This patch adds support for save and restore for clock registers
which loses register contents across power domain off/on sequence.
Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Cc: Mike Turquette <mturquette@xxxxxxxxxx>
Reviewed-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
---
drivers/clk/samsung/clk.c | 66 +++++++++++++++++++++++++++++++++++++++++++++
drivers/clk/samsung/clk.h | 14 ++++++++++
2 files changed, 80 insertions(+)
diff --git a/drivers/clk/samsung/clk.c b/drivers/clk/samsung/clk.c
index dd1f7c9..9fd1369 100644
--- a/drivers/clk/samsung/clk.c
+++ b/drivers/clk/samsung/clk.c
@@ -11,10 +11,12 @@
* clock framework for Samsung platforms.
*/
+#include <linux/pm_domain.h>
#include <linux/syscore_ops.h>
#include "clk.h"
static LIST_HEAD(clock_reg_cache_list);
+static LIST_HEAD(clock_pd_reg_cache_list);
void samsung_clk_save(void __iomem *base,
struct samsung_clk_reg_dump *rd,
@@ -370,6 +372,67 @@ static void samsung_clk_sleep_init(void __iomem *reg_base,
unsigned long nr_rdump) {}
#endif
+static int samsung_power_domain_notifier(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct generic_pm_domain *genpd = data;
+ struct samsung_clock_pd_reg_cache *reg_cache;
+
+ switch (event) {
+ case GPD_OFF_PRE:
+ /* save all the pd domain clock registers */
+ list_for_each_entry(reg_cache, &clock_pd_reg_cache_list, node)
+ if (!strcmp(reg_cache->pd_name, genpd->name))
+ samsung_clk_save(reg_cache->reg_base,
+ reg_cache->rdump,
+ reg_cache->rd_num);
+ break;
+ case GPD_ON_POST:
+ /* restore all the pd domain clock registers */
+ list_for_each_entry(reg_cache, &clock_pd_reg_cache_list, node)
+ if (!strcmp(reg_cache->pd_name, genpd->name))
+ samsung_clk_restore(reg_cache->reg_base,
+ reg_cache->rdump,
+ reg_cache->rd_num);
+ break;
+ case GPD_OFF_POST:
+ case GPD_ON_PRE:
+ break;
+ default:
+ pr_err("%s: Invalid pm domain event\n", __func__);
+ }
+ return 0;
+}
+
+/* Notifier for power domain on/off changes */
+static struct notifier_block power_domain_notifier_block = {
+ .notifier_call = samsung_power_domain_notifier,
+};
+
+static void samsung_clk_pd_init(void __iomem *reg_base,
+ const unsigned long *rdump, unsigned long nr_rdump,
+ char *pd_name)
+{
+ struct samsung_clock_pd_reg_cache *pd_reg_cache;
+
+ pd_reg_cache = kzalloc(sizeof(struct samsung_clock_pd_reg_cache),
+ GFP_KERNEL);
+ if (!pd_reg_cache)
+ panic("could not allocate register reg_cache.\n");
+
+ pd_reg_cache->rdump = samsung_clk_alloc_reg_dump(rdump, nr_rdump);
+
+ if (!pd_reg_cache->rdump)
+ panic("could not allocate register dump storage.\n");
+
+ pd_reg_cache->reg_base = reg_base;
+ pd_reg_cache->rd_num = nr_rdump;
+ pd_reg_cache->pd_name = pd_name;
+ list_add_tail(&pd_reg_cache->node, &clock_pd_reg_cache_list);
+
+ genpd_register_notifier(&power_domain_notifier_block, pd_name);
+}
+
/*
* Common function which registers plls, muxes, dividers and gates
* for each CMU. It also add CMU register list to register cache.
@@ -408,6 +471,9 @@ void __init samsung_cmu_register_one(struct device_node *np,
if (cmu->clk_regs)
samsung_clk_sleep_init(reg_base, cmu->clk_regs,
cmu->nr_clk_regs);
+ if (cmu->pd_clk_regs)
+ samsung_clk_pd_init(reg_base, cmu->pd_clk_regs,
+ cmu->nr_clk_regs, cmu->pd_name);
samsung_clk_of_add_provider(np, ctx);
}
diff --git a/drivers/clk/samsung/clk.h b/drivers/clk/samsung/clk.h
index 3f471e9..f67f5e5 100644
--- a/drivers/clk/samsung/clk.h
+++ b/drivers/clk/samsung/clk.h
@@ -331,6 +331,14 @@ struct samsung_clock_reg_cache {
unsigned int rd_num;
};
+struct samsung_clock_pd_reg_cache {
+ struct list_head node;
+ void __iomem *reg_base;
+ struct samsung_clk_reg_dump *rdump;
+ unsigned int rd_num;
+ char *pd_name;
+};
+
struct samsung_cmu_info {
/* list of pll clocks and respective count */
struct samsung_pll_clock *pll_clks;
@@ -356,6 +364,12 @@ struct samsung_cmu_info {
/* list and number of clocks registers */
unsigned long *clk_regs;
unsigned int nr_clk_regs;
+
+ /* list and number of clocks to be saved/restored during
+ * power domain shutdown */
+ char *pd_name;
+ unsigned long *pd_clk_regs;
+ unsigned int nr_pd_clk_regs;
};
extern struct samsung_clk_provider *__init samsung_clk_init(
--
1.7.9.5
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