell_netravali_filter,
209 					   mitchell_netravali_1_3_1_3_kernel);
210 	if (ret)
211 		return ret;
212 
213 	vc4->hvs = hvs;
214 	return 0;
215 }
216 
217 static void vc4_hvs_unbind(struct device *dev, struct device *master,
218 			   void *data)
219 {
220 	struct drm_device *drm = dev_get_drvdata(master);
221 	struct vc4_dev *vc4 = drm->dev_private;
222 
223 	if (vc4->hvs->mitchell_netravali_filter.allocated)
224 		drm_mm_remove_node(&vc4->hvs->mitchell_netravali_filter);
225 
226 	drm_mm_takedown(&vc4->hvs->dlist_mm);
227 	drm_mm_takedown(&vc4->hvs->lbm_mm);
228 
229 	vc4->hvs = NULL;
230 }
231 
232 static const struct component_ops vc4_hvs_ops = {
233 	.bind   = vc4_hvs_bind,
234 	.unbind = vc4_hvs_unbind,
235 };
236 
237 static int vc4_hvs_dev_probe(struct platform_device *pdev)
238 {
239 	return component_add(&pdev->dev, &vc4_hvs_ops);
240 }
241 
242 static int vc4_hvs_dev_remove(struct platform_device *pdev)
243 {
244 	component_del(&pdev->dev, &vc4_hvs_ops);
245 	return 0;
246 }
247 
248 static const struct of_device_id vc4_hvs_dt_match[] = {
249 	{ .compatible = "brcm,bcm2835-hvs" },
250 	{}
251 };
252 
253 struct platform_driver vc4_hvs_driver = {
254 	.probe = vc4_hvs_dev_probe,
255 	.remove = vc4_hvs_dev_remove,
256 	.driver = {
257 		.name = "vc4_hvs",
258 		.of_match_table = vc4_hvs_dt_match,
259 	},
260 };
261