video: tegra: host: Add ioctl to set/get clk rate

Host modules are initialized to max rate. Not all use cases
require clocks at max rate, which increases the power consumption.
Modules from user space can request for the lower clk rate
using this ioctl.

Bug 850467

Original-Change-Id: I1c7a8dfd159460e7c5a27813e3a08a992a20c132
Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Reviewed-on: http://git-master/r/44579
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Tested-by: Bharat Nihalani <bnihalani@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

Rebase-Id: R0cffab971c5ac6adde28af4777354a1ecae4c54d

1 files changed, 105 insertions, 0 deletions

diff --git a/drivers/video/tegra/host/nvhost_acm.c b/drivers/video/tegra/host/nvhost_acm.c
index 4d14dc1093dd..e477d5a6ad85 100644
--- a/drivers/video/tegra/host/nvhost_acm.c
+++ b/drivers/video/tegra/host/nvhost_acm.c
@@ -21,6 +21,7 @@
  */
 
 #include "dev.h"
+#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/sched.h>
 #include <linux/err.h>
@@ -128,6 +129,109 @@ static bool _3d_powergating_disabled(void)
 	return 1;
 }
 
+#if !defined(CONFIG_ARCH_TEGRA_2x_SOC)
+int nvhost_module_get_rate(struct nvhost_module *mod, unsigned long *rate,
+			    int index)
+{
+	struct clk *c;
+
+	c = mod->clk[index];
+	if (IS_ERR_OR_NULL(c))
+		return -EINVAL;
+
+	*rate = clk_get_rate(c);
+	return 0;
+}
+
+int nvhost_module_update_rate(struct nvhost_module *mod, int index)
+{
+	unsigned long rate = 0;
+	struct nvhost_module_client *m;
+
+	list_for_each_entry(m, &mod->client_list, node) {
+		rate = max(m->rate[index], rate);
+	}
+	if (!mod->clk[index])
+		return -EINVAL;
+	clk_set_rate(mod->clk[index], rate);
+	return 0;
+}
+
+int nvhost_module_set_rate(struct nvhost_module *mod, void *priv,
+			    unsigned long rate, int index)
+{
+	struct nvhost_module_client *m;
+
+	list_for_each_entry(m, &mod->client_list, node) {
+		if (m->priv == priv) {
+			rate = clk_round_rate(mod->clk[index], rate);
+			m->rate[index] = rate;
+			break;
+		}
+	}
+	return nvhost_module_update_rate(mod, index);
+}
+
+int nvhost_module_add_client(struct nvhost_module *mod, void *priv)
+{
+	int i;
+	unsigned long rate;
+	struct nvhost_module_client *client;
+
+	client = kzalloc(sizeof(*client), GFP_KERNEL);
+	if (!client) {
+		return -ENOMEM;
+	}
+	INIT_LIST_HEAD(&client->node);
+	client->priv = priv;
+
+	for (i = 0; i < mod->num_clks; i++) {
+		rate = clk_round_rate(mod->clk[i], 0);
+		client->rate[i] = rate;
+	}
+	list_add_tail(&client->node, &mod->client_list);
+	return 0;
+}
+
+void nvhost_module_remove_client(struct nvhost_module *mod, void *priv)
+{
+	int i;
+	struct nvhost_module_client *m;
+
+	list_for_each_entry(m, &mod->client_list, node) {
+		if (priv == m->priv) {
+			list_del(&m->node);
+			break;
+		}
+	}
+	m->priv = NULL;
+	kfree(m);
+	for (i = 0; i < mod->num_clks; i++)
+		nvhost_module_update_rate(mod, i);
+}
+#else
+int nvhost_module_get_rate(struct nvhost_module *mod, unsigned long *rate,
+                            int index)
+{
+        return 0;
+}
+
+int nvhost_module_set_rate(struct nvhost_module *mod, void *priv,
+                            unsigned long rate, int index)
+{
+        return 0;
+}
+
+int nvhost_module_add_client(struct nvhost_module *mod, void *priv)
+{
+        return 0;
+}
+
+void nvhost_module_remove_client(struct nvhost_module *mod, void *priv)
+{
+}
+#endif
+
 int nvhost_module_init(struct nvhost_module *mod, const char *name,
 		nvhost_modulef func, struct nvhost_module *parent,
 		struct device *dev)
@@ -136,6 +240,7 @@ int nvhost_module_init(struct nvhost_module *mod, const char *name,
 
 	mod->name = name;
 
+	INIT_LIST_HEAD(&mod->client_list);
 	while (i < NVHOST_MODULE_MAX_CLOCKS) {
 		long rate;
 		mod->clk[i] = clk_get(dev, get_module_clk_id(name, i));