soc: ti: pruss: Configure SYSCFG properly during probe/remove

The PRUSS CFG module's SYSCFG register is used for managing the
PRCM clock management settings at the PRU-ICSS subsystem level.

Add two helper functions pruss_{enable/disable}_module() that
programs this SYSCFG register during probe and remove. The
register is currently programmed for the default Smart-Idle
and Smart-Standby always during probe. The MStandby is enabled
during remove to undo the settings in probe to properly configure
the SYSCFG in the case that a firmware has disabled MStandby.
This is needed on SoCs like AM57xx that do not have a reset line
and so cannot reset the register properly.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>

diff --git a/drivers/soc/ti/pruss_soc_bus.c b/drivers/soc/ti/pruss_soc_bus.c
index afa55c9c9d94c201f9d5e1a9d50142ee0af0794e..ff1e0d0f59efed3ae75e2fff94c39061242bc04d 100644 (file)
--- a/drivers/soc/ti/pruss_soc_bus.c
+++ b/drivers/soc/ti/pruss_soc_bus.c
@@ -20,6 +20,16 @@
 #define SYSCFG_STANDBY_INIT    BIT(4)
 #define SYSCFG_SUB_MWAIT_READY BIT(5)
 
+#define SYSCFG_STANDBY_MODE_FORCE      (0 << 2)
+#define SYSCFG_STANDBY_MODE_NO         (1 << 2)
+#define SYSCFG_STANDBY_MODE_SMART      (2 << 2)
+#define SYSCFG_STANDBY_MODE_MASK       (3 << 2)
+
+#define SYSCFG_IDLE_MODE_FORCE         0
+#define SYSCFG_IDLE_MODE_NO            1
+#define SYSCFG_IDLE_MODE_SMART         2
+#define SYSCFG_IDLE_MODE_MASK          3
+
 /**
  * struct pruss_soc_bus - PRUSS SoC bus structure
  * @syscfg: kernel mapped address for SYSCFG register
@@ -115,6 +125,44 @@ static int __maybe_unused pruss_soc_bus_resume(struct device *dev)
        return ret;
 }
 
+/* firmware must be idle when calling this function */
+static void pruss_disable_module(struct device *dev)
+{
+       struct pruss_soc_bus *psoc_bus = dev_get_drvdata(dev);
+
+       /* configure Smart Standby */
+       pruss_soc_bus_rmw(psoc_bus->syscfg, SYSCFG_STANDBY_MODE_MASK,
+                         SYSCFG_STANDBY_MODE_SMART);
+
+       /* initiate MStandby */
+       pruss_soc_bus_rmw(psoc_bus->syscfg, SYSCFG_STANDBY_INIT,
+                         SYSCFG_STANDBY_INIT);
+
+       /* tell PRCM to initiate IDLE request */
+       pm_runtime_put_sync(dev);
+}
+
+static int pruss_enable_module(struct device *dev)
+{
+       struct pruss_soc_bus *psoc_bus = dev_get_drvdata(dev);
+       int ret;
+
+       /* tell PRCM to de-assert IDLE request */
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0) {
+               pm_runtime_put_noidle(dev);
+               return ret;
+       }
+
+       /* configure for Smart Idle & Smart Standby */
+       pruss_soc_bus_rmw(psoc_bus->syscfg, SYSCFG_IDLE_MODE_MASK,
+                         SYSCFG_IDLE_MODE_SMART);
+       pruss_soc_bus_rmw(psoc_bus->syscfg, SYSCFG_STANDBY_MODE_MASK,
+                         SYSCFG_STANDBY_MODE_SMART);
+
+       return ret;
+}
+
 static int pruss_soc_bus_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
@@ -155,10 +203,10 @@ static int pruss_soc_bus_probe(struct platform_device *pdev)
        }
 
        pm_runtime_enable(dev);
-       ret = pm_runtime_get_sync(dev);
+       ret = pruss_enable_module(dev);
        if (ret < 0) {
-               pm_runtime_put_noidle(dev);
-               goto fail_clock;
+               dev_err(dev, "couldn't enable module\n");
+               goto fail_module;
        }
 
        ret = of_platform_populate(node, NULL, NULL, dev);
@@ -168,8 +216,8 @@ static int pruss_soc_bus_probe(struct platform_device *pdev)
        return 0;
 
 fail_of:
-       pm_runtime_put_sync(dev);
-fail_clock:
+       pruss_disable_module(dev);
+fail_module:
        pm_runtime_disable(dev);
        if (psoc_bus->has_reset)
                pdata->assert_reset(pdev, pdata->reset_name);
@@ -186,7 +234,7 @@ static int pruss_soc_bus_remove(struct platform_device *pdev)
 
        of_platform_depopulate(dev);
 
-       pm_runtime_put_sync(dev);
+       pruss_disable_module(dev);
        pm_runtime_disable(dev);
 
        if (psoc_bus->has_reset)