thinkpad-acpi: volume subdriver rewrite

I don't trust the coupled EC writes and SMI calls the current volume
control code does very much, although it is exactly what the IBM DSDTs
seem to do (they never do more than a single step though).

Change the driver to stop issuing SMIs, and just drive the EC directly
to the desired level (DSDTs seem to confirm this will work even on
very old models like the 570 and 600e/x).

We checkpoint directly to NVRAM (this can be turned off) at
suspend/shutdown/driver unload, which from what I can see in tbp,
should also work on every ThinkPad.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Lorne Applebaum <lorne.applebaum@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 282 insertions, 58 deletions

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 05714abf5a8..a2f5312c6a4 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -231,6 +231,7 @@ enum tpacpi_hkey_event_t {
 #define TPACPI_DBG_HKEY		0x0008
 #define TPACPI_DBG_FAN		0x0010
 #define TPACPI_DBG_BRGHT	0x0020
+#define TPACPI_DBG_MIXER	0x0040
 
 #define onoff(status, bit) ((status) & (1 << (bit)) ? "on" : "off")
 #define enabled(status, bit) ((status) & (1 << (bit)) ? "enabled" : "disabled")
@@ -6375,21 +6376,260 @@ static struct ibm_struct brightness_driver_data = {
  * Volume subdriver
  */
 
-static int volume_offset = 0x30;
+/*
+ * IBM ThinkPads have a simple volume controller with MUTE gating.
+ * Very early Lenovo ThinkPads follow the IBM ThinkPad spec.
+ *
+ * Since the *61 series (and probably also the later *60 series), Lenovo
+ * ThinkPads only implement the MUTE gate.
+ *
+ * EC register 0x30
+ *   Bit 6: MUTE (1 mutes sound)
+ *   Bit 3-0: Volume
+ *   Other bits should be zero as far as we know.
+ *
+ * This is also stored in CMOS NVRAM, byte 0x60, bit 6 (MUTE), and
+ * bits 3-0 (volume).  Other bits in NVRAM may have other functions,
+ * such as bit 7 which is used to detect repeated presses of MUTE,
+ * and we leave them unchanged.
+ */
+
+enum {
+	TP_EC_AUDIO = 0x30,
+
+	/* TP_EC_AUDIO bits */
+	TP_EC_AUDIO_MUTESW = 6,
+
+	/* TP_EC_AUDIO bitmasks */
+	TP_EC_AUDIO_LVL_MSK = 0x0F,
+	TP_EC_AUDIO_MUTESW_MSK = (1 << TP_EC_AUDIO_MUTESW),
+
+	/* Maximum volume */
+	TP_EC_VOLUME_MAX = 14,
+};
+
+enum tpacpi_volume_access_mode {
+	TPACPI_VOL_MODE_AUTO = 0,	/* Not implemented yet */
+	TPACPI_VOL_MODE_EC,		/* Pure EC control */
+	TPACPI_VOL_MODE_UCMS_STEP,	/* UCMS step-based control: N/A */
+	TPACPI_VOL_MODE_ECNVRAM,	/* EC control w/ NVRAM store */
+	TPACPI_VOL_MODE_MAX
+};
+
+static enum tpacpi_volume_access_mode volume_mode =
+	TPACPI_VOL_MODE_MAX;
+
+
+/*
+ * Used to syncronize writers to TP_EC_AUDIO and
+ * TP_NVRAM_ADDR_MIXER, as we need to do read-modify-write
+ */
+static struct mutex volume_mutex;
+
+static void tpacpi_volume_checkpoint_nvram(void)
+{
+	u8 lec = 0;
+	u8 b_nvram;
+	const u8 ec_mask = TP_EC_AUDIO_LVL_MSK | TP_EC_AUDIO_MUTESW_MSK;
+
+	if (volume_mode != TPACPI_VOL_MODE_ECNVRAM)
+		return;
+
+	vdbg_printk(TPACPI_DBG_MIXER,
+		"trying to checkpoint mixer state to NVRAM...\n");
+
+	if (mutex_lock_killable(&volume_mutex) < 0)
+		return;
+
+	if (unlikely(!acpi_ec_read(TP_EC_AUDIO, &lec)))
+		goto unlock;
+	lec &= ec_mask;
+	b_nvram = nvram_read_byte(TP_NVRAM_ADDR_MIXER);
+
+	if (lec != (b_nvram & ec_mask)) {
+		/* NVRAM needs update */
+		b_nvram &= ~ec_mask;
+		b_nvram |= lec;
+		nvram_write_byte(b_nvram, TP_NVRAM_ADDR_MIXER);
+		dbg_printk(TPACPI_DBG_MIXER,
+			   "updated NVRAM mixer status to 0x%02x (0x%02x)\n",
+			   (unsigned int) lec, (unsigned int) b_nvram);
+	} else {
+		vdbg_printk(TPACPI_DBG_MIXER,
+			   "NVRAM mixer status already is 0x%02x (0x%02x)\n",
+			   (unsigned int) lec, (unsigned int) b_nvram);
+	}
+
+unlock:
+	mutex_unlock(&volume_mutex);
+}
+
+static int volume_get_status_ec(u8 *status)
+{
+	u8 s;
+
+	if (!acpi_ec_read(TP_EC_AUDIO, &s))
+		return -EIO;
+
+	*status = s;
+
+	dbg_printk(TPACPI_DBG_MIXER, "status 0x%02x\n", s);
+
+	return 0;
+}
+
+static int volume_get_status(u8 *status)
+{
+	return volume_get_status_ec(status);
+}
+
+static int volume_set_status_ec(const u8 status)
+{
+	if (!acpi_ec_write(TP_EC_AUDIO, status))
+		return -EIO;
+
+	dbg_printk(TPACPI_DBG_MIXER, "set EC mixer to 0x%02x\n", status);
+
+	return 0;
+}
+
+static int volume_set_status(const u8 status)
+{
+	return volume_set_status_ec(status);
+}
+
+static int volume_set_mute_ec(const bool mute)
+{
+	int rc;
+	u8 s, n;
+
+	if (mutex_lock_killable(&volume_mutex) < 0)
+		return -EINTR;
+
+	rc = volume_get_status_ec(&s);
+	if (rc)
+		goto unlock;
+
+	n = (mute) ? s | TP_EC_AUDIO_MUTESW_MSK :
+		     s & ~TP_EC_AUDIO_MUTESW_MSK;
+
+	if (n != s)
+		rc = volume_set_status_ec(n);
+
+unlock:
+	mutex_unlock(&volume_mutex);
+	return rc;
+}
+
+static int volume_set_mute(const bool mute)
+{
+	dbg_printk(TPACPI_DBG_MIXER, "trying to %smute\n",
+		   (mute) ? "" : "un");
+	return volume_set_mute_ec(mute);
+}
+
+static int volume_set_volume_ec(const u8 vol)
+{
+	int rc;
+	u8 s, n;
+
+	if (vol > TP_EC_VOLUME_MAX)
+		return -EINVAL;
+
+	if (mutex_lock_killable(&volume_mutex) < 0)
+		return -EINTR;
+
+	rc = volume_get_status_ec(&s);
+	if (rc)
+		goto unlock;
+
+	n = (s & ~TP_EC_AUDIO_LVL_MSK) | vol;
+
+	if (n != s)
+		rc = volume_set_status_ec(n);
+
+unlock:
+	mutex_unlock(&volume_mutex);
+	return rc;
+}
+
+static int volume_set_volume(const u8 vol)
+{
+	dbg_printk(TPACPI_DBG_MIXER,
+		   "trying to set volume level to %hu\n", vol);
+	return volume_set_volume_ec(vol);
+}
+
+static void volume_suspend(pm_message_t state)
+{
+	tpacpi_volume_checkpoint_nvram();
+}
+
+static void volume_shutdown(void)
+{
+	tpacpi_volume_checkpoint_nvram();
+}
+
+static void volume_exit(void)
+{
+	tpacpi_volume_checkpoint_nvram();
+}
+
+static int __init volume_init(struct ibm_init_struct *iibm)
+{
+	vdbg_printk(TPACPI_DBG_INIT, "initializing volume subdriver\n");
+
+	mutex_init(&volume_mutex);
+
+	/*
+	 * Check for module parameter bogosity, note that we
+	 * init volume_mode to TPACPI_VOL_MODE_MAX in order to be
+	 * able to detect "unspecified"
+	 */
+	if (volume_mode > TPACPI_VOL_MODE_MAX)
+		return -EINVAL;
+
+	if (volume_mode == TPACPI_VOL_MODE_UCMS_STEP) {
+		printk(TPACPI_ERR
+			"UCMS step volume mode not implemented, "
+			"please contact %s\n", TPACPI_MAIL);
+		return 1;
+	}
+
+	if (volume_mode == TPACPI_VOL_MODE_AUTO ||
+	    volume_mode == TPACPI_VOL_MODE_MAX) {
+		volume_mode = TPACPI_VOL_MODE_ECNVRAM;
+
+		dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_MIXER,
+				"driver auto-selected volume_mode=%d\n",
+				volume_mode);
+	} else {
+		dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_MIXER,
+				"using user-supplied volume_mode=%d\n",
+				volume_mode);
+	}
+
+	vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_MIXER,
+			"volume is supported\n");
+
+	return 0;
+}
 
 static int volume_read(char *p)
 {
 	int len = 0;
-	u8 level;
+	u8 status;
 
-	if (!acpi_ec_read(volume_offset, &level)) {
+	if (volume_get_status(&status) < 0) {
 		len += sprintf(p + len, "level:\t\tunreadable\n");
 	} else {
-		len += sprintf(p + len, "level:\t\t%d\n", level & 0xf);
-		len += sprintf(p + len, "mute:\t\t%s\n", onoff(level, 6));
+		len += sprintf(p + len, "level:\t\t%d\n",
+				status & TP_EC_AUDIO_LVL_MSK);
+		len += sprintf(p + len, "mute:\t\t%s\n",
+				onoff(status, TP_EC_AUDIO_MUTESW));
 		len += sprintf(p + len, "commands:\tup, down, mute\n");
 		len += sprintf(p + len, "commands:\tlevel <level>"
-			       " (<level> is 0-15)\n");
+			       " (<level> is 0-%d)\n", TP_EC_VOLUME_MAX);
 	}
 
 	return len;
@@ -6397,77 +6637,55 @@ static int volume_read(char *p)
 
 static int volume_write(char *buf)
 {
-	int cmos_cmd, inc, i;
-	u8 level, mute;
-	int new_level, new_mute;
+	u8 s;
+	u8 new_level, new_mute;
+	int l;
 	char *cmd;
+	int rc;
 
-	while ((cmd = next_cmd(&buf))) {
-		if (!acpi_ec_read(volume_offset, &level))
-			return -EIO;
-		new_mute = mute = level & 0x40;
-		new_level = level = level & 0xf;
+	rc = volume_get_status(&s);
+	if (rc < 0)
+		return rc;
 
+	new_level = s & TP_EC_AUDIO_LVL_MSK;
+	new_mute  = s & TP_EC_AUDIO_MUTESW_MSK;
+
+	while ((cmd = next_cmd(&buf))) {
 		if (strlencmp(cmd, "up") == 0) {
-			if (mute)
+			if (new_mute)
 				new_mute = 0;
-			else
-				new_level = level == 15 ? 15 : level + 1;
+			else if (new_level < TP_EC_VOLUME_MAX)
+				new_level++;
 		} else if (strlencmp(cmd, "down") == 0) {
-			if (mute)
+			if (new_mute)
 				new_mute = 0;
-			else
-				new_level = level == 0 ? 0 : level - 1;
-		} else if (sscanf(cmd, "level %d", &new_level) == 1 &&
-			   new_level >= 0 && new_level <= 15) {
-			/* new_level set */
+			else if (new_level > 0)
+				new_level--;
+		} else if (sscanf(cmd, "level %u", &l) == 1 &&
+			   l >= 0 && l <= TP_EC_VOLUME_MAX) {
+				new_level = l;
 		} else if (strlencmp(cmd, "mute") == 0) {
-			new_mute = 0x40;
+			new_mute = TP_EC_AUDIO_MUTESW_MSK;
 		} else
 			return -EINVAL;
+	}
 
-		if (new_level != level) {
-			/* mute doesn't change */
-
-			cmos_cmd = (new_level > level) ?
-					TP_CMOS_VOLUME_UP : TP_CMOS_VOLUME_DOWN;
-			inc = new_level > level ? 1 : -1;
-
-			if (mute && (issue_thinkpad_cmos_command(cmos_cmd) ||
-				     !acpi_ec_write(volume_offset, level)))
-				return -EIO;
-
-			for (i = level; i != new_level; i += inc)
-				if (issue_thinkpad_cmos_command(cmos_cmd) ||
-				    !acpi_ec_write(volume_offset, i + inc))
-					return -EIO;
-
-			if (mute &&
-			    (issue_thinkpad_cmos_command(TP_CMOS_VOLUME_MUTE) ||
-			     !acpi_ec_write(volume_offset, new_level + mute))) {
-				return -EIO;
-			}
-		}
-
-		if (new_mute != mute) {
-			/* level doesn't change */
+	tpacpi_disclose_usertask("procfs volume",
+				"%smute and set level to %d\n",
+				new_mute ? "" : "un", new_level);
 
-			cmos_cmd = (new_mute) ?
-				   TP_CMOS_VOLUME_MUTE : TP_CMOS_VOLUME_UP;
+	rc = volume_set_status(new_mute | new_level);
 
-			if (issue_thinkpad_cmos_command(cmos_cmd) ||
-			    !acpi_ec_write(volume_offset, level + new_mute))
-				return -EIO;
-		}
-	}
-
-	return 0;
+	return (rc == -EINTR) ? -ERESTARTSYS : rc;
 }
 
 static struct ibm_struct volume_driver_data = {
 	.name = "volume",
 	.read = volume_read,
 	.write = volume_write,
+	.exit = volume_exit,
+	.suspend = volume_suspend,
+	.shutdown = volume_shutdown,
 };
 
 /*************************************************************************
@@ -8121,6 +8339,7 @@ static struct ibm_init_struct ibms_init[] __initdata = {
 		.data = &brightness_driver_data,
 	},
 	{
+		.init = volume_init,
 		.data = &volume_driver_data,
 	},
 	{
@@ -8186,6 +8405,11 @@ MODULE_PARM_DESC(hotkey_report_mode,
 		 "used for backwards compatibility with userspace, "
 		 "see documentation");
 
+module_param_named(volume_mode, volume_mode, uint, 0444);
+MODULE_PARM_DESC(volume_mode,
+		 "Selects volume control strategy: "
+		 "0=auto, 1=EC, 2=N/A, 3=EC+NVRAM");
+
 #define TPACPI_PARAM(feature) \
 	module_param_call(feature, set_ibm_param, NULL, NULL, 0); \
 	MODULE_PARM_DESC(feature, "Simulates thinkpad-acpi procfs command " \