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Subject[PATCH 4/6] soundwire: intel: Add basic power management support
Date
Implement suspend/resume capabilities (not runtime_pm for now)

Credits: this patch is based on an earlier internal contribution by
Vinod Koul, Sanyog Kale, Shreyas Nc and Hardik Shah.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
drivers/soundwire/cadence_master.c | 18 ++--
drivers/soundwire/cadence_master.h | 2 +-
drivers/soundwire/intel.c | 128 ++++++++++++++++++++++++++++-
3 files changed, 140 insertions(+), 8 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index bd58d80ff636..fdf9eec7cde1 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -823,14 +823,17 @@ EXPORT_SYMBOL(sdw_cdns_exit_reset);
* sdw_cdns_enable_interrupt() - Enable SDW interrupts and update config
* @cdns: Cadence instance
*/
-int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns)
+int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns, bool state)
{
- u32 mask;
+ u32 slave_intmask0 = 0;
+ u32 slave_intmask1 = 0;
+ u32 mask = 0;
+
+ if (!state)
+ goto update_masks;

- cdns_writel(cdns, CDNS_MCP_SLAVE_INTMASK0,
- CDNS_MCP_SLAVE_INTMASK0_MASK);
- cdns_writel(cdns, CDNS_MCP_SLAVE_INTMASK1,
- CDNS_MCP_SLAVE_INTMASK1_MASK);
+ slave_intmask0 = CDNS_MCP_SLAVE_INTMASK0_MASK;
+ slave_intmask1 = CDNS_MCP_SLAVE_INTMASK1_MASK;

/* enable detection of all slave state changes */
mask = CDNS_MCP_INT_SLAVE_MASK;
@@ -853,6 +856,9 @@ int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns)
if (interrupt_mask) /* parameter override */
mask = interrupt_mask;

+update_masks:
+ cdns_writel(cdns, CDNS_MCP_SLAVE_INTMASK0, slave_intmask0);
+ cdns_writel(cdns, CDNS_MCP_SLAVE_INTMASK1, slave_intmask1);
cdns_writel(cdns, CDNS_MCP_INTMASK, mask);

/* commit changes */
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index 1a67728c5000..302351808098 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -162,7 +162,7 @@ int sdw_cdns_init(struct sdw_cdns *cdns);
int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
struct sdw_cdns_stream_config config);
int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
-int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns);
+int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns, bool state);

#ifdef CONFIG_DEBUG_FS
void sdw_cdns_debugfs_init(struct sdw_cdns *cdns, struct dentry *root);
diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 3d22c9023a9b..42bdc870c3ee 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -12,6 +12,7 @@
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <sound/pcm_params.h>
+#include <linux/pm_runtime.h>
#include <sound/soc.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
@@ -284,6 +285,35 @@ static void intel_debugfs_exit(struct sdw_intel *sdw) {}
/*
* shim ops
*/
+static int intel_link_power_down(struct sdw_intel *sdw)
+{
+ int link_control, spa_mask, cpa_mask, ret;
+ unsigned int link_id = sdw->instance;
+ void __iomem *shim = sdw->res->shim;
+ u16 ioctl;
+
+ /* Glue logic */
+ ioctl = intel_readw(shim, SDW_SHIM_IOCTL(link_id));
+ ioctl |= SDW_SHIM_IOCTL_BKE;
+ ioctl |= SDW_SHIM_IOCTL_COE;
+ intel_writew(shim, SDW_SHIM_IOCTL(link_id), ioctl);
+
+ ioctl &= ~(SDW_SHIM_IOCTL_MIF);
+ intel_writew(shim, SDW_SHIM_IOCTL(link_id), ioctl);
+
+ /* Link power down sequence */
+ link_control = intel_readl(shim, SDW_SHIM_LCTL);
+ spa_mask = ~(SDW_SHIM_LCTL_SPA << link_id);
+ cpa_mask = (SDW_SHIM_LCTL_CPA << link_id);
+ link_control &= spa_mask;
+
+ ret = intel_clear_bit(shim, SDW_SHIM_LCTL, link_control, cpa_mask);
+ if (ret < 0)
+ return ret;
+
+ sdw->cdns.link_up = false;
+ return 0;
+}

static int intel_link_power_up(struct sdw_intel *sdw)
{
@@ -306,6 +336,29 @@ static int intel_link_power_up(struct sdw_intel *sdw)
return 0;
}

+static void intel_shim_wake(struct sdw_intel *sdw, bool wake_enable)
+{
+ void __iomem *shim = sdw->res->shim;
+ unsigned int link_id = sdw->instance;
+ u16 wake_en, wake_sts;
+
+ if (wake_enable) {
+ /* Enable the wakeup */
+ intel_writew(shim, SDW_SHIM_WAKEEN,
+ (SDW_SHIM_WAKEEN_ENABLE << link_id));
+ } else {
+ /* Disable the wake up interrupt */
+ wake_en = intel_readw(shim, SDW_SHIM_WAKEEN);
+ wake_en &= ~(SDW_SHIM_WAKEEN_ENABLE << link_id);
+ intel_writew(shim, SDW_SHIM_WAKEEN, wake_en);
+
+ /* Clear wake status */
+ wake_sts = intel_readw(shim, SDW_SHIM_WAKESTS);
+ wake_sts |= (SDW_SHIM_WAKEEN_ENABLE << link_id);
+ intel_writew(shim, SDW_SHIM_WAKESTS_STATUS, wake_sts);
+ }
+}
+
static int intel_shim_init(struct sdw_intel *sdw)
{
void __iomem *shim = sdw->res->shim;
@@ -1066,7 +1119,7 @@ static int intel_probe(struct platform_device *pdev)
goto err_init;
}

- ret = sdw_cdns_enable_interrupt(&sdw->cdns);
+ ret = sdw_cdns_enable_interrupt(&sdw->cdns, true);
if (ret < 0) {
dev_err(sdw->cdns.dev, "cannot enable interrupts\n");
goto err_init;
@@ -1114,11 +1167,84 @@ static int intel_remove(struct platform_device *pdev)
return 0;
}

+/*
+ * PM calls
+ */
+
+#ifdef CONFIG_PM
+
+static int intel_suspend(struct device *dev)
+{
+ struct sdw_intel *sdw = dev_get_drvdata(dev);
+ int ret;
+
+ if (sdw->cdns.bus.prop.hw_disabled) {
+ dev_dbg(dev, "SoundWire master %d is disabled, ignoring\n",
+ sdw->cdns.bus.link_id);
+ return 0;
+ }
+
+ ret = sdw_cdns_enable_interrupt(&sdw->cdns, false);
+ if (ret < 0) {
+ dev_err(sdw->cdns.dev, "cannot disable interrupts on suspend\n");
+ return ret;
+ }
+
+ ret = intel_link_power_down(sdw);
+ if (ret) {
+ dev_err(dev, "Link power down failed: %d", ret);
+ return ret;
+ }
+
+ intel_shim_wake(sdw, false);
+
+ return 0;
+}
+
+static int intel_resume(struct device *dev)
+{
+ struct sdw_intel *sdw = dev_get_drvdata(dev);
+ int ret;
+
+ if (sdw->cdns.bus.prop.hw_disabled) {
+ dev_dbg(dev, "SoundWire master %d is disabled, ignoring\n",
+ sdw->cdns.bus.link_id);
+ return 0;
+ }
+
+ ret = intel_init(sdw);
+ if (ret) {
+ dev_err(dev, "%s failed: %d", __func__, ret);
+ return ret;
+ }
+
+ ret = sdw_cdns_enable_interrupt(&sdw->cdns, true);
+ if (ret < 0) {
+ dev_err(sdw->cdns.dev, "cannot enable interrupts during resume\n");
+ return ret;
+ }
+
+ ret = sdw_cdns_exit_reset(&sdw->cdns);
+ if (ret < 0) {
+ dev_err(sdw->cdns.dev, "unable to exit bus reset sequence during resume\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+#endif
+
+static const struct dev_pm_ops intel_pm = {
+ SET_SYSTEM_SLEEP_PM_OPS(intel_suspend, intel_resume)
+};
+
static struct platform_driver sdw_intel_drv = {
.probe = intel_probe,
.remove = intel_remove,
.driver = {
.name = "int-sdw",
+ .pm = &intel_pm,

},
};
--
2.20.1
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