Message ID | 1512122177-2889-9-git-send-email-vinod.koul@intel.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On 12/1/17 3:56 AM, Vinod Koul wrote: > From: Sanyog Kale <sanyog.r.kale@intel.com> > > SoundWire Slaves report status to bus. Add helpers to handle > the status changes. > > Signed-off-by: Hardik T Shah <hardik.t.shah@intel.com> > Signed-off-by: Sanyog Kale <sanyog.r.kale@intel.com> > Signed-off-by: Vinod Koul <vinod.koul@intel.com> > --- > drivers/soundwire/bus.c | 202 ++++++++++++++++++++++++++++++++++++++++++ > drivers/soundwire/bus.h | 14 +++ > include/linux/soundwire/sdw.h | 1 + > 3 files changed, 217 insertions(+) > > diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c > index 2f108f162905..09126ddd3cdd 100644 > --- a/drivers/soundwire/bus.c > +++ b/drivers/soundwire/bus.c > @@ -372,6 +372,93 @@ int sdw_write(struct sdw_slave *slave, u32 addr, u8 value) > } > EXPORT_SYMBOL(sdw_write); > > +/* > + * SDW alert handling > + */ > + > +/* called with bus_lock held */ > +static struct sdw_slave *sdw_get_slave(struct sdw_bus *bus, int i) > +{ > + struct sdw_slave *slave = NULL; > + > + list_for_each_entry(slave, &bus->slaves, node) { > + if (slave->dev_num == i) > + return slave; > + } > + > + return NULL; > +} > + > +static int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id) > +{ > + > + if ((slave->id.unique_id != id.unique_id) || > + (slave->id.mfg_id != id.mfg_id) || > + (slave->id.part_id != id.part_id) || > + (slave->id.class_id != id.class_id)) > + return -ENODEV; > + > + return 0; > +} > + > +/* called with bus_lock held */ > +static int sdw_get_device_num(struct sdw_slave *slave) > +{ > + int bit; > + > + bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); > + if (bit == SDW_MAX_DEVICES) { > + bit = -ENODEV; > + goto err; My brain is starting to fry but is this correct? Bit11 seems like a valid value. Should it be bit > 15 (assuming bit 12,13,14 are set to avoid using groups and master)? > + } > + > + /* > + * Do not update dev_num in Slave data structure here, > + * Update once program dev_num is successful > + */ > + set_bit(bit, slave->bus->assigned); > + > +err: > + return bit; > +} > + > +static int sdw_assign_device_num(struct sdw_slave *slave) > +{ > + int ret, dev_num; > + > + /* check first if device number is assigned, if so reuse that */ > + if (!slave->dev_num) { > + mutex_lock(&slave->bus->bus_lock); > + dev_num = sdw_get_device_num(slave); > + mutex_unlock(&slave->bus->bus_lock); > + if (dev_num < 0) { > + dev_err(slave->bus->dev, "Get dev_num failed: %d", > + dev_num); > + return dev_num; > + } > + } else { > + dev_info(slave->bus->dev, > + "Slave already registered dev_num:%d", > + slave->dev_num); > + > + /* Clear the slave->dev_num to transfer message on device 0 */ > + dev_num = slave->dev_num; > + slave->dev_num = 0; > + > + } > + > + ret = sdw_write(slave, SDW_SCP_DEVNUMBER, dev_num); > + if (ret < 0) { > + dev_err(&slave->dev, "Program device_num failed: %d", ret); > + return ret; > + } > + > + /* After xfer of msg, restore dev_num */ > + slave->dev_num = dev_num; > + > + return 0; > +} > + > void sdw_extract_slave_id(struct sdw_bus *bus, > u64 addr, struct sdw_slave_id *id) > { > @@ -400,3 +487,118 @@ void sdw_extract_slave_id(struct sdw_bus *bus, > id->unique_id, id->sdw_version); > > } > + > +static int sdw_program_device_num(struct sdw_bus *bus) > +{ > + u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0}; > + struct sdw_slave *slave, *_s; > + struct sdw_slave_id id; > + struct sdw_msg msg; > + bool found = false; > + int count = 0, ret; > + u64 addr; > + > + /* No Slave, so use raw xfer api */ > + ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0, > + SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf); > + if (ret < 0) > + return ret; > + > + do { > + ret = sdw_transfer(bus, NULL, &msg); > + if (ret == -ENODATA) { /* end of device id reads */ > + ret = 0; > + break; > + } > + if (ret < 0) { > + dev_err(bus->dev, "DEVID read fail:%d\n", ret); > + break; > + } > + > + /* > + * Construct the addr and extract. Cast the higher shift > + * bits to avoid truncation due to size limit. > + */ > + addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) | > + (buf[2] << 24) | ((unsigned long long)buf[1] << 32) | > + ((unsigned long long)buf[0] << 40); > + > + sdw_extract_slave_id(bus, addr, &id); > + > + /* Now compare with entries */ > + list_for_each_entry_safe(slave, _s, &bus->slaves, node) { > + if (sdw_compare_devid(slave, id) == 0) { > + found = true; > + > + /* > + * Assign a new dev_num to this Slave and > + * not mark it present. It will be marked > + * present after it reports ATTACHED on new > + * dev_num > + */ > + ret = sdw_assign_device_num(slave); > + if (ret) { > + dev_err(slave->bus->dev, > + "Assign dev_num failed:%d", > + ret); > + return ret; > + } > + > + break; > + } > + } > + > + if (found == false) { > + /* TODO: Park this device in Group 13 */ > + dev_err(bus->dev, "Slave Entry not found"); > + } > + > + count++; > + > + } while (ret == 0 && count < (SDW_MAX_DEVICES * 2)); explain that the last condition is intentional - this is not a bug -, some devices can drop off during enumeration and rejoin so might be counted twice. > + > + return ret; > +} > + > +static void sdw_modify_slave_status(struct sdw_slave *slave, > + enum sdw_slave_status status) > +{ > + mutex_lock(&slave->bus->bus_lock); > + slave->status = status; > + mutex_unlock(&slave->bus->bus_lock); > +} > + > +static int sdw_initialize_slave(struct sdw_slave *slave) > +{ > + struct sdw_slave_prop *prop = &slave->prop; > + int ret; > + u8 val; > + > + /* Set bus clash and parity interrupt mask */ > + val = SDW_SCP_INT1_BUS_CLASH | SDW_SCP_INT1_PARITY; > + > + /* Enable SCP interrupts */ > + ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val); > + if (ret < 0) { > + dev_err(slave->bus->dev, > + "SDW_SCP_INTMASK1 write failed:%d", ret); > + return ret; > + } > + > + /* No need to continue if DP0 is not present */ > + if (!slave->prop.dp0_prop) > + return 0; > + > + /* Enable DP0 interrupts */ > + val = prop->dp0_prop->device_interrupts; > + val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE; > + > + ret = sdw_update(slave, SDW_DP0_INTMASK, val, val); > + if (ret < 0) { > + dev_err(slave->bus->dev, > + "SDW_DP0_INTMASK read failed:%d", ret); > + return val; > + } > + > + return 0; > +} > diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h > index bde5f840ca96..b491e86f2c4c 100644 > --- a/drivers/soundwire/bus.h > +++ b/drivers/soundwire/bus.h > @@ -53,4 +53,18 @@ int sdw_transfer_defer(struct sdw_bus *bus, struct sdw_slave *slave, > int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave, > u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf); > > +/* Read-Modify-Write Slave register */ > +static inline int > +sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val) > +{ > + int tmp; > + > + tmp = sdw_read(slave, addr); > + if (tmp < 0) > + return tmp; > + > + tmp = (tmp & ~mask) | val; > + return sdw_write(slave, addr, tmp); > +} > + > #endif /* __SDW_BUS_H */ > diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h > index d3337b5b882b..09619d042909 100644 > --- a/include/linux/soundwire/sdw.h > +++ b/include/linux/soundwire/sdw.h > @@ -15,6 +15,7 @@ struct sdw_slave; > /* SDW Enumeration Device Number */ > #define SDW_ENUM_DEV_NUM 0 > > +#define SDW_NUM_DEV_ID_REGISTERS 6 > #define SDW_MAX_DEVICES 11 > > /** >
On Fri, Dec 01, 2017 at 05:36:47PM -0600, Pierre-Louis Bossart wrote: > >+/* called with bus_lock held */ > >+static int sdw_get_device_num(struct sdw_slave *slave) > >+{ > >+ int bit; > >+ > >+ bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); > >+ if (bit == SDW_MAX_DEVICES) { > >+ bit = -ENODEV; > >+ goto err; > > My brain is starting to fry but is this correct? Bit11 seems like a valid > value. Should it be bit > 15 (assuming bit 12,13,14 are set to avoid using > groups and master)? this is correct. You are confusing SDW concept and API return types! That should be hint for you to start weekend if you didn't do so :D This API returns max value it was provided (last arg) if it doesn't find free bit. That's an indication to caller that we ran out of devices hence ENODEV error! > >+static int sdw_program_device_num(struct sdw_bus *bus) > >+{ > >+ u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0}; > >+ struct sdw_slave *slave, *_s; > >+ struct sdw_slave_id id; > >+ struct sdw_msg msg; > >+ bool found = false; > >+ int count = 0, ret; > >+ u64 addr; > >+ > >+ /* No Slave, so use raw xfer api */ > >+ ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0, > >+ SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf); > >+ if (ret < 0) > >+ return ret; > >+ > >+ do { > >+ ret = sdw_transfer(bus, NULL, &msg); > >+ if (ret == -ENODATA) { /* end of device id reads */ > >+ ret = 0; > >+ break; > >+ } > >+ if (ret < 0) { > >+ dev_err(bus->dev, "DEVID read fail:%d\n", ret); > >+ break; > >+ } > >+ > >+ /* > >+ * Construct the addr and extract. Cast the higher shift > >+ * bits to avoid truncation due to size limit. > >+ */ > >+ addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) | > >+ (buf[2] << 24) | ((unsigned long long)buf[1] << 32) | > >+ ((unsigned long long)buf[0] << 40); > >+ > >+ sdw_extract_slave_id(bus, addr, &id); > >+ > >+ /* Now compare with entries */ > >+ list_for_each_entry_safe(slave, _s, &bus->slaves, node) { > >+ if (sdw_compare_devid(slave, id) == 0) { > >+ found = true; > >+ > >+ /* > >+ * Assign a new dev_num to this Slave and > >+ * not mark it present. It will be marked > >+ * present after it reports ATTACHED on new > >+ * dev_num > >+ */ > >+ ret = sdw_assign_device_num(slave); > >+ if (ret) { > >+ dev_err(slave->bus->dev, > >+ "Assign dev_num failed:%d", > >+ ret); > >+ return ret; > >+ } > >+ > >+ break; > >+ } > >+ } > >+ > >+ if (found == false) { > >+ /* TODO: Park this device in Group 13 */ > >+ dev_err(bus->dev, "Slave Entry not found"); > >+ } > >+ > >+ count++; > >+ > >+ } while (ret == 0 && count < (SDW_MAX_DEVICES * 2)); > > explain that the last condition is intentional - this is not a bug -, some > devices can drop off during enumeration and rejoin so might be counted > twice. ok will add
On 12/3/17 11:08 AM, Vinod Koul wrote: > On Fri, Dec 01, 2017 at 05:36:47PM -0600, Pierre-Louis Bossart wrote: > >>> +/* called with bus_lock held */ >>> +static int sdw_get_device_num(struct sdw_slave *slave) >>> +{ >>> + int bit; >>> + >>> + bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); >>> + if (bit == SDW_MAX_DEVICES) { >>> + bit = -ENODEV; >>> + goto err; >> >> My brain is starting to fry but is this correct? Bit11 seems like a valid >> value. Should it be bit > 15 (assuming bit 12,13,14 are set to avoid using >> groups and master)? > > this is correct. You are confusing SDW concept and API return types! > That should be hint for you to start weekend if you didn't do so :D > > This API returns max value it was provided (last arg) if it doesn't > find free bit. That's an indication to caller that we ran out of devices > hence ENODEV error! Can you just make sure bit11 is included? > >>> +static int sdw_program_device_num(struct sdw_bus *bus) >>> +{ >>> + u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0}; >>> + struct sdw_slave *slave, *_s; >>> + struct sdw_slave_id id; >>> + struct sdw_msg msg; >>> + bool found = false; >>> + int count = 0, ret; >>> + u64 addr; >>> + >>> + /* No Slave, so use raw xfer api */ >>> + ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0, >>> + SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf); >>> + if (ret < 0) >>> + return ret; >>> + >>> + do { >>> + ret = sdw_transfer(bus, NULL, &msg); >>> + if (ret == -ENODATA) { /* end of device id reads */ >>> + ret = 0; >>> + break; >>> + } >>> + if (ret < 0) { >>> + dev_err(bus->dev, "DEVID read fail:%d\n", ret); >>> + break; >>> + } >>> + >>> + /* >>> + * Construct the addr and extract. Cast the higher shift >>> + * bits to avoid truncation due to size limit. >>> + */ >>> + addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) | >>> + (buf[2] << 24) | ((unsigned long long)buf[1] << 32) | >>> + ((unsigned long long)buf[0] << 40); >>> + >>> + sdw_extract_slave_id(bus, addr, &id); >>> + >>> + /* Now compare with entries */ >>> + list_for_each_entry_safe(slave, _s, &bus->slaves, node) { >>> + if (sdw_compare_devid(slave, id) == 0) { >>> + found = true; >>> + >>> + /* >>> + * Assign a new dev_num to this Slave and >>> + * not mark it present. It will be marked >>> + * present after it reports ATTACHED on new >>> + * dev_num >>> + */ >>> + ret = sdw_assign_device_num(slave); >>> + if (ret) { >>> + dev_err(slave->bus->dev, >>> + "Assign dev_num failed:%d", >>> + ret); >>> + return ret; >>> + } >>> + >>> + break; >>> + } >>> + } >>> + >>> + if (found == false) { >>> + /* TODO: Park this device in Group 13 */ >>> + dev_err(bus->dev, "Slave Entry not found"); >>> + } >>> + >>> + count++; >>> + >>> + } while (ret == 0 && count < (SDW_MAX_DEVICES * 2)); >> >> explain that the last condition is intentional - this is not a bug -, some >> devices can drop off during enumeration and rejoin so might be counted >> twice. > > ok will add >
On Sun, Dec 03, 2017 at 09:07:29PM -0600, Pierre-Louis Bossart wrote: > On 12/3/17 11:08 AM, Vinod Koul wrote: > >On Fri, Dec 01, 2017 at 05:36:47PM -0600, Pierre-Louis Bossart wrote: > > > >>>+/* called with bus_lock held */ > >>>+static int sdw_get_device_num(struct sdw_slave *slave) > >>>+{ > >>>+ int bit; > >>>+ > >>>+ bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); > >>>+ if (bit == SDW_MAX_DEVICES) { > >>>+ bit = -ENODEV; > >>>+ goto err; > >> > >>My brain is starting to fry but is this correct? Bit11 seems like a valid > >>value. Should it be bit > 15 (assuming bit 12,13,14 are set to avoid using > >>groups and master)? > > > >this is correct. You are confusing SDW concept and API return types! > >That should be hint for you to start weekend if you didn't do so :D > > > >This API returns max value it was provided (last arg) if it doesn't > >find free bit. That's an indication to caller that we ran out of devices > >hence ENODEV error! > > Can you just make sure bit11 is included? yes it is, refer to the masks we set for bit, only 0 and 15 and now 12,13 and 14 will be masked out. So we can get from 1 to 11 both inclusive.
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 2f108f162905..09126ddd3cdd 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -372,6 +372,93 @@ int sdw_write(struct sdw_slave *slave, u32 addr, u8 value) } EXPORT_SYMBOL(sdw_write); +/* + * SDW alert handling + */ + +/* called with bus_lock held */ +static struct sdw_slave *sdw_get_slave(struct sdw_bus *bus, int i) +{ + struct sdw_slave *slave = NULL; + + list_for_each_entry(slave, &bus->slaves, node) { + if (slave->dev_num == i) + return slave; + } + + return NULL; +} + +static int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id) +{ + + if ((slave->id.unique_id != id.unique_id) || + (slave->id.mfg_id != id.mfg_id) || + (slave->id.part_id != id.part_id) || + (slave->id.class_id != id.class_id)) + return -ENODEV; + + return 0; +} + +/* called with bus_lock held */ +static int sdw_get_device_num(struct sdw_slave *slave) +{ + int bit; + + bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); + if (bit == SDW_MAX_DEVICES) { + bit = -ENODEV; + goto err; + } + + /* + * Do not update dev_num in Slave data structure here, + * Update once program dev_num is successful + */ + set_bit(bit, slave->bus->assigned); + +err: + return bit; +} + +static int sdw_assign_device_num(struct sdw_slave *slave) +{ + int ret, dev_num; + + /* check first if device number is assigned, if so reuse that */ + if (!slave->dev_num) { + mutex_lock(&slave->bus->bus_lock); + dev_num = sdw_get_device_num(slave); + mutex_unlock(&slave->bus->bus_lock); + if (dev_num < 0) { + dev_err(slave->bus->dev, "Get dev_num failed: %d", + dev_num); + return dev_num; + } + } else { + dev_info(slave->bus->dev, + "Slave already registered dev_num:%d", + slave->dev_num); + + /* Clear the slave->dev_num to transfer message on device 0 */ + dev_num = slave->dev_num; + slave->dev_num = 0; + + } + + ret = sdw_write(slave, SDW_SCP_DEVNUMBER, dev_num); + if (ret < 0) { + dev_err(&slave->dev, "Program device_num failed: %d", ret); + return ret; + } + + /* After xfer of msg, restore dev_num */ + slave->dev_num = dev_num; + + return 0; +} + void sdw_extract_slave_id(struct sdw_bus *bus, u64 addr, struct sdw_slave_id *id) { @@ -400,3 +487,118 @@ void sdw_extract_slave_id(struct sdw_bus *bus, id->unique_id, id->sdw_version); } + +static int sdw_program_device_num(struct sdw_bus *bus) +{ + u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0}; + struct sdw_slave *slave, *_s; + struct sdw_slave_id id; + struct sdw_msg msg; + bool found = false; + int count = 0, ret; + u64 addr; + + /* No Slave, so use raw xfer api */ + ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0, + SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf); + if (ret < 0) + return ret; + + do { + ret = sdw_transfer(bus, NULL, &msg); + if (ret == -ENODATA) { /* end of device id reads */ + ret = 0; + break; + } + if (ret < 0) { + dev_err(bus->dev, "DEVID read fail:%d\n", ret); + break; + } + + /* + * Construct the addr and extract. Cast the higher shift + * bits to avoid truncation due to size limit. + */ + addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) | + (buf[2] << 24) | ((unsigned long long)buf[1] << 32) | + ((unsigned long long)buf[0] << 40); + + sdw_extract_slave_id(bus, addr, &id); + + /* Now compare with entries */ + list_for_each_entry_safe(slave, _s, &bus->slaves, node) { + if (sdw_compare_devid(slave, id) == 0) { + found = true; + + /* + * Assign a new dev_num to this Slave and + * not mark it present. It will be marked + * present after it reports ATTACHED on new + * dev_num + */ + ret = sdw_assign_device_num(slave); + if (ret) { + dev_err(slave->bus->dev, + "Assign dev_num failed:%d", + ret); + return ret; + } + + break; + } + } + + if (found == false) { + /* TODO: Park this device in Group 13 */ + dev_err(bus->dev, "Slave Entry not found"); + } + + count++; + + } while (ret == 0 && count < (SDW_MAX_DEVICES * 2)); + + return ret; +} + +static void sdw_modify_slave_status(struct sdw_slave *slave, + enum sdw_slave_status status) +{ + mutex_lock(&slave->bus->bus_lock); + slave->status = status; + mutex_unlock(&slave->bus->bus_lock); +} + +static int sdw_initialize_slave(struct sdw_slave *slave) +{ + struct sdw_slave_prop *prop = &slave->prop; + int ret; + u8 val; + + /* Set bus clash and parity interrupt mask */ + val = SDW_SCP_INT1_BUS_CLASH | SDW_SCP_INT1_PARITY; + + /* Enable SCP interrupts */ + ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val); + if (ret < 0) { + dev_err(slave->bus->dev, + "SDW_SCP_INTMASK1 write failed:%d", ret); + return ret; + } + + /* No need to continue if DP0 is not present */ + if (!slave->prop.dp0_prop) + return 0; + + /* Enable DP0 interrupts */ + val = prop->dp0_prop->device_interrupts; + val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE; + + ret = sdw_update(slave, SDW_DP0_INTMASK, val, val); + if (ret < 0) { + dev_err(slave->bus->dev, + "SDW_DP0_INTMASK read failed:%d", ret); + return val; + } + + return 0; +} diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h index bde5f840ca96..b491e86f2c4c 100644 --- a/drivers/soundwire/bus.h +++ b/drivers/soundwire/bus.h @@ -53,4 +53,18 @@ int sdw_transfer_defer(struct sdw_bus *bus, struct sdw_slave *slave, int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave, u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf); +/* Read-Modify-Write Slave register */ +static inline int +sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val) +{ + int tmp; + + tmp = sdw_read(slave, addr); + if (tmp < 0) + return tmp; + + tmp = (tmp & ~mask) | val; + return sdw_write(slave, addr, tmp); +} + #endif /* __SDW_BUS_H */ diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h index d3337b5b882b..09619d042909 100644 --- a/include/linux/soundwire/sdw.h +++ b/include/linux/soundwire/sdw.h @@ -15,6 +15,7 @@ struct sdw_slave; /* SDW Enumeration Device Number */ #define SDW_ENUM_DEV_NUM 0 +#define SDW_NUM_DEV_ID_REGISTERS 6 #define SDW_MAX_DEVICES 11 /**