1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2017 Broadcom
4  */
5 
6 /*
7  * This driver provides reset support for Broadcom FlexRM ring manager
8  * to VFIO platform.
9  */
10 
11 #include <linux/delay.h>
12 #include <linux/device.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 
18 #include "../vfio_platform_private.h"
19 
20 /* FlexRM configuration */
21 #define RING_REGS_SIZE					0x10000
22 #define RING_VER_MAGIC					0x76303031
23 
24 /* Per-Ring register offsets */
25 #define RING_VER					0x000
26 #define RING_CONTROL					0x034
27 #define RING_FLUSH_DONE					0x038
28 
29 /* Register RING_CONTROL fields */
30 #define CONTROL_FLUSH_SHIFT				5
31 
32 /* Register RING_FLUSH_DONE fields */
33 #define FLUSH_DONE_MASK					0x1
34 
vfio_platform_bcmflexrm_shutdown(void __iomem * ring)35 static int vfio_platform_bcmflexrm_shutdown(void __iomem *ring)
36 {
37 	unsigned int timeout;
38 
39 	/* Disable/inactivate ring */
40 	writel_relaxed(0x0, ring + RING_CONTROL);
41 
42 	/* Set ring flush state */
43 	timeout = 1000; /* timeout of 1s */
44 	writel_relaxed(BIT(CONTROL_FLUSH_SHIFT), ring + RING_CONTROL);
45 	do {
46 		if (readl_relaxed(ring + RING_FLUSH_DONE) &
47 		    FLUSH_DONE_MASK)
48 			break;
49 		mdelay(1);
50 	} while (--timeout);
51 	if (!timeout)
52 		return -ETIMEDOUT;
53 
54 	/* Clear ring flush state */
55 	timeout = 1000; /* timeout of 1s */
56 	writel_relaxed(0x0, ring + RING_CONTROL);
57 	do {
58 		if (!(readl_relaxed(ring + RING_FLUSH_DONE) &
59 		      FLUSH_DONE_MASK))
60 			break;
61 		mdelay(1);
62 	} while (--timeout);
63 	if (!timeout)
64 		return -ETIMEDOUT;
65 
66 	return 0;
67 }
68 
vfio_platform_bcmflexrm_reset(struct vfio_platform_device * vdev)69 static int vfio_platform_bcmflexrm_reset(struct vfio_platform_device *vdev)
70 {
71 	void __iomem *ring;
72 	int rc = 0, ret = 0, ring_num = 0;
73 	struct vfio_platform_region *reg = &vdev->regions[0];
74 
75 	/* Map FlexRM ring registers if not mapped */
76 	if (!reg->ioaddr) {
77 		reg->ioaddr = ioremap(reg->addr, reg->size);
78 		if (!reg->ioaddr)
79 			return -ENOMEM;
80 	}
81 
82 	/* Discover and shutdown each FlexRM ring */
83 	for (ring = reg->ioaddr;
84 	     ring < (reg->ioaddr + reg->size); ring += RING_REGS_SIZE) {
85 		if (readl_relaxed(ring + RING_VER) == RING_VER_MAGIC) {
86 			rc = vfio_platform_bcmflexrm_shutdown(ring);
87 			if (rc) {
88 				dev_warn(vdev->device,
89 					 "FlexRM ring%d shutdown error %d\n",
90 					 ring_num, rc);
91 				ret |= rc;
92 			}
93 			ring_num++;
94 		}
95 	}
96 
97 	return ret;
98 }
99 
100 module_vfio_reset_handler("brcm,iproc-flexrm-mbox",
101 			  vfio_platform_bcmflexrm_reset);
102 
103 MODULE_LICENSE("GPL v2");
104 MODULE_AUTHOR("Anup Patel <anup.patel@broadcom.com>");
105 MODULE_DESCRIPTION("Reset support for Broadcom FlexRM VFIO platform device");
106