scsi: ufs: add load based scaling of UFS gear

UFS driver's load based clock scaling feature scales down the ufs related
clocks in order to allow low power modes of chipsets. UniPro 1.6 supports
maximum gear up to HS-G3 (High Speed Gear3) and some of the chipsets
low power modes may not be allowed in HS-G3 hence this change adds support
to scale gear between HS-G3 and HS-G1 based on same existing load based
clock scaling logic.
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.h

@@ -45,6 +45,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/rwsem.h>
 #include <linux/workqueue.h>
 #include <linux/errno.h>
 #include <linux/types.h>
@@ -351,6 +352,11 @@ struct ufs_clk_gating {
 	int active_reqs;
 };
 
+struct ufs_saved_pwr_info {
+	struct ufs_pa_layer_attr info;
+	bool is_valid;
+};
+
 struct ufs_clk_scaling {
 	ktime_t  busy_start_t;
 	bool is_busy_started;
@@ -358,6 +364,7 @@ struct ufs_clk_scaling {
 	unsigned long window_start_t;
 	struct device_attribute enable_attr;
 	bool is_allowed;
+	struct ufs_saved_pwr_info saved_pwr_info;
 };
 
 /**
@@ -634,6 +641,8 @@ struct ufs_hba {
 
 	enum bkops_status urgent_bkops_lvl;
 	bool is_urgent_bkops_lvl_checked;
+
+	struct rw_semaphore clk_scaling_lock;
 };
 
 /* Returns true if clocks can be gated. Otherwise false */