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 Hardware Video Scaler (HVS) is the piece of hardware that does
 13 * translation, scaling, colorspace conversion, and compositing of
 14 * pixels stored in framebuffers into a FIFO of pixels going out to
 15 * the Pixel Valve (CRTC).  It operates at the system clock rate (the
 16 * system audio clock gate, specifically), which is much higher than
 17 * the pixel 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 }
 30static 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
 63void 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
 86int 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 */
133static 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
137static 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);
145	if (ret) {
146		DRM_ERROR("Failed to allocate space for filter kernel: %d\n",
147			  ret);
148		return ret;
149	}
150
151	dst_kernel = hvs->dlist + space->start;
152
153	for (i = 0; i < VC4_KERNEL_DWORDS; i++) {
154		if (i < VC4_LINEAR_PHASE_KERNEL_DWORDS)
155			writel(kernel[i], &dst_kernel[i]);
156		else {
157			writel(kernel[VC4_KERNEL_DWORDS - i - 1],
158			       &dst_kernel[i]);
159		}
160	}
161
162	return 0;
163}
164
165static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
166{
167	struct platform_device *pdev = to_platform_device(dev);
168	struct drm_device *drm = dev_get_drvdata(master);
169	struct vc4_dev *vc4 = drm->dev_private;
170	struct vc4_hvs *hvs = NULL;
171	int ret;
172	u32 dispctrl;
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
215	dispctrl = HVS_READ(SCALER_DISPCTRL);
216
217	dispctrl |= SCALER_DISPCTRL_ENABLE;
218
219	/* Set DSP3 (PV1) to use HVS channel 2, which would otherwise
220	 * be unused.
221	 */
222	dispctrl &= ~SCALER_DISPCTRL_DSP3_MUX_MASK;
223	dispctrl |= VC4_SET_FIELD(2, SCALER_DISPCTRL_DSP3_MUX);
224
225	HVS_WRITE(SCALER_DISPCTRL, dispctrl);
226
227	return 0;
228}
229
230static void vc4_hvs_unbind(struct device *dev, struct device *master,
231			   void *data)
232{
233	struct drm_device *drm = dev_get_drvdata(master);
234	struct vc4_dev *vc4 = drm->dev_private;
235
236	if (vc4->hvs->mitchell_netravali_filter.allocated)
237		drm_mm_remove_node(&vc4->hvs->mitchell_netravali_filter);
238
239	drm_mm_takedown(&vc4->hvs->dlist_mm);
240	drm_mm_takedown(&vc4->hvs->lbm_mm);
241
242	vc4->hvs = NULL;
243}
244
245static const struct component_ops vc4_hvs_ops = {
246	.bind   = vc4_hvs_bind,
247	.unbind = vc4_hvs_unbind,
248};
249
250static int vc4_hvs_dev_probe(struct platform_device *pdev)
251{
252	return component_add(&pdev->dev, &vc4_hvs_ops);
253}
254
255static int vc4_hvs_dev_remove(struct platform_device *pdev)
256{
257	component_del(&pdev->dev, &vc4_hvs_ops);
258	return 0;
259}
260
261static const struct of_device_id vc4_hvs_dt_match[] = {
262	{ .compatible = "brcm,bcm2835-hvs" },
263	{}
264};
265
266struct platform_driver vc4_hvs_driver = {
267	.probe = vc4_hvs_dev_probe,
268	.remove = vc4_hvs_dev_remove,
269	.driver = {
270		.name = "vc4_hvs",
271		.of_match_table = vc4_hvs_dt_match,
272	},
273};