ufs: add UFS power management support

This patch adds support for UFS device and UniPro link power management
during runtime/system PM.

Main idea is to define multiple UFS low power levels based on UFS device
and UFS link power states. This would allow any specific platform or pci
driver to choose the best suited low power level during runtime and
system suspend based on their power goals.

bkops handlig:
To put the UFS device in sleep state when bkops is disabled, first query
the bkops status from the device and enable bkops on device only if
device needs time to perform the bkops.

START_STOP handling:
Before sending START_STOP_UNIT to the device well-known logical unit
(w-lun) to make sure that the device w-lun unit attention condition is
cleared.

Write protection:
UFS device specification allows LUs to be write protected, either
permanently or power on write protected. If any LU is power on write
protected and if the card is power cycled (by powering off VCCQ and/or
VCC rails), LU's write protect status would be lost. So this means those
LUs can be written now. To ensures that UFS device is power cycled only
if the power on protect is not set for any of the LUs, check if power on
write protect is set and if device is in sleep/power-off state & link in
inactive state (Hibern8 or OFF state).
If none of the Logical Units on UFS device is power on write protected
then all UFS device power rails (VCC, VCCQ & VCCQ2) can be turned off if
UFS device is in power-off state and UFS link is in OFF state. But current
implementation would disable all device power rails even if UFS link is
not in OFF state.

Low power mode:
If UFS link is in OFF state then UFS host controller can be power collapsed
to avoid leakage current from it. Note that if UFS host controller is power
collapsed, full UFS reinitialization will be required on resume to
re-establish the link between host and device.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 35 insertions, 1 deletions

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 37d64c1fb8da..42c459a9d3fe 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -129,6 +129,7 @@ enum {
 /* Flag idn for Query Requests*/
 enum flag_idn {
 	QUERY_FLAG_IDN_FDEVICEINIT      = 0x01,
+	QUERY_FLAG_IDN_PWR_ON_WPE	= 0x03,
 	QUERY_FLAG_IDN_BKOPS_EN         = 0x04,
 };
 
@@ -194,6 +195,18 @@ enum unit_desc_param {
 	UNIT_DESC_PARAM_LARGE_UNIT_SIZE_M1	= 0x22,
 };
 
+/*
+ * Logical Unit Write Protect
+ * 00h: LU not write protected
+ * 01h: LU write protected when fPowerOnWPEn =1
+ * 02h: LU permanently write protected when fPermanentWPEn =1
+ */
+enum ufs_lu_wp_type {
+	UFS_LU_NO_WP		= 0x00,
+	UFS_LU_POWER_ON_WP	= 0x01,
+	UFS_LU_PERM_WP		= 0x02,
+};
+
 /* bActiveICCLevel parameter current units */
 enum {
 	UFSHCD_NANO_AMP		= 0,
@@ -226,11 +239,12 @@ enum {
 };
 
 /* Background operation status */
-enum {
+enum bkops_status {
 	BKOPS_STATUS_NO_OP               = 0x0,
 	BKOPS_STATUS_NON_CRITICAL        = 0x1,
 	BKOPS_STATUS_PERF_IMPACT         = 0x2,
 	BKOPS_STATUS_CRITICAL            = 0x3,
+	BKOPS_STATUS_MAX		 = BKOPS_STATUS_CRITICAL,
 };
 
 /* UTP QUERY Transaction Specific Fields OpCode */
@@ -291,6 +305,14 @@ enum {
 	UPIU_TASK_MANAGEMENT_FUNC_FAILED	= 0x05,
 	UPIU_INCORRECT_LOGICAL_UNIT_NO		= 0x09,
 };
+
+/* UFS device power modes */
+enum ufs_dev_pwr_mode {
+	UFS_ACTIVE_PWR_MODE	= 1,
+	UFS_SLEEP_PWR_MODE	= 2,
+	UFS_POWERDOWN_PWR_MODE	= 3,
+};
+
 /**
  * struct utp_upiu_header - UPIU header structure
  * @dword_0: UPIU header DW-0
@@ -437,6 +459,12 @@ struct ufs_query_res {
 #define UFS_VREG_VCCQ2_MIN_UV	   1650000 /* uV */
 #define UFS_VREG_VCCQ2_MAX_UV	   1950000 /* uV */
 
+/*
+ * VCCQ & VCCQ2 current requirement when UFS device is in sleep state
+ * and link is in Hibern8 state.
+ */
+#define UFS_VREG_LPM_LOAD_UA	1000 /* uA */
+
 struct ufs_vreg {
 	struct regulator *reg;
 	const char *name;
@@ -454,4 +482,10 @@ struct ufs_vreg_info {
 	struct ufs_vreg *vdd_hba;
 };
 
+struct ufs_dev_info {
+	bool f_power_on_wp_en;
+	/* Keeps information if any of the LU is power on write protected */
+	bool is_lu_power_on_wp;
+};
+
 #endif /* End of Header */