[PATCH 5.15 018/279] bus: ti-sysc: Add quirk handling for reinit on context lost

Greg Kroah-Hartman
2021-11-24T13:47:31Z

From: Tony Lindgren <tony@atomide.com>

[ Upstream commit 9d881361206ebcf6285c2ec2ef275aff80875347 ]

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@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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
index f47c7e20cc271..7c645754a82b1 100644
--- 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 {
@@ -2442,6 +2450,79 @@ 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
@@ -2941,12 +3022,14 @@ 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;
@@ -2962,6 +3045,7 @@ 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);
@@ -3026,15 +3110,24 @@ 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);
@@ -3102,7 +3195,7 @@ 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;

@@ -3200,6 +3293,9 @@ 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:
@@ -3281,7 +3377,7 @@ 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
index 9837fb011f2fb..989aa30c598dc 100644
--- 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