Re: [PATCH 6/6] HSI: omap-ssi: add clk change support

[Pavel Machek]

On Sat 2016-04-30 04:09:13, Sebastian Reichel wrote:
> This adds support for frequency changes of the SSI
> functional clock, which may occur due to DVFS.
> 
> Signed-off-By: Sebastian Reichel 

Acked-by: Pavel Machek 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [PATCH 6/6] HSI: omap-ssi: add clk change support

[Pavel Machek]

On Sat 2016-04-30 04:09:13, Sebastian Reichel wrote:
> This adds support for frequency changes of the SSI
> functional clock, which may occur due to DVFS.
> 
> Signed-off-By: Sebastian Reichel 

Acked-by: Pavel Machek 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[PATCH 6/6] HSI: omap-ssi: add clk change support

[Sebastian Reichel]

This adds support for frequency changes of the SSI
functional clock, which may occur due to DVFS.

Signed-off-By: Sebastian Reichel 
---
 drivers/hsi/controllers/omap_ssi.h  |  6 
 drivers/hsi/controllers/omap_ssi_core.c | 63 +
 drivers/hsi/controllers/omap_ssi_port.c | 20 +++
 3 files changed, 89 insertions(+)

diff --git a/drivers/hsi/controllers/omap_ssi.h 
b/drivers/hsi/controllers/omap_ssi.h
index e493321cb0c3..7b4dec2c69ff 100644
--- a/drivers/hsi/controllers/omap_ssi.h
+++ b/drivers/hsi/controllers/omap_ssi.h
@@ -134,6 +134,8 @@ struct gdd_trn {
  * @gdd_tasklet: bottom half for DMA transfers
  * @gdd_trn: Array of GDD transaction data for ongoing GDD transfers
  * @lock: lock to serialize access to GDD
+ * @fck_nb: DVFS notfifier block
+ * @fck_rate: clock rate
  * @loss_count: To follow if we need to restore context or not
  * @max_speed: Maximum TX speed (Kb/s) set by the clients.
  * @sysconfig: SSI controller saved context
@@ -151,6 +153,7 @@ struct omap_ssi_controller {
struct tasklet_struct   gdd_tasklet;
struct gdd_trn  gdd_trn[SSI_MAX_GDD_LCH];
spinlock_t  lock;
+   struct notifier_block   fck_nb;
unsigned long   fck_rate;
u32 loss_count;
u32 max_speed;
@@ -164,6 +167,9 @@ struct omap_ssi_controller {
 #endif
 };
 
+void omap_ssi_port_update_fclk(struct hsi_controller *ssi,
+  struct omap_ssi_port *omap_port);
+
 extern struct platform_driver ssi_port_pdriver;
 
 #endif /* __LINUX_HSI_OMAP_SSI_H__ */
diff --git a/drivers/hsi/controllers/omap_ssi_core.c 
b/drivers/hsi/controllers/omap_ssi_core.c
index 535c76038288..15b2a600d77b 100644
--- a/drivers/hsi/controllers/omap_ssi_core.c
+++ b/drivers/hsi/controllers/omap_ssi_core.c
@@ -290,6 +290,64 @@ static unsigned long ssi_get_clk_rate(struct 
hsi_controller *ssi)
return rate;
 }
 
+static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
+   void *data)
+{
+   struct omap_ssi_controller *omap_ssi = container_of(nb,
+   struct omap_ssi_controller, fck_nb);
+   struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
+   struct clk_notifier_data *clk_data = data;
+   struct omap_ssi_port *omap_port;
+   int i;
+
+   switch (event) {
+   case PRE_RATE_CHANGE:
+   dev_dbg(>device, "pre rate change\n");
+
+   for (i = 0; i < ssi->num_ports; i++) {
+   omap_port = omap_ssi->port[i];
+
+   if (!omap_port)
+   continue;
+
+   /* Workaround for SWBREAK + CAwake down race in CMT */
+   tasklet_disable(_port->wake_tasklet);
+
+   /* stop all ssi communication */
+   pinctrl_pm_select_idle_state(omap_port->pdev);
+   udelay(1); /* wait for racing frames */
+   }
+
+   break;
+   case ABORT_RATE_CHANGE:
+   dev_dbg(>device, "abort rate change\n");
+   /* Fall through */
+   case POST_RATE_CHANGE:
+   dev_dbg(>device, "post rate change (%lu -> %lu)\n",
+   clk_data->old_rate, clk_data->new_rate);
+   omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 
1000); /* KHz */
+
+   for (i = 0; i < ssi->num_ports; i++) {
+   omap_port = omap_ssi->port[i];
+
+   if (!omap_port)
+   continue;
+
+   omap_ssi_port_update_fclk(ssi, omap_port);
+
+   /* resume ssi communication */
+   pinctrl_pm_select_default_state(omap_port->pdev);
+   tasklet_enable(_port->wake_tasklet);
+   }
+
+   break;
+   default:
+   break;
+   }
+
+   return NOTIFY_DONE;
+}
+
 static int ssi_get_iomem(struct platform_device *pd,
const char *name, void __iomem **pbase, dma_addr_t *phy)
 {
@@ -369,6 +427,10 @@ static int ssi_add_controller(struct hsi_controller *ssi,
goto out_err;
}
 
+   omap_ssi->fck_nb.notifier_call = ssi_clk_event;
+   omap_ssi->fck_nb.priority = INT_MAX;
+   clk_notifier_register(omap_ssi->fck, _ssi->fck_nb);
+
/* TODO: find register, which can be used to detect context loss */
omap_ssi->get_loss = NULL;
 
@@ -432,6 +494,7 @@ static void ssi_remove_controller(struct hsi_controller 
*ssi)
int id = ssi->id;
tasklet_kill(_ssi->gdd_tasklet);
hsi_unregister_controller(ssi);
+   clk_notifier_unregister(omap_ssi->fck, _ssi->fck_nb);
ida_simple_remove(_omap_ssi_ida, id);
 }
 
diff --git 

[PATCH 6/6] HSI: omap-ssi: add clk change support

[Sebastian Reichel]

This adds support for frequency changes of the SSI
functional clock, which may occur due to DVFS.

Signed-off-By: Sebastian Reichel 
---
 drivers/hsi/controllers/omap_ssi.h  |  6 
 drivers/hsi/controllers/omap_ssi_core.c | 63 +
 drivers/hsi/controllers/omap_ssi_port.c | 20 +++
 3 files changed, 89 insertions(+)

diff --git a/drivers/hsi/controllers/omap_ssi.h 
b/drivers/hsi/controllers/omap_ssi.h
index e493321cb0c3..7b4dec2c69ff 100644
--- a/drivers/hsi/controllers/omap_ssi.h
+++ b/drivers/hsi/controllers/omap_ssi.h
@@ -134,6 +134,8 @@ struct gdd_trn {
  * @gdd_tasklet: bottom half for DMA transfers
  * @gdd_trn: Array of GDD transaction data for ongoing GDD transfers
  * @lock: lock to serialize access to GDD
+ * @fck_nb: DVFS notfifier block
+ * @fck_rate: clock rate
  * @loss_count: To follow if we need to restore context or not
  * @max_speed: Maximum TX speed (Kb/s) set by the clients.
  * @sysconfig: SSI controller saved context
@@ -151,6 +153,7 @@ struct omap_ssi_controller {
struct tasklet_struct   gdd_tasklet;
struct gdd_trn  gdd_trn[SSI_MAX_GDD_LCH];
spinlock_t  lock;
+   struct notifier_block   fck_nb;
unsigned long   fck_rate;
u32 loss_count;
u32 max_speed;
@@ -164,6 +167,9 @@ struct omap_ssi_controller {
 #endif
 };
 
+void omap_ssi_port_update_fclk(struct hsi_controller *ssi,
+  struct omap_ssi_port *omap_port);
+
 extern struct platform_driver ssi_port_pdriver;
 
 #endif /* __LINUX_HSI_OMAP_SSI_H__ */
diff --git a/drivers/hsi/controllers/omap_ssi_core.c 
b/drivers/hsi/controllers/omap_ssi_core.c
index 535c76038288..15b2a600d77b 100644
--- a/drivers/hsi/controllers/omap_ssi_core.c
+++ b/drivers/hsi/controllers/omap_ssi_core.c
@@ -290,6 +290,64 @@ static unsigned long ssi_get_clk_rate(struct 
hsi_controller *ssi)
return rate;
 }
 
+static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
+   void *data)
+{
+   struct omap_ssi_controller *omap_ssi = container_of(nb,
+   struct omap_ssi_controller, fck_nb);
+   struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
+   struct clk_notifier_data *clk_data = data;
+   struct omap_ssi_port *omap_port;
+   int i;
+
+   switch (event) {
+   case PRE_RATE_CHANGE:
+   dev_dbg(>device, "pre rate change\n");
+
+   for (i = 0; i < ssi->num_ports; i++) {
+   omap_port = omap_ssi->port[i];
+
+   if (!omap_port)
+   continue;
+
+   /* Workaround for SWBREAK + CAwake down race in CMT */
+   tasklet_disable(_port->wake_tasklet);
+
+   /* stop all ssi communication */
+   pinctrl_pm_select_idle_state(omap_port->pdev);
+   udelay(1); /* wait for racing frames */
+   }
+
+   break;
+   case ABORT_RATE_CHANGE:
+   dev_dbg(>device, "abort rate change\n");
+   /* Fall through */
+   case POST_RATE_CHANGE:
+   dev_dbg(>device, "post rate change (%lu -> %lu)\n",
+   clk_data->old_rate, clk_data->new_rate);
+   omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 
1000); /* KHz */
+
+   for (i = 0; i < ssi->num_ports; i++) {
+   omap_port = omap_ssi->port[i];
+
+   if (!omap_port)
+   continue;
+
+   omap_ssi_port_update_fclk(ssi, omap_port);
+
+   /* resume ssi communication */
+   pinctrl_pm_select_default_state(omap_port->pdev);
+   tasklet_enable(_port->wake_tasklet);
+   }
+
+   break;
+   default:
+   break;
+   }
+
+   return NOTIFY_DONE;
+}
+
 static int ssi_get_iomem(struct platform_device *pd,
const char *name, void __iomem **pbase, dma_addr_t *phy)
 {
@@ -369,6 +427,10 @@ static int ssi_add_controller(struct hsi_controller *ssi,
goto out_err;
}
 
+   omap_ssi->fck_nb.notifier_call = ssi_clk_event;
+   omap_ssi->fck_nb.priority = INT_MAX;
+   clk_notifier_register(omap_ssi->fck, _ssi->fck_nb);
+
/* TODO: find register, which can be used to detect context loss */
omap_ssi->get_loss = NULL;
 
@@ -432,6 +494,7 @@ static void ssi_remove_controller(struct hsi_controller 
*ssi)
int id = ssi->id;
tasklet_kill(_ssi->gdd_tasklet);
hsi_unregister_controller(ssi);
+   clk_notifier_unregister(omap_ssi->fck, _ssi->fck_nb);
ida_simple_remove(_omap_ssi_ida, id);
 }
 
diff --git a/drivers/hsi/controllers/omap_ssi_port.c