1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2022 Microsoft Corporation <www.microsoft.com>
* Stephen Carlson <stcarlso@linux.microsoft.com>
*
* PCI Express Maximum Packet Size (MPS) configuration
*/
#include <bootretry.h>
#include <cli.h>
#include <command.h>
#include <console.h>
#include <dm.h>
#include <init.h>
#include <asm/processor.h>
#include <asm/io.h>
#include <pci.h>
#define PCI_MPS_SAFE 0
#define PCI_MPS_PEER2PEER 1
static int pci_mps_find_safe(struct udevice *bus, unsigned int *min_mps,
unsigned int *n)
{
struct udevice *dev;
int res = 0, addr;
unsigned int mpss;
u32 regval;
if (!min_mps || !n)
return -EINVAL;
for (device_find_first_child(bus, &dev);
dev;
device_find_next_child(&dev)) {
addr = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
if (addr <= 0)
continue;
res = dm_pci_read_config32(dev, addr + PCI_EXP_DEVCAP,
®val);
if (res != 0)
return res;
mpss = (unsigned int)(regval & PCI_EXP_DEVCAP_PAYLOAD);
*n += 1;
if (mpss < *min_mps)
*min_mps = mpss;
}
return res;
}
static int pci_mps_set_bus(struct udevice *bus, unsigned int target)
{
struct udevice *dev;
u32 mpss, target_mps = (u32)(target << 5);
u16 mps;
int res = 0, addr;
for (device_find_first_child(bus, &dev);
dev && res == 0;
device_find_next_child(&dev)) {
addr = dm_pci_find_capability(dev, PCI_CAP_ID_EXP);
if (addr <= 0)
continue;
res = dm_pci_read_config32(dev, addr + PCI_EXP_DEVCAP,
&mpss);
if (res != 0)
return res;
/* Do not set device above its maximum MPSS */
mpss = (mpss & PCI_EXP_DEVCAP_PAYLOAD) << 5;
if (target_mps < mpss)
mps = (u16)target_mps;
else
mps = (u16)mpss;
res = dm_pci_clrset_config16(dev, addr + PCI_EXP_DEVCTL,
PCI_EXP_DEVCTL_PAYLOAD, mps);
}
return res;
}
/*
* Sets the MPS of each PCI Express device to the specified policy.
*/
static int pci_mps_set(int policy)
{
struct udevice *bus;
int i, res = 0;
/* 0 = 128B, min value for hotplug */
unsigned int mps = 0;
if (policy == PCI_MPS_SAFE) {
unsigned int min_mps = PCI_EXP_DEVCAP_PAYLOAD_4096B, n = 0;
/* Find maximum MPS supported by all devices */
for (i = 0;
uclass_get_device_by_seq(UCLASS_PCI, i, &bus) == 0 &&
res == 0;
i++)
res = pci_mps_find_safe(bus, &min_mps, &n);
/* If no devices were found, do not reconfigure */
if (n == 0)
return res;
mps = min_mps;
}
/* This message is checked by the sandbox test */
printf("Setting MPS of all devices to %uB\n", 128U << mps);
for (i = 0;
uclass_get_device_by_seq(UCLASS_PCI, i, &bus) == 0 && res == 0;
i++)
res = pci_mps_set_bus(bus, mps);
return res;
}
/*
* PCI MPS tuning commands
*
* Syntax:
* pci_mps safe
* pci_mps peer2peer
*/
static int do_pci_mps(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
char cmd = 'u';
int ret = 0;
if (argc > 1)
cmd = argv[1][0];
switch (cmd) {
case 's': /* safe */
ret = pci_mps_set(PCI_MPS_SAFE);
break;
case 'p': /* peer2peer/hotplug */
ret = pci_mps_set(PCI_MPS_PEER2PEER);
break;
default: /* usage, help */
goto usage;
}
return ret;
usage:
return CMD_RET_USAGE;
}
/***************************************************/
U_BOOT_LONGHELP(pci_mps,
"safe\n"
" - Set PCI Express MPS of all devices to safe values\n"
"pci_mps peer2peer\n"
" - Set PCI Express MPS of all devices to support hotplug and peer-to-peer DMA\n");
U_BOOT_CMD(pci_mps, 2, 0, do_pci_mps,
"configure PCI Express MPS", pci_mps_help_text);
|
