![Arjan van de Ven](/assets/img/avatar_default.png)
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. [akpm@osdl.org: sparc64 fix] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
187 lines
3.9 KiB
C
187 lines
3.9 KiB
C
/* apc - Driver implementation for power management functions
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* of Aurora Personality Chip (APC) on SPARCstation-4/5 and
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* derivatives.
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*
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* Copyright (c) 2002 Eric Brower (ebrower@usa.net)
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*/
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <linux/pm.h>
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#include <asm/io.h>
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#include <asm/sbus.h>
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#include <asm/oplib.h>
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#include <asm/uaccess.h>
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#include <asm/auxio.h>
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#include <asm/apc.h>
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/* Debugging
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*
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* #define APC_DEBUG_LED
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*/
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#define APC_MINOR MISC_DYNAMIC_MINOR
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#define APC_OBPNAME "power-management"
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#define APC_DEVNAME "apc"
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volatile static u8 __iomem *regs;
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static int apc_regsize;
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static int apc_no_idle __initdata = 0;
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#define apc_readb(offs) (sbus_readb(regs+offs))
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#define apc_writeb(val, offs) (sbus_writeb(val, regs+offs))
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/* Specify "apc=noidle" on the kernel command line to
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* disable APC CPU standby support. Certain prototype
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* systems (SPARCstation-Fox) do not play well with APC
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* CPU idle, so disable this if your system has APC and
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* crashes randomly.
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*/
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static int __init apc_setup(char *str)
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{
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if(!strncmp(str, "noidle", strlen("noidle"))) {
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apc_no_idle = 1;
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return 1;
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}
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return 0;
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}
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__setup("apc=", apc_setup);
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/*
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* CPU idle callback function
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* See .../arch/sparc/kernel/process.c
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*/
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void apc_swift_idle(void)
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{
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#ifdef APC_DEBUG_LED
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set_auxio(0x00, AUXIO_LED);
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#endif
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apc_writeb(apc_readb(APC_IDLE_REG) | APC_IDLE_ON, APC_IDLE_REG);
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#ifdef APC_DEBUG_LED
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set_auxio(AUXIO_LED, 0x00);
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#endif
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}
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static inline void apc_free(void)
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{
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sbus_iounmap(regs, apc_regsize);
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}
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static int apc_open(struct inode *inode, struct file *f)
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{
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return 0;
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}
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static int apc_release(struct inode *inode, struct file *f)
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{
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return 0;
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}
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static int apc_ioctl(struct inode *inode, struct file *f,
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unsigned int cmd, unsigned long __arg)
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{
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__u8 inarg, __user *arg;
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arg = (__u8 __user *) __arg;
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switch (cmd) {
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case APCIOCGFANCTL:
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if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
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return -EFAULT;
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break;
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case APCIOCGCPWR:
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if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
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return -EFAULT;
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break;
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case APCIOCGBPORT:
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if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
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return -EFAULT;
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break;
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case APCIOCSFANCTL:
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if (get_user(inarg, arg))
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return -EFAULT;
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apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
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break;
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case APCIOCSCPWR:
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if (get_user(inarg, arg))
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return -EFAULT;
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apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
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break;
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case APCIOCSBPORT:
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if (get_user(inarg, arg))
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return -EFAULT;
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apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
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break;
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default:
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return -EINVAL;
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};
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return 0;
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}
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static const struct file_operations apc_fops = {
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.ioctl = apc_ioctl,
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.open = apc_open,
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.release = apc_release,
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};
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static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
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static int __init apc_probe(void)
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{
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struct sbus_bus *sbus = NULL;
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struct sbus_dev *sdev = NULL;
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int iTmp = 0;
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for_each_sbus(sbus) {
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for_each_sbusdev(sdev, sbus) {
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if (!strcmp(sdev->prom_name, APC_OBPNAME)) {
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goto sbus_done;
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}
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}
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}
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sbus_done:
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if (!sdev) {
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return -ENODEV;
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}
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apc_regsize = sdev->reg_addrs[0].reg_size;
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regs = sbus_ioremap(&sdev->resource[0], 0,
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apc_regsize, APC_OBPNAME);
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if(!regs) {
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printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
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return -ENODEV;
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}
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iTmp = misc_register(&apc_miscdev);
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if (iTmp != 0) {
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printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
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apc_free();
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return -ENODEV;
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}
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/* Assign power management IDLE handler */
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if(!apc_no_idle)
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pm_idle = apc_swift_idle;
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printk(KERN_INFO "%s: power management initialized%s\n",
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APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
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return 0;
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}
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/* This driver is not critical to the boot process
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* and is easiest to ioremap when SBus is already
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* initialized, so we install ourselves thusly:
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*/
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__initcall(apc_probe);
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