xref: /openbmc/linux/drivers/soc/gemini/soc-gemini.c (revision 68198dca)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2017 Linaro Ltd.
4  *
5  * Author: Linus Walleij <linus.walleij@linaro.org>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2, as
9  * published by the Free Software Foundation.
10  *
11  */
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/regmap.h>
16 #include <linux/of.h>
17 
18 #define GLOBAL_WORD_ID				0x00
19 #define GEMINI_GLOBAL_ARB1_CTRL			0x2c
20 #define GEMINI_ARB1_BURST_MASK			GENMASK(21, 16)
21 #define GEMINI_ARB1_BURST_SHIFT			16
22 /* These all define the priority on the BUS2 backplane */
23 #define GEMINI_ARB1_PRIO_MASK			GENMASK(9, 0)
24 #define GEMINI_ARB1_DMAC_HIGH_PRIO		BIT(0)
25 #define GEMINI_ARB1_IDE_HIGH_PRIO		BIT(1)
26 #define GEMINI_ARB1_RAID_HIGH_PRIO		BIT(2)
27 #define GEMINI_ARB1_SECURITY_HIGH_PRIO		BIT(3)
28 #define GEMINI_ARB1_GMAC0_HIGH_PRIO		BIT(4)
29 #define GEMINI_ARB1_GMAC1_HIGH_PRIO		BIT(5)
30 #define GEMINI_ARB1_USB0_HIGH_PRIO		BIT(6)
31 #define GEMINI_ARB1_USB1_HIGH_PRIO		BIT(7)
32 #define GEMINI_ARB1_PCI_HIGH_PRIO		BIT(8)
33 #define GEMINI_ARB1_TVE_HIGH_PRIO		BIT(9)
34 
35 #define GEMINI_DEFAULT_BURST_SIZE		0x20
36 #define GEMINI_DEFAULT_PRIO			(GEMINI_ARB1_GMAC0_HIGH_PRIO | \
37 						 GEMINI_ARB1_GMAC1_HIGH_PRIO)
38 
gemini_soc_init(void)39 static int __init gemini_soc_init(void)
40 {
41 	struct regmap *map;
42 	u32 rev;
43 	u32 val;
44 	int ret;
45 
46 	/* Multiplatform guard, only proceed on Gemini */
47 	if (!of_machine_is_compatible("cortina,gemini"))
48 		return 0;
49 
50 	map = syscon_regmap_lookup_by_compatible("cortina,gemini-syscon");
51 	if (IS_ERR(map))
52 		return PTR_ERR(map);
53 	ret = regmap_read(map, GLOBAL_WORD_ID, &rev);
54 	if (ret)
55 		return ret;
56 
57 	val = (GEMINI_DEFAULT_BURST_SIZE << GEMINI_ARB1_BURST_SHIFT) |
58 		GEMINI_DEFAULT_PRIO;
59 
60 	/* Set up system arbitration */
61 	regmap_update_bits(map,
62 			   GEMINI_GLOBAL_ARB1_CTRL,
63 			   GEMINI_ARB1_BURST_MASK | GEMINI_ARB1_PRIO_MASK,
64 			   val);
65 
66 	pr_info("Gemini SoC %04x revision %02x, set arbitration %08x\n",
67 		rev >> 8, rev & 0xff, val);
68 
69 	return 0;
70 }
71 subsys_initcall(gemini_soc_init);
72