diff options
author | David S. Miller <davem@davemloft.net> | 2011-09-22 03:23:13 -0400 |
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committer | David S. Miller <davem@davemloft.net> | 2011-09-22 03:23:13 -0400 |
commit | 8decf868790b48a727d7e7ca164f2bcd3c1389c0 (patch) | |
tree | b759a5f861f842af7ea76f9011b579d06e9d5508 /tools/power/cpupower/utils/helpers/sysfs.c | |
parent | 3fc72370186be2f9d4d6ef06d99e1caa5d92c564 (diff) | |
parent | d93dc5c4478c1fd5de85a3e8aece9aad7bbae044 (diff) |
Merge branch 'master' of github.com:davem330/net
Conflicts:
MAINTAINERS
drivers/net/Kconfig
drivers/net/ethernet/broadcom/bnx2x/bnx2x_link.c
drivers/net/ethernet/broadcom/tg3.c
drivers/net/wireless/iwlwifi/iwl-pci.c
drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c
drivers/net/wireless/rt2x00/rt2800usb.c
drivers/net/wireless/wl12xx/main.c
Diffstat (limited to 'tools/power/cpupower/utils/helpers/sysfs.c')
-rw-r--r-- | tools/power/cpupower/utils/helpers/sysfs.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c index 55e2466674c6..c6343024a611 100644 --- a/tools/power/cpupower/utils/helpers/sysfs.c +++ b/tools/power/cpupower/utils/helpers/sysfs.c @@ -56,6 +56,56 @@ static unsigned int sysfs_write_file(const char *path, return (unsigned int) numwrite; } +/* + * Detect whether a CPU is online + * + * Returns: + * 1 -> if CPU is online + * 0 -> if CPU is offline + * negative errno values in error case + */ +int sysfs_is_cpu_online(unsigned int cpu) +{ + char path[SYSFS_PATH_MAX]; + int fd; + ssize_t numread; + unsigned long long value; + char linebuf[MAX_LINE_LEN]; + char *endp; + struct stat statbuf; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u", cpu); + + if (stat(path, &statbuf) != 0) + return 0; + + /* + * kernel without CONFIG_HOTPLUG_CPU + * -> cpuX directory exists, but not cpuX/online file + */ + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online", cpu); + if (stat(path, &statbuf) != 0) + return 1; + + fd = open(path, O_RDONLY); + if (fd == -1) + return -errno; + + numread = read(fd, linebuf, MAX_LINE_LEN - 1); + if (numread < 1) { + close(fd); + return -EIO; + } + linebuf[numread] = '\0'; + close(fd); + + value = strtoull(linebuf, &endp, 0); + if (value > 1 || value < 0) + return -EINVAL; + + return value; +} + /* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */ /* |