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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
/*
* Coherency fabric (Aurora) support for Armada 370 and XP platforms.
*
* Copyright (C) 2012 Marvell
*
* Yehuda Yitschak <yehuday@marvell.com>
* Gregory Clement <gregory.clement@free-electrons.com>
* Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* The Armada 370 and Armada XP SOCs have a coherency fabric which is
* responsible for ensuring hardware coherency between all CPUs and between
* CPUs and I/O masters. This file initializes the coherency fabric and
* supplies basic routines for configuring and controlling hardware coherency
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/smp.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <asm/smp_plat.h>
#include "armada-370-xp.h"
/*
* Some functions in this file are called very early during SMP
* initialization. At that time the device tree framework is not yet
* ready, and it is not possible to get the register address to
* ioremap it. That's why the pointer below is given with an initial
* value matching its virtual mapping
*/
static void __iomem *coherency_base = ARMADA_370_XP_REGS_VIRT_BASE + 0x20200;
static void __iomem *coherency_cpu_base;
/* Coherency fabric registers */
#define COHERENCY_FABRIC_CFG_OFFSET 0x4
#define IO_SYNC_BARRIER_CTL_OFFSET 0x0
static struct of_device_id of_coherency_table[] = {
{.compatible = "marvell,coherency-fabric"},
{ /* end of list */ },
};
#ifdef CONFIG_SMP
int coherency_get_cpu_count(void)
{
int reg, cnt;
reg = readl(coherency_base + COHERENCY_FABRIC_CFG_OFFSET);
cnt = (reg & 0xF) + 1;
return cnt;
}
#endif
/* Function defined in coherency_ll.S */
int ll_set_cpu_coherent(void __iomem *base_addr, unsigned int hw_cpu_id);
int set_cpu_coherent(unsigned int hw_cpu_id, int smp_group_id)
{
if (!coherency_base) {
pr_warn("Can't make CPU %d cache coherent.\n", hw_cpu_id);
pr_warn("Coherency fabric is not initialized\n");
return 1;
}
return ll_set_cpu_coherent(coherency_base, hw_cpu_id);
}
static inline void mvebu_hwcc_sync_io_barrier(void)
{
writel(0x1, coherency_cpu_base + IO_SYNC_BARRIER_CTL_OFFSET);
while (readl(coherency_cpu_base + IO_SYNC_BARRIER_CTL_OFFSET) & 0x1);
}
static dma_addr_t mvebu_hwcc_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
if (dir != DMA_TO_DEVICE)
mvebu_hwcc_sync_io_barrier();
return pfn_to_dma(dev, page_to_pfn(page)) + offset;
}
static void mvebu_hwcc_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
if (dir != DMA_TO_DEVICE)
mvebu_hwcc_sync_io_barrier();
}
static void mvebu_hwcc_dma_sync(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir)
{
if (dir != DMA_TO_DEVICE)
mvebu_hwcc_sync_io_barrier();
}
static struct dma_map_ops mvebu_hwcc_dma_ops = {
.alloc = arm_dma_alloc,
.free = arm_dma_free,
.mmap = arm_dma_mmap,
.map_page = mvebu_hwcc_dma_map_page,
.unmap_page = mvebu_hwcc_dma_unmap_page,
.get_sgtable = arm_dma_get_sgtable,
.map_sg = arm_dma_map_sg,
.unmap_sg = arm_dma_unmap_sg,
.sync_single_for_cpu = mvebu_hwcc_dma_sync,
.sync_single_for_device = mvebu_hwcc_dma_sync,
.sync_sg_for_cpu = arm_dma_sync_sg_for_cpu,
.sync_sg_for_device = arm_dma_sync_sg_for_device,
.set_dma_mask = arm_dma_set_mask,
};
static int mvebu_hwcc_platform_notifier(struct notifier_block *nb,
unsigned long event, void *__dev)
{
struct device *dev = __dev;
if (event != BUS_NOTIFY_ADD_DEVICE)
return NOTIFY_DONE;
set_dma_ops(dev, &mvebu_hwcc_dma_ops);
return NOTIFY_OK;
}
static struct notifier_block mvebu_hwcc_platform_nb = {
.notifier_call = mvebu_hwcc_platform_notifier,
};
/*
* Keep track of whether we have IO hardware coherency enabled or not.
* On Armada 370's we will not be using it for example. We need to make
* that available [through coherency_available()] so the mbus controller
* doesn't enable the IO coherency bit in the attribute bits of the
* chip selects.
*/
static int coherency_enabled;
int coherency_available(void)
{
return coherency_enabled;
}
int __init coherency_init(void)
{
struct device_node *np;
/*
* The coherency fabric is needed:
* - For coherency between processors on Armada XP, so only
* when SMP is enabled.
* - For coherency between the processor and I/O devices, but
* this coherency requires many pre-requisites (write
* allocate cache policy, shareable pages, SMP bit set) that
* are only meant in SMP situations.
*
* Note that this means that on Armada 370, there is currently
* no way to use hardware I/O coherency, because even when
* CONFIG_SMP is enabled, is_smp() returns false due to the
* Armada 370 being a single-core processor. To lift this
* limitation, we would have to find a way to make the cache
* policy set to write-allocate (on all Armada SoCs), and to
* set the shareable attribute in page tables (on all Armada
* SoCs except the Armada 370). Unfortunately, such decisions
* are taken very early in the kernel boot process, at a point
* where we don't know yet on which SoC we are running.
*/
if (!is_smp())
return 0;
np = of_find_matching_node(NULL, of_coherency_table);
if (np) {
pr_info("Initializing Coherency fabric\n");
coherency_base = of_iomap(np, 0);
coherency_cpu_base = of_iomap(np, 1);
set_cpu_coherent(cpu_logical_map(smp_processor_id()), 0);
coherency_enabled = 1;
bus_register_notifier(&platform_bus_type,
&mvebu_hwcc_platform_nb);
}
return 0;
}
|
