[PATCH 3/9] bus: ti-sysc: Add quirk handling for reinit on context lost
Tony Lindgren
tony at atomide.com
Tue Sep 21 03:01:09 PDT 2021
Some interconnect target modules such as otg and gpmc on am335x need a
re-init after resume. As we also have PM runtime cases where the context
may be lost, let's handle these all with cpu_pm.
For the am335x resume path, we already have cpu_pm_resume() call
cpu_pm_cluster_exit().
Signed-off-by: Tony Lindgren <tony at atomide.com>
---
drivers/bus/ti-sysc.c | 108 ++++++++++++++++++++++++--
include/linux/platform_data/ti-sysc.h | 1 +
2 files changed, 103 insertions(+), 6 deletions(-)
diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -6,6 +6,7 @@
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
+#include <linux/cpu_pm.h>
#include <linux/delay.h>
#include <linux/list.h>
#include <linux/module.h>
@@ -52,11 +53,18 @@ struct sysc_address {
struct list_head node;
};
+struct sysc_module {
+ struct sysc *ddata;
+ struct list_head node;
+};
+
struct sysc_soc_info {
unsigned long general_purpose:1;
enum sysc_soc soc;
- struct mutex list_lock; /* disabled modules list lock */
+ struct mutex list_lock; /* disabled and restored modules list lock */
struct list_head disabled_modules;
+ struct list_head restored_modules;
+ struct notifier_block nb;
};
enum sysc_clocks {
@@ -2477,6 +2485,79 @@ static struct dev_pm_domain sysc_child_pm_domain = {
}
};
+/* Caller needs to take list_lock if ever used outside of cpu_pm */
+static void sysc_reinit_modules(struct sysc_soc_info *soc)
+{
+ struct sysc_module *module;
+ struct list_head *pos;
+ struct sysc *ddata;
+ int error = 0;
+
+ list_for_each(pos, &sysc_soc->restored_modules) {
+ module = list_entry(pos, struct sysc_module, node);
+ ddata = module->ddata;
+ error = sysc_reinit_module(ddata, ddata->enabled);
+ }
+}
+
+/**
+ * sysc_context_notifier - optionally reset and restore module after idle
+ * @nb: notifier block
+ * @cmd: unused
+ * @v: unused
+ *
+ * Some interconnect target modules need to be restored, or reset and restored
+ * on CPU_PM CPU_PM_CLUSTER_EXIT notifier. This is needed at least for am335x
+ * OTG and GPMC target modules even if the modules are unused.
+ */
+static int sysc_context_notifier(struct notifier_block *nb, unsigned long cmd,
+ void *v)
+{
+ struct sysc_soc_info *soc;
+
+ soc = container_of(nb, struct sysc_soc_info, nb);
+
+ switch (cmd) {
+ case CPU_CLUSTER_PM_ENTER:
+ break;
+ case CPU_CLUSTER_PM_ENTER_FAILED: /* No need to restore context */
+ break;
+ case CPU_CLUSTER_PM_EXIT:
+ sysc_reinit_modules(soc);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+/**
+ * sysc_add_restored - optionally add reset and restore quirk hanlling
+ * @ddata: device data
+ */
+static void sysc_add_restored(struct sysc *ddata)
+{
+ struct sysc_module *restored_module;
+
+ restored_module = kzalloc(sizeof(*restored_module), GFP_KERNEL);
+ if (!restored_module)
+ return;
+
+ restored_module->ddata = ddata;
+
+ mutex_lock(&sysc_soc->list_lock);
+
+ list_add(&restored_module->node, &sysc_soc->restored_modules);
+
+ if (sysc_soc->nb.notifier_call)
+ goto out_unlock;
+
+ sysc_soc->nb.notifier_call = sysc_context_notifier;
+ cpu_pm_register_notifier(&sysc_soc->nb);
+
+out_unlock:
+ mutex_unlock(&sysc_soc->list_lock);
+}
+
/**
* sysc_legacy_idle_quirk - handle children in omap_device compatible way
* @ddata: device driver data
@@ -2976,12 +3057,14 @@ static int sysc_add_disabled(unsigned long base)
}
/*
- * One time init to detect the booted SoC and disable unavailable features.
+ * One time init to detect the booted SoC, disable unavailable features
+ * and initialize list for optional cpu_pm notifier.
+ *
* Note that we initialize static data shared across all ti-sysc instances
* so ddata is only used for SoC type. This can be called from module_init
* once we no longer need to rely on platform data.
*/
-static int sysc_init_soc(struct sysc *ddata)
+static int sysc_init_static_data(struct sysc *ddata)
{
const struct soc_device_attribute *match;
struct ti_sysc_platform_data *pdata;
@@ -2997,6 +3080,7 @@ static int sysc_init_soc(struct sysc *ddata)
mutex_init(&sysc_soc->list_lock);
INIT_LIST_HEAD(&sysc_soc->disabled_modules);
+ INIT_LIST_HEAD(&sysc_soc->restored_modules);
sysc_soc->general_purpose = true;
pdata = dev_get_platdata(ddata->dev);
@@ -3060,15 +3144,24 @@ static int sysc_init_soc(struct sysc *ddata)
return 0;
}
-static void sysc_cleanup_soc(void)
+static void sysc_cleanup_static_data(void)
{
+ struct sysc_module *restored_module;
struct sysc_address *disabled_module;
struct list_head *pos, *tmp;
if (!sysc_soc)
return;
+ if (sysc_soc->nb.notifier_call)
+ cpu_pm_unregister_notifier(&sysc_soc->nb);
+
mutex_lock(&sysc_soc->list_lock);
+ list_for_each_safe(pos, tmp, &sysc_soc->restored_modules) {
+ restored_module = list_entry(pos, struct sysc_module, node);
+ list_del(pos);
+ kfree(restored_module);
+ }
list_for_each_safe(pos, tmp, &sysc_soc->disabled_modules) {
disabled_module = list_entry(pos, struct sysc_address, node);
list_del(pos);
@@ -3136,7 +3229,7 @@ static int sysc_probe(struct platform_device *pdev)
ddata->dev = &pdev->dev;
platform_set_drvdata(pdev, ddata);
- error = sysc_init_soc(ddata);
+ error = sysc_init_static_data(ddata);
if (error)
return error;
@@ -3234,6 +3327,9 @@ static int sysc_probe(struct platform_device *pdev)
pm_runtime_put(&pdev->dev);
}
+ if (ddata->cfg.quirks & SYSC_QUIRK_REINIT_ON_CTX_LOST)
+ sysc_add_restored(ddata);
+
return 0;
err:
@@ -3315,7 +3411,7 @@ static void __exit sysc_exit(void)
{
bus_unregister_notifier(&platform_bus_type, &sysc_nb);
platform_driver_unregister(&sysc_driver);
- sysc_cleanup_soc();
+ sysc_cleanup_static_data();
}
module_exit(sysc_exit);
diff --git a/include/linux/platform_data/ti-sysc.h b/include/linux/platform_data/ti-sysc.h
--- a/include/linux/platform_data/ti-sysc.h
+++ b/include/linux/platform_data/ti-sysc.h
@@ -50,6 +50,7 @@ struct sysc_regbits {
s8 emufree_shift;
};
+#define SYSC_QUIRK_REINIT_ON_CTX_LOST BIT(28)
#define SYSC_QUIRK_REINIT_ON_RESUME BIT(27)
#define SYSC_QUIRK_GPMC_DEBUG BIT(26)
#define SYSC_MODULE_QUIRK_ENA_RESETDONE BIT(25)
--
2.33.0
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