diff options
author | Rander Wang <rander.wang@intel.com> | 2020-01-14 18:08:43 -0600 |
---|---|---|
committer | Vinod Koul <vkoul@kernel.org> | 2020-02-25 15:57:02 +0530 |
commit | 0231453bc08f63584545dda1c05d61b19755d3a9 (patch) | |
tree | eec3badb354b05a8f6817fae89f6773a2369dd46 /drivers/soundwire/bus.c | |
parent | aa79293517b395c6094a382779c911689e8c9a8b (diff) |
soundwire: bus: add clock stop helpers
SoundWire supports two clock stop modes. Add support to handle the
clock stop modes and add pm_runtime calls in the bus.
Credits: this patch is based on an earlier internal contribution by
Vinod Koul, Sanyog Kale, Shreyas Nc and Hardik Shah.
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200115000844.14695-10-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/soundwire/bus.c')
-rw-r--r-- | drivers/soundwire/bus.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 23bc24c8e9d1..3395abd2ed39 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -2,6 +2,7 @@ // Copyright(c) 2015-17 Intel Corporation. #include <linux/acpi.h> +#include <linux/delay.h> #include <linux/mod_devicetable.h> #include <linux/pm_runtime.h> #include <linux/soundwire/sdw_registers.h> @@ -359,6 +360,52 @@ static int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value) return sdw_nwrite_no_pm(slave, addr, 1, &value); } +static int +sdw_bread_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr) +{ + struct sdw_msg msg; + u8 buf; + int ret; + + ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num, + SDW_MSG_FLAG_READ, &buf); + if (ret) + return ret; + + ret = sdw_transfer(bus, &msg); + if (ret < 0) + return ret; + else + return buf; +} + +static int +sdw_bwrite_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value) +{ + struct sdw_msg msg; + int ret; + + ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num, + SDW_MSG_FLAG_WRITE, &value); + if (ret) + return ret; + + return sdw_transfer(bus, &msg); +} + +static int +sdw_read_no_pm(struct sdw_slave *slave, u32 addr) +{ + u8 buf; + int ret; + + ret = sdw_nread_no_pm(slave, addr, 1, &buf); + if (ret < 0) + return ret; + else + return buf; +} + /** * sdw_nread() - Read "n" contiguous SDW Slave registers * @slave: SDW Slave @@ -673,6 +720,291 @@ static void sdw_modify_slave_status(struct sdw_slave *slave, mutex_unlock(&slave->bus->bus_lock); } +static enum sdw_clk_stop_mode sdw_get_clk_stop_mode(struct sdw_slave *slave) +{ + enum sdw_clk_stop_mode mode; + + /* + * Query for clock stop mode if Slave implements + * ops->get_clk_stop_mode, else read from property. + */ + if (slave->ops && slave->ops->get_clk_stop_mode) { + mode = slave->ops->get_clk_stop_mode(slave); + } else { + if (slave->prop.clk_stop_mode1) + mode = SDW_CLK_STOP_MODE1; + else + mode = SDW_CLK_STOP_MODE0; + } + + return mode; +} + +static int sdw_slave_clk_stop_callback(struct sdw_slave *slave, + enum sdw_clk_stop_mode mode, + enum sdw_clk_stop_type type) +{ + int ret; + + if (slave->ops && slave->ops->clk_stop) { + ret = slave->ops->clk_stop(slave, mode, type); + if (ret < 0) { + dev_err(&slave->dev, + "Clk Stop type =%d failed: %d\n", type, ret); + return ret; + } + } + + return 0; +} + +static int sdw_slave_clk_stop_prepare(struct sdw_slave *slave, + enum sdw_clk_stop_mode mode, + bool prepare) +{ + bool wake_en; + u32 val = 0; + int ret; + + wake_en = slave->prop.wake_capable; + + if (prepare) { + val = SDW_SCP_SYSTEMCTRL_CLK_STP_PREP; + + if (mode == SDW_CLK_STOP_MODE1) + val |= SDW_SCP_SYSTEMCTRL_CLK_STP_MODE1; + + if (wake_en) + val |= SDW_SCP_SYSTEMCTRL_WAKE_UP_EN; + } else { + val = sdw_read_no_pm(slave, SDW_SCP_SYSTEMCTRL); + + val &= ~(SDW_SCP_SYSTEMCTRL_CLK_STP_PREP); + } + + ret = sdw_write_no_pm(slave, SDW_SCP_SYSTEMCTRL, val); + + if (ret != 0) + dev_err(&slave->dev, + "Clock Stop prepare failed for slave: %d", ret); + + return ret; +} + +static int sdw_bus_wait_for_clk_prep_deprep(struct sdw_bus *bus, u16 dev_num) +{ + int retry = bus->clk_stop_timeout; + int val; + + do { + val = sdw_bread_no_pm(bus, dev_num, SDW_SCP_STAT) & + SDW_SCP_STAT_CLK_STP_NF; + if (!val) { + dev_info(bus->dev, "clock stop prep/de-prep done slave:%d", + dev_num); + return 0; + } + + usleep_range(1000, 1500); + retry--; + } while (retry); + + dev_err(bus->dev, "clock stop prep/de-prep failed slave:%d", + dev_num); + + return -ETIMEDOUT; +} + +/** + * sdw_bus_prep_clk_stop: prepare Slave(s) for clock stop + * + * @bus: SDW bus instance + * + * Query Slave for clock stop mode and prepare for that mode. + */ +int sdw_bus_prep_clk_stop(struct sdw_bus *bus) +{ + enum sdw_clk_stop_mode slave_mode; + bool simple_clk_stop = true; + struct sdw_slave *slave; + bool is_slave = false; + int ret = 0; + + /* + * In order to save on transition time, prepare + * each Slave and then wait for all Slave(s) to be + * prepared for clock stop. + */ + list_for_each_entry(slave, &bus->slaves, node) { + if (!slave->dev_num) + continue; + + /* Identify if Slave(s) are available on Bus */ + is_slave = true; + + if (slave->status != SDW_SLAVE_ATTACHED && + slave->status != SDW_SLAVE_ALERT) + continue; + + slave_mode = sdw_get_clk_stop_mode(slave); + slave->curr_clk_stop_mode = slave_mode; + + ret = sdw_slave_clk_stop_callback(slave, slave_mode, + SDW_CLK_PRE_PREPARE); + if (ret < 0) { + dev_err(&slave->dev, + "pre-prepare failed:%d", ret); + return ret; + } + + ret = sdw_slave_clk_stop_prepare(slave, + slave_mode, true); + if (ret < 0) { + dev_err(&slave->dev, + "pre-prepare failed:%d", ret); + return ret; + } + + if (slave_mode == SDW_CLK_STOP_MODE1) + simple_clk_stop = false; + } + + if (is_slave && !simple_clk_stop) { + ret = sdw_bus_wait_for_clk_prep_deprep(bus, + SDW_BROADCAST_DEV_NUM); + if (ret < 0) + return ret; + } + + /* Inform slaves that prep is done */ + list_for_each_entry(slave, &bus->slaves, node) { + if (!slave->dev_num) + continue; + + if (slave->status != SDW_SLAVE_ATTACHED && + slave->status != SDW_SLAVE_ALERT) + continue; + + slave_mode = slave->curr_clk_stop_mode; + + if (slave_mode == SDW_CLK_STOP_MODE1) { + ret = sdw_slave_clk_stop_callback(slave, + slave_mode, + SDW_CLK_POST_PREPARE); + + if (ret < 0) { + dev_err(&slave->dev, + "post-prepare failed:%d", ret); + } + } + } + + return ret; +} +EXPORT_SYMBOL(sdw_bus_prep_clk_stop); + +/** + * sdw_bus_clk_stop: stop bus clock + * + * @bus: SDW bus instance + * + * After preparing the Slaves for clock stop, stop the clock by broadcasting + * write to SCP_CTRL register. + */ +int sdw_bus_clk_stop(struct sdw_bus *bus) +{ + int ret; + + /* + * broadcast clock stop now, attached Slaves will ACK this, + * unattached will ignore + */ + ret = sdw_bwrite_no_pm(bus, SDW_BROADCAST_DEV_NUM, + SDW_SCP_CTRL, SDW_SCP_CTRL_CLK_STP_NOW); + if (ret < 0) { + dev_err(bus->dev, + "ClockStopNow Broadcast message failed %d", ret); + return ret; + } + + return 0; +} +EXPORT_SYMBOL(sdw_bus_clk_stop); + +/** + * sdw_bus_exit_clk_stop: Exit clock stop mode + * + * @bus: SDW bus instance + * + * This De-prepares the Slaves by exiting Clock Stop Mode 0. For the Slaves + * exiting Clock Stop Mode 1, they will be de-prepared after they enumerate + * back. + */ +int sdw_bus_exit_clk_stop(struct sdw_bus *bus) +{ + enum sdw_clk_stop_mode mode; + bool simple_clk_stop = true; + struct sdw_slave *slave; + bool is_slave = false; + int ret; + + /* + * In order to save on transition time, de-prepare + * each Slave and then wait for all Slave(s) to be + * de-prepared after clock resume. + */ + list_for_each_entry(slave, &bus->slaves, node) { + if (!slave->dev_num) + continue; + + /* Identify if Slave(s) are available on Bus */ + is_slave = true; + + if (slave->status != SDW_SLAVE_ATTACHED && + slave->status != SDW_SLAVE_ALERT) + continue; + + mode = slave->curr_clk_stop_mode; + + if (mode == SDW_CLK_STOP_MODE1) { + simple_clk_stop = false; + continue; + } + + ret = sdw_slave_clk_stop_callback(slave, mode, + SDW_CLK_PRE_DEPREPARE); + if (ret < 0) + dev_warn(&slave->dev, + "clk stop deprep failed:%d", ret); + + ret = sdw_slave_clk_stop_prepare(slave, mode, + false); + + if (ret < 0) + dev_warn(&slave->dev, + "clk stop deprep failed:%d", ret); + } + + if (is_slave && !simple_clk_stop) + sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM); + + list_for_each_entry(slave, &bus->slaves, node) { + if (!slave->dev_num) + continue; + + if (slave->status != SDW_SLAVE_ATTACHED && + slave->status != SDW_SLAVE_ALERT) + continue; + + mode = slave->curr_clk_stop_mode; + sdw_slave_clk_stop_callback(slave, mode, + SDW_CLK_POST_DEPREPARE); + } + + return 0; +} +EXPORT_SYMBOL(sdw_bus_exit_clk_stop); + int sdw_configure_dpn_intr(struct sdw_slave *slave, int port, bool enable, int mask) { |