tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
7 */
8#include <linux/delay.h>
9#include <linux/kernel.h>
10#include <linux/spinlock.h>
11#include <linux/init.h>
12#include <linux/io.h>
13#include <linux/errno.h>
14
15#define PIC32_NULL 0x00
16#define PIC32_RD 0x01
17#define PIC32_SYSRD 0x02
18#define PIC32_WR 0x10
19#define PIC32_SYSWR 0x20
20#define PIC32_IRQ_CLR 0x40
21#define PIC32_STATUS 0x80
22
23#define DELAY() udelay(100) /* FIXME: needed? */
24
25/* spinlock to ensure atomic access to PIC32 */
26static DEFINE_SPINLOCK(pic32_bus_lock);
27
28/* FIXME: io_remap these */
29static void __iomem *bus_xfer = (void __iomem *)0xbf000600;
30static void __iomem *bus_status = (void __iomem *)0xbf000060;
31
32static inline unsigned int ioready(void)
33{
34 return readl(bus_status) & 1;
35}
36
37static inline void wait_ioready(void)
38{
39 do { } while (!ioready());
40}
41
42static inline void wait_ioclear(void)
43{
44 do { } while (ioready());
45}
46
47static inline void check_ioclear(void)
48{
49 if (ioready()) {
50 pr_debug("ioclear: initially busy\n");
51 do {
52 (void) readl(bus_xfer);
53 DELAY();
54 } while (ioready());
55 pr_debug("ioclear: cleared busy\n");
56 }
57}
58
59u32 pic32_bus_readl(u32 reg)
60{
61 unsigned long flags;
62 u32 status, val;
63
64 spin_lock_irqsave(&pic32_bus_lock, flags);
65
66 check_ioclear();
67
68 writel((PIC32_RD << 24) | (reg & 0x00ffffff), bus_xfer);
69 DELAY();
70 wait_ioready();
71 status = readl(bus_xfer);
72 DELAY();
73 val = readl(bus_xfer);
74 wait_ioclear();
75
76 pr_debug("pic32_bus_readl: *%x -> %x (status=%x)\n", reg, val, status);
77
78 spin_unlock_irqrestore(&pic32_bus_lock, flags);
79
80 return val;
81}
82
83void pic32_bus_writel(u32 val, u32 reg)
84{
85 unsigned long flags;
86 u32 status;
87
88 spin_lock_irqsave(&pic32_bus_lock, flags);
89
90 check_ioclear();
91
92 writel((PIC32_WR << 24) | (reg & 0x00ffffff), bus_xfer);
93 DELAY();
94 writel(val, bus_xfer);
95 DELAY();
96 wait_ioready();
97 status = readl(bus_xfer);
98 wait_ioclear();
99
100 pr_debug("pic32_bus_writel: *%x <- %x (status=%x)\n", reg, val, status);
101
102 spin_unlock_irqrestore(&pic32_bus_lock, flags);
103}