tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2017 Broadcom
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation version 2.
7 *
8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
9 * kind, whether express or implied; without even the implied warranty
10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14/*
15 * This driver provides reset support for Broadcom FlexRM ring manager
16 * to VFIO platform.
17 */
18
19#include <linux/delay.h>
20#include <linux/device.h>
21#include <linux/init.h>
22#include <linux/io.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
25
26#include "vfio_platform_private.h"
27
28/* FlexRM configuration */
29#define RING_REGS_SIZE 0x10000
30#define RING_VER_MAGIC 0x76303031
31
32/* Per-Ring register offsets */
33#define RING_VER 0x000
34#define RING_CONTROL 0x034
35#define RING_FLUSH_DONE 0x038
36
37/* Register RING_CONTROL fields */
38#define CONTROL_FLUSH_SHIFT 5
39
40/* Register RING_FLUSH_DONE fields */
41#define FLUSH_DONE_MASK 0x1
42
43static int vfio_platform_bcmflexrm_shutdown(void __iomem *ring)
44{
45 unsigned int timeout;
46
47 /* Disable/inactivate ring */
48 writel_relaxed(0x0, ring + RING_CONTROL);
49
50 /* Set ring flush state */
51 timeout = 1000; /* timeout of 1s */
52 writel_relaxed(BIT(CONTROL_FLUSH_SHIFT), ring + RING_CONTROL);
53 do {
54 if (readl_relaxed(ring + RING_FLUSH_DONE) &
55 FLUSH_DONE_MASK)
56 break;
57 mdelay(1);
58 } while (--timeout);
59 if (!timeout)
60 return -ETIMEDOUT;
61
62 /* Clear ring flush state */
63 timeout = 1000; /* timeout of 1s */
64 writel_relaxed(0x0, ring + RING_CONTROL);
65 do {
66 if (!(readl_relaxed(ring + RING_FLUSH_DONE) &
67 FLUSH_DONE_MASK))
68 break;
69 mdelay(1);
70 } while (--timeout);
71 if (!timeout)
72 return -ETIMEDOUT;
73
74 return 0;
75}
76
77static int vfio_platform_bcmflexrm_reset(struct vfio_platform_device *vdev)
78{
79 void __iomem *ring;
80 int rc = 0, ret = 0, ring_num = 0;
81 struct vfio_platform_region *reg = &vdev->regions[0];
82
83 /* Map FlexRM ring registers if not mapped */
84 if (!reg->ioaddr) {
85 reg->ioaddr = ioremap_nocache(reg->addr, reg->size);
86 if (!reg->ioaddr)
87 return -ENOMEM;
88 }
89
90 /* Discover and shutdown each FlexRM ring */
91 for (ring = reg->ioaddr;
92 ring < (reg->ioaddr + reg->size); ring += RING_REGS_SIZE) {
93 if (readl_relaxed(ring + RING_VER) == RING_VER_MAGIC) {
94 rc = vfio_platform_bcmflexrm_shutdown(ring);
95 if (rc) {
96 dev_warn(vdev->device,
97 "FlexRM ring%d shutdown error %d\n",
98 ring_num, rc);
99 ret |= rc;
100 }
101 ring_num++;
102 }
103 }
104
105 return ret;
106}
107
108module_vfio_reset_handler("brcm,iproc-flexrm-mbox",
109 vfio_platform_bcmflexrm_reset);
110
111MODULE_LICENSE("GPL v2");
112MODULE_AUTHOR("Anup Patel <anup.patel@broadcom.com>");
113MODULE_DESCRIPTION("Reset support for Broadcom FlexRM VFIO platform device");