UPSTREAM: clk: rockchip: only enter pll slow-mode directly before reboots on rk3288

As commit 1d33929e2a2b ("clk: rockchip: switch PLLs to slow mode before
reboot for rk3288") states, switching the PLLs to slow-mode is only
necessary when rebooting using the soft-reset done through the CRU.

The dwc2 controllers used create really big number of interrupts in
special constellations involving usb-hubs and their number is so high,
it can even overwhelm the interrupt handler if the cpu-speed os to low.

Right now the PLLs are put into slow-mode in a shutdown syscore_ops
callback which means it happens on all reboots (not only the soft-reset
ones) and even on poweroff actions.

This can result in the system not powering off and getting stuck instead,
so we should move the slow-mode change nearer to the actual reboot action.

For this we introduce the possiblity to also set a callback that gets
called from the restart-handler directly prior to restarting the system
and move the shutdown-callback to this new option.

With this the slow-mode switch is done only on the necessary reboots
and also has a smaller possibility of causing artifacts.

Fixes: 1d33929e2a2b ("clk: rockchip: switch PLLs to slow mode before reboot for rk3288")
Signed-off-by: Heiko Stuebner <heiko.stuebner@collabora.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
(cherry picked from commit dfff24bde7fb8d57482e907d5dfb0be3a9e28119)

Conflicts:

	drivers/clk/rockchip/clk-rk3228.c
[zx: there is no rk3228 clock controller, apply for clk-rk3366]

Change-Id: I2e91afd893c87eb3ab8a41db1fe81f5c43409951
Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>

7 files changed, 13 insertions, 8 deletions

diff --git a/drivers/clk/rockchip/clk-rk3036.c b/drivers/clk/rockchip/clk-rk3036.c
index 34c78f499ab7..c289fdc3a17f 100644
--- a/drivers/clk/rockchip/clk-rk3036.c
+++ b/drivers/clk/rockchip/clk-rk3036.c
@@ -488,6 +488,6 @@ static void __init rk3036_clk_init(struct device_node *np)
 	rockchip_register_softrst(np, 9, reg_base + RK2928_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-	rockchip_register_restart_notifier(RK2928_GLB_SRST_FST);
+	rockchip_register_restart_notifier(RK2928_GLB_SRST_FST, NULL);
 }
 CLK_OF_DECLARE(rk3036_cru, "rockchip,rk3036-cru", rk3036_clk_init);
diff --git a/drivers/clk/rockchip/clk-rk3188.c b/drivers/clk/rockchip/clk-rk3188.c
index 1211af71849d..7f7444cbf6fc 100644
--- a/drivers/clk/rockchip/clk-rk3188.c
+++ b/drivers/clk/rockchip/clk-rk3188.c
@@ -780,7 +780,7 @@ static void __init rk3188_common_clk_init(struct device_node *np)
 	rockchip_register_softrst(np, 9, reg_base + RK2928_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-	rockchip_register_restart_notifier(RK2928_GLB_SRST_FST);
+	rockchip_register_restart_notifier(RK2928_GLB_SRST_FST, NULL);
 }
 
 static void __init rk3066a_clk_init(struct device_node *np)
diff --git a/drivers/clk/rockchip/clk-rk3288.c b/drivers/clk/rockchip/clk-rk3288.c
index 2b4adfe5140d..05589e56d7da 100644
--- a/drivers/clk/rockchip/clk-rk3288.c
+++ b/drivers/clk/rockchip/clk-rk3288.c
@@ -874,7 +874,6 @@ static void rk3288_clk_shutdown(void)
 static struct syscore_ops rk3288_clk_syscore_ops = {
 	.suspend = rk3288_clk_suspend,
 	.resume = rk3288_clk_resume,
-	.shutdown = rk3288_clk_shutdown,
 };
 
 static void __init rk3288_clk_init(struct device_node *np)
@@ -932,7 +931,8 @@ static void __init rk3288_clk_init(struct device_node *np)
 				  rk3288_cru_base + RK3288_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-	rockchip_register_restart_notifier(RK3288_GLB_SRST_FST);
+	rockchip_register_restart_notifier(RK3288_GLB_SRST_FST,
+					   rk3288_clk_shutdown);
 	register_syscore_ops(&rk3288_clk_syscore_ops);
 }
 CLK_OF_DECLARE(rk3288_cru, "rockchip,rk3288-cru", rk3288_clk_init);
diff --git a/drivers/clk/rockchip/clk-rk3366.c b/drivers/clk/rockchip/clk-rk3366.c
index 4c892a6224e6..8c95e0744085 100644
--- a/drivers/clk/rockchip/clk-rk3366.c
+++ b/drivers/clk/rockchip/clk-rk3366.c
@@ -854,6 +854,6 @@ static void __init rk3366_clk_init(struct device_node *np)
 	rockchip_register_softrst(np, 15, reg_base + RK3368_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-	rockchip_register_restart_notifier(RK3368_GLB_SRST_FST);
+	rockchip_register_restart_notifier(RK3368_GLB_SRST_FST, NULL);
 }
 CLK_OF_DECLARE(rk3368_cru, "rockchip,rk3366-cru", rk3366_clk_init);
diff --git a/drivers/clk/rockchip/clk-rk3368.c b/drivers/clk/rockchip/clk-rk3368.c
index cdaba8587437..74c4ea65d3fe 100644
--- a/drivers/clk/rockchip/clk-rk3368.c
+++ b/drivers/clk/rockchip/clk-rk3368.c
@@ -908,6 +908,6 @@ static void __init rk3368_clk_init(struct device_node *np)
 	rockchip_register_softrst(np, 15, reg_base + RK3368_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-	rockchip_register_restart_notifier(RK3368_GLB_SRST_FST);
+	rockchip_register_restart_notifier(RK3368_GLB_SRST_FST, NULL);
 }
 CLK_OF_DECLARE(rk3368_cru, "rockchip,rk3368-cru", rk3368_clk_init);
diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
index 3c73703fb180..1ac942d546a2 100644
--- a/drivers/clk/rockchip/clk.c
+++ b/drivers/clk/rockchip/clk.c
@@ -507,9 +507,13 @@ void __init rockchip_clk_protect_critical(const char *const clocks[],
 }
 
 static unsigned int reg_restart;
+static void (*cb_restart)(void);
 static int rockchip_restart_notify(struct notifier_block *this,
 				   unsigned long mode, void *cmd)
 {
+	if (cb_restart)
+		cb_restart();
+
 	writel(0xfdb9, reg_base + reg_restart);
 	return NOTIFY_DONE;
 }
@@ -519,11 +523,12 @@ static struct notifier_block rockchip_restart_handler = {
 	.priority = 128,
 };
 
-void __init rockchip_register_restart_notifier(unsigned int reg)
+void __init rockchip_register_restart_notifier(unsigned int reg, void (*cb)(void))
 {
 	int ret;
 
 	reg_restart = reg;
+	cb_restart = cb;
 	ret = register_restart_handler(&rockchip_restart_handler);
 	if (ret)
 		pr_err("%s: cannot register restart handler, %d\n",
diff --git a/drivers/clk/rockchip/clk.h b/drivers/clk/rockchip/clk.h
index f0f07ce14723..7e3a084f92c0 100644
--- a/drivers/clk/rockchip/clk.h
+++ b/drivers/clk/rockchip/clk.h
@@ -558,7 +558,7 @@ void rockchip_clk_register_armclk(unsigned int lookup_id, const char *name,
 			const struct rockchip_cpuclk_rate_table *rates,
 			int nrates);
 void rockchip_clk_protect_critical(const char *const clocks[], int nclocks);
-void rockchip_register_restart_notifier(unsigned int reg);
+void rockchip_register_restart_notifier(unsigned int reg, void (*cb)(void));
 
 #define ROCKCHIP_SOFTRST_HIWORD_MASK	BIT(0)