From a3c8121b8724c3d496dc00201ab40e8313edcf0d Mon Sep 17 00:00:00 2001 From: Daniel Drake Date: Tue, 27 Mar 2012 16:07:40 +0100 Subject: [PATCH] x86/olpc: Add debugfs interface for EC commands Add a debugfs interface for sending commands to the OLPC Embedded Controller (EC) and reading the responses. The EC provides functionality for machine identification, battery and AC control, wakeup control, etc. Having a debugfs interface available is useful for EC development and debugging. Based on code by Paul Fox (who also approves of the end result). Signed-off-by: Daniel Drake Acked-by: Paul Fox Cc: "H. Peter Anvin" Cc: Andres Salomon Link: http://lkml.kernel.org/r/20120327150740.667D09D401E@zog.reactivated.net Signed-off-by: Ingo Molnar --- Documentation/ABI/testing/debugfs-olpc | 16 +++++ arch/x86/platform/olpc/olpc.c | 97 ++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-olpc diff --git a/Documentation/ABI/testing/debugfs-olpc b/Documentation/ABI/testing/debugfs-olpc new file mode 100644 index 000000000000..bd76cc6d55f9 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-olpc @@ -0,0 +1,16 @@ +What: /sys/kernel/debug/olpc-ec/cmd +Date: Dec 2011 +KernelVersion: 3.4 +Contact: devel@lists.laptop.org +Description: + +A generic interface for executing OLPC Embedded Controller commands and +reading their responses. + +To execute a command, write data with the format: CC:N A A A A +CC is the (hex) command, N is the count of expected reply bytes, and A A A A +are optional (hex) arguments. + +To read the response (if any), read from the generic node after executing +a command. Hex reply bytes will be returned, *whether or not* they came from +the immediately previous command. diff --git a/arch/x86/platform/olpc/olpc.c b/arch/x86/platform/olpc/olpc.c index 7cce722667b8..a4bee53c2e54 100644 --- a/arch/x86/platform/olpc/olpc.c +++ b/arch/x86/platform/olpc/olpc.c @@ -20,6 +20,8 @@ #include #include #include +#include +#include #include #include @@ -31,6 +33,15 @@ EXPORT_SYMBOL_GPL(olpc_platform_info); static DEFINE_SPINLOCK(ec_lock); +/* debugfs interface to EC commands */ +#define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */ +#define EC_MAX_CMD_REPLY (8) + +static struct dentry *ec_debugfs_dir; +static DEFINE_MUTEX(ec_debugfs_cmd_lock); +static unsigned char ec_debugfs_resp[EC_MAX_CMD_REPLY]; +static unsigned int ec_debugfs_resp_bytes; + /* EC event mask to be applied during suspend (defining wakeup sources). */ static u16 ec_wakeup_mask; @@ -269,6 +280,91 @@ int olpc_ec_sci_query(u16 *sci_value) } EXPORT_SYMBOL_GPL(olpc_ec_sci_query); +static ssize_t ec_debugfs_cmd_write(struct file *file, const char __user *buf, + size_t size, loff_t *ppos) +{ + int i, m; + unsigned char ec_cmd[EC_MAX_CMD_ARGS]; + unsigned int ec_cmd_int[EC_MAX_CMD_ARGS]; + char cmdbuf[64]; + int ec_cmd_bytes; + + mutex_lock(&ec_debugfs_cmd_lock); + + size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size); + + m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0], + &ec_debugfs_resp_bytes, + &ec_cmd_int[1], &ec_cmd_int[2], &ec_cmd_int[3], + &ec_cmd_int[4], &ec_cmd_int[5]); + if (m < 2 || ec_debugfs_resp_bytes > EC_MAX_CMD_REPLY) { + /* reset to prevent overflow on read */ + ec_debugfs_resp_bytes = 0; + + printk(KERN_DEBUG "olpc-ec: bad ec cmd: " + "cmd:response-count [arg1 [arg2 ...]]\n"); + size = -EINVAL; + goto out; + } + + /* convert scanf'd ints to char */ + ec_cmd_bytes = m - 2; + for (i = 0; i <= ec_cmd_bytes; i++) + ec_cmd[i] = ec_cmd_int[i]; + + printk(KERN_DEBUG "olpc-ec: debugfs cmd 0x%02x with %d args " + "%02x %02x %02x %02x %02x, want %d returns\n", + ec_cmd[0], ec_cmd_bytes, ec_cmd[1], ec_cmd[2], ec_cmd[3], + ec_cmd[4], ec_cmd[5], ec_debugfs_resp_bytes); + + olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1], + ec_cmd_bytes, ec_debugfs_resp, ec_debugfs_resp_bytes); + + printk(KERN_DEBUG "olpc-ec: response " + "%02x %02x %02x %02x %02x %02x %02x %02x (%d bytes expected)\n", + ec_debugfs_resp[0], ec_debugfs_resp[1], ec_debugfs_resp[2], + ec_debugfs_resp[3], ec_debugfs_resp[4], ec_debugfs_resp[5], + ec_debugfs_resp[6], ec_debugfs_resp[7], ec_debugfs_resp_bytes); + +out: + mutex_unlock(&ec_debugfs_cmd_lock); + return size; +} + +static ssize_t ec_debugfs_cmd_read(struct file *file, char __user *buf, + size_t size, loff_t *ppos) +{ + unsigned int i, r; + char *rp; + char respbuf[64]; + + mutex_lock(&ec_debugfs_cmd_lock); + rp = respbuf; + rp += sprintf(rp, "%02x", ec_debugfs_resp[0]); + for (i = 1; i < ec_debugfs_resp_bytes; i++) + rp += sprintf(rp, ", %02x", ec_debugfs_resp[i]); + mutex_unlock(&ec_debugfs_cmd_lock); + rp += sprintf(rp, "\n"); + + r = rp - respbuf; + return simple_read_from_buffer(buf, size, ppos, respbuf, r); +} + +static const struct file_operations ec_debugfs_genops = { + .write = ec_debugfs_cmd_write, + .read = ec_debugfs_cmd_read, +}; + +static void setup_debugfs(void) +{ + ec_debugfs_dir = debugfs_create_dir("olpc-ec", 0); + if (ec_debugfs_dir == ERR_PTR(-ENODEV)) + return; + + debugfs_create_file("cmd", 0600, ec_debugfs_dir, NULL, + &ec_debugfs_genops); +} + static int olpc_ec_suspend(void) { return olpc_ec_mask_write(ec_wakeup_mask); @@ -372,6 +468,7 @@ static int __init olpc_init(void) } register_syscore_ops(&olpc_syscore_ops); + setup_debugfs(); return 0; } -- 2.20.1