xref: /openbmc/linux/drivers/bus/da8xx-mstpri.c (revision 82e6fdd6) 
1 /*
2  * TI da8xx master peripheral priority driver
3  *
4  * Copyright (C) 2016 BayLibre SAS
5  *
6  * Author:
7  *   Bartosz Golaszewski <bgolaszewski@baylibre.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/io.h>
18 #include <linux/regmap.h>
19 
20 /*
21  * REVISIT: Linux doesn't have a good framework for the kind of performance
22  * knobs this driver controls. We can't use device tree properties as it deals
23  * with hardware configuration rather than description. We also don't want to
24  * commit to maintaining some random sysfs attributes.
25  *
26  * For now we just hardcode the register values for the boards that need
27  * some changes (as is the case for the LCD controller on da850-lcdk - the
28  * first board we support here). When linux gets an appropriate framework,
29  * we'll easily convert the driver to it.
30  */
31 
32 #define DA8XX_MSTPRI0_OFFSET		0
33 #define DA8XX_MSTPRI1_OFFSET		4
34 #define DA8XX_MSTPRI2_OFFSET		8
35 
36 enum {
37 	DA8XX_MSTPRI_ARM_I = 0,
38 	DA8XX_MSTPRI_ARM_D,
39 	DA8XX_MSTPRI_UPP,
40 	DA8XX_MSTPRI_SATA,
41 	DA8XX_MSTPRI_PRU0,
42 	DA8XX_MSTPRI_PRU1,
43 	DA8XX_MSTPRI_EDMA30TC0,
44 	DA8XX_MSTPRI_EDMA30TC1,
45 	DA8XX_MSTPRI_EDMA31TC0,
46 	DA8XX_MSTPRI_VPIF_DMA_0,
47 	DA8XX_MSTPRI_VPIF_DMA_1,
48 	DA8XX_MSTPRI_EMAC,
49 	DA8XX_MSTPRI_USB0CFG,
50 	DA8XX_MSTPRI_USB0CDMA,
51 	DA8XX_MSTPRI_UHPI,
52 	DA8XX_MSTPRI_USB1,
53 	DA8XX_MSTPRI_LCDC,
54 };
55 
56 struct da8xx_mstpri_descr {
57 	int reg;
58 	int shift;
59 	int mask;
60 };
61 
62 static const struct da8xx_mstpri_descr da8xx_mstpri_priority_list[] = {
63 	[DA8XX_MSTPRI_ARM_I] = {
64 		.reg = DA8XX_MSTPRI0_OFFSET,
65 		.shift = 0,
66 		.mask = 0x0000000f,
67 	},
68 	[DA8XX_MSTPRI_ARM_D] = {
69 		.reg = DA8XX_MSTPRI0_OFFSET,
70 		.shift = 4,
71 		.mask = 0x000000f0,
72 	},
73 	[DA8XX_MSTPRI_UPP] = {
74 		.reg = DA8XX_MSTPRI0_OFFSET,
75 		.shift = 16,
76 		.mask = 0x000f0000,
77 	},
78 	[DA8XX_MSTPRI_SATA] = {
79 		.reg = DA8XX_MSTPRI0_OFFSET,
80 		.shift = 20,
81 		.mask = 0x00f00000,
82 	},
83 	[DA8XX_MSTPRI_PRU0] = {
84 		.reg = DA8XX_MSTPRI1_OFFSET,
85 		.shift = 0,
86 		.mask = 0x0000000f,
87 	},
88 	[DA8XX_MSTPRI_PRU1] = {
89 		.reg = DA8XX_MSTPRI1_OFFSET,
90 		.shift = 4,
91 		.mask = 0x000000f0,
92 	},
93 	[DA8XX_MSTPRI_EDMA30TC0] = {
94 		.reg = DA8XX_MSTPRI1_OFFSET,
95 		.shift = 8,
96 		.mask = 0x00000f00,
97 	},
98 	[DA8XX_MSTPRI_EDMA30TC1] = {
99 		.reg = DA8XX_MSTPRI1_OFFSET,
100 		.shift = 12,
101 		.mask = 0x0000f000,
102 	},
103 	[DA8XX_MSTPRI_EDMA31TC0] = {
104 		.reg = DA8XX_MSTPRI1_OFFSET,
105 		.shift = 16,
106 		.mask = 0x000f0000,
107 	},
108 	[DA8XX_MSTPRI_VPIF_DMA_0] = {
109 		.reg = DA8XX_MSTPRI1_OFFSET,
110 		.shift = 24,
111 		.mask = 0x0f000000,
112 	},
113 	[DA8XX_MSTPRI_VPIF_DMA_1] = {
114 		.reg = DA8XX_MSTPRI1_OFFSET,
115 		.shift = 28,
116 		.mask = 0xf0000000,
117 	},
118 	[DA8XX_MSTPRI_EMAC] = {
119 		.reg = DA8XX_MSTPRI2_OFFSET,
120 		.shift = 0,
121 		.mask = 0x0000000f,
122 	},
123 	[DA8XX_MSTPRI_USB0CFG] = {
124 		.reg = DA8XX_MSTPRI2_OFFSET,
125 		.shift = 8,
126 		.mask = 0x00000f00,
127 	},
128 	[DA8XX_MSTPRI_USB0CDMA] = {
129 		.reg = DA8XX_MSTPRI2_OFFSET,
130 		.shift = 12,
131 		.mask = 0x0000f000,
132 	},
133 	[DA8XX_MSTPRI_UHPI] = {
134 		.reg = DA8XX_MSTPRI2_OFFSET,
135 		.shift = 20,
136 		.mask = 0x00f00000,
137 	},
138 	[DA8XX_MSTPRI_USB1] = {
139 		.reg = DA8XX_MSTPRI2_OFFSET,
140 		.shift = 24,
141 		.mask = 0x0f000000,
142 	},
143 	[DA8XX_MSTPRI_LCDC] = {
144 		.reg = DA8XX_MSTPRI2_OFFSET,
145 		.shift = 28,
146 		.mask = 0xf0000000,
147 	},
148 };
149 
150 struct da8xx_mstpri_priority {
151 	int which;
152 	u32 val;
153 };
154 
155 struct da8xx_mstpri_board_priorities {
156 	const char *board;
157 	const struct da8xx_mstpri_priority *priorities;
158 	size_t numprio;
159 };
160 
161 /*
162  * Default memory settings of da850 do not meet the throughput/latency
163  * requirements of tilcdc. This results in the image displayed being
164  * incorrect and the following warning being displayed by the LCDC
165  * drm driver:
166  *
167  *   tilcdc da8xx_lcdc.0: tilcdc_crtc_irq(0x00000020): FIFO underfow
168  */
169 static const struct da8xx_mstpri_priority da850_lcdk_priorities[] = {
170 	{
171 		.which = DA8XX_MSTPRI_LCDC,
172 		.val = 0,
173 	},
174 	{
175 		.which = DA8XX_MSTPRI_EDMA30TC1,
176 		.val = 0,
177 	},
178 	{
179 		.which = DA8XX_MSTPRI_EDMA30TC0,
180 		.val = 1,
181 	},
182 };
183 
184 static const struct da8xx_mstpri_board_priorities da8xx_mstpri_board_confs[] = {
185 	{
186 		.board = "ti,da850-lcdk",
187 		.priorities = da850_lcdk_priorities,
188 		.numprio = ARRAY_SIZE(da850_lcdk_priorities),
189 	},
190 };
191 
192 static const struct da8xx_mstpri_board_priorities *
193 da8xx_mstpri_get_board_prio(void)
194 {
195 	const struct da8xx_mstpri_board_priorities *board_prio;
196 	int i;
197 
198 	for (i = 0; i < ARRAY_SIZE(da8xx_mstpri_board_confs); i++) {
199 		board_prio = &da8xx_mstpri_board_confs[i];
200 
201 		if (of_machine_is_compatible(board_prio->board))
202 			return board_prio;
203 	}
204 
205 	return NULL;
206 }
207 
208 static int da8xx_mstpri_probe(struct platform_device *pdev)
209 {
210 	const struct da8xx_mstpri_board_priorities *prio_list;
211 	const struct da8xx_mstpri_descr *prio_descr;
212 	const struct da8xx_mstpri_priority *prio;
213 	struct device *dev = &pdev->dev;
214 	struct resource *res;
215 	void __iomem *mstpri;
216 	u32 reg;
217 	int i;
218 
219 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
220 	mstpri = devm_ioremap_resource(dev, res);
221 	if (IS_ERR(mstpri)) {
222 		dev_err(dev, "unable to map MSTPRI registers\n");
223 		return PTR_ERR(mstpri);
224 	}
225 
226 	prio_list = da8xx_mstpri_get_board_prio();
227 	if (!prio_list) {
228 		dev_err(dev, "no master priorities defined for this board\n");
229 		return -EINVAL;
230 	}
231 
232 	for (i = 0; i < prio_list->numprio; i++) {
233 		prio = &prio_list->priorities[i];
234 		prio_descr = &da8xx_mstpri_priority_list[prio->which];
235 
236 		if (prio_descr->reg + sizeof(u32) > resource_size(res)) {
237 			dev_warn(dev, "register offset out of range\n");
238 			continue;
239 		}
240 
241 		reg = readl(mstpri + prio_descr->reg);
242 		reg &= ~prio_descr->mask;
243 		reg |= prio->val << prio_descr->shift;
244 
245 		writel(reg, mstpri + prio_descr->reg);
246 	}
247 
248 	return 0;
249 }
250 
251 static const struct of_device_id da8xx_mstpri_of_match[] = {
252 	{ .compatible = "ti,da850-mstpri", },
253 	{ },
254 };
255 
256 static struct platform_driver da8xx_mstpri_driver = {
257 	.probe = da8xx_mstpri_probe,
258 	.driver = {
259 		.name = "da8xx-mstpri",
260 		.of_match_table = da8xx_mstpri_of_match,
261 	},
262 };
263 module_platform_driver(da8xx_mstpri_driver);
264 
265 MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
266 MODULE_DESCRIPTION("TI da8xx master peripheral priority driver");
267 MODULE_LICENSE("GPL v2");
268