Commit 3d17b9b5 authored by Asutosh Das's avatar Asutosh Das Committed by Martin K. Petersen
Browse files

scsi: ufs: Add write booster feature support 

The write performance of TLC NAND is considerably lower than SLC NAND.
Using SLC NAND as a WriteBooster Buffer enables the write request to be
processed with lower latency and improves the overall write performance.

Adds support for shared-buffer mode WriteBooster.

WriteBooster enable: SW enables it when clocks are scaled up, thus it's
enabled only in high load conditions.

WriteBooster disable: SW will disable the feature, when clocks are scaled
down. Thus writes would go as normal writes.

To keep the endurance of the WriteBooster Buffer at a maximum, this
load-based toggling is adopted.

Link: https://lore.kernel.org/r/2871444d9083b0e9323ef6d8ff1b544b7784adc9.1587591527.git.asutoshd@codeaurora.org


Reviewed-by: default avatarAvri Altman <avri.altman@wdc.com>
Signed-off-by: default avatarAsutosh Das <asutoshd@codeaurora.org>
Signed-off-by: default avatarSubhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 7dfdcc39

drivers/scsi/ufs/ufs.h

+29 −2
Original line number Diff line number Diff line
@@ -140,6 +140,9 @@ enum flag_idn { 
	QUERY_FLAG_IDN_BUSY_RTC				= 0x09,

	QUERY_FLAG_IDN_RESERVED3			= 0x0A,

	QUERY_FLAG_IDN_PERMANENTLY_DISABLE_FW_UPDATE	= 0x0B,

	QUERY_FLAG_IDN_WB_EN                            = 0x0E,

	QUERY_FLAG_IDN_WB_BUFF_FLUSH_EN                 = 0x0F,

	QUERY_FLAG_IDN_WB_BUFF_FLUSH_DURING_HIBERN8     = 0x10,

};



/* Attribute idn for Query requests */
@@ -168,6 +171,10 @@ enum attr_idn { 
	QUERY_ATTR_IDN_PSA_STATE		= 0x15,

	QUERY_ATTR_IDN_PSA_DATA_SIZE		= 0x16,

	QUERY_ATTR_IDN_REF_CLK_GATING_WAIT_TIME	= 0x17,

	QUERY_ATTR_IDN_WB_FLUSH_STATUS	        = 0x1C,

	QUERY_ATTR_IDN_AVAIL_WB_BUFF_SIZE       = 0x1D,

	QUERY_ATTR_IDN_WB_BUFF_LIFE_TIME_EST    = 0x1E,

	QUERY_ATTR_IDN_CURR_WB_BUFF_SIZE        = 0x1F,

};



/* Descriptor idn for Query requests */
@@ -191,9 +198,9 @@ enum desc_header_offset { 
};



enum ufs_desc_def_size {

	QUERY_DESC_DEVICE_DEF_SIZE		= 0x40,

	QUERY_DESC_DEVICE_DEF_SIZE		= 0x59,

	QUERY_DESC_CONFIGURATION_DEF_SIZE	= 0x90,

	QUERY_DESC_UNIT_DEF_SIZE		= 0x23,

	QUERY_DESC_UNIT_DEF_SIZE		= 0x2D,

	QUERY_DESC_INTERCONNECT_DEF_SIZE	= 0x06,

	QUERY_DESC_GEOMETRY_DEF_SIZE		= 0x48,

	QUERY_DESC_POWER_DEF_SIZE		= 0x62,
@@ -219,6 +226,7 @@ enum unit_desc_param { 
	UNIT_DESC_PARAM_PHY_MEM_RSRC_CNT	= 0x18,

	UNIT_DESC_PARAM_CTX_CAPABILITIES	= 0x20,

	UNIT_DESC_PARAM_LARGE_UNIT_SIZE_M1	= 0x22,

	UNIT_DESC_PARAM_WB_BUF_ALLOC_UNITS	= 0x29,

};



/* Device descriptor parameters offsets in bytes*/
@@ -258,6 +266,10 @@ enum device_desc_param { 
	DEVICE_DESC_PARAM_PSA_MAX_DATA		= 0x25,

	DEVICE_DESC_PARAM_PSA_TMT		= 0x29,

	DEVICE_DESC_PARAM_PRDCT_REV		= 0x2A,

	DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP	= 0x4F,

	DEVICE_DESC_PARAM_WB_PRESRV_USRSPC_EN	= 0x53,

	DEVICE_DESC_PARAM_WB_TYPE		= 0x54,

	DEVICE_DESC_PARAM_WB_SHARED_ALLOC_UNITS = 0x55,

};



/* Interconnect descriptor parameters offsets in bytes*/
@@ -333,6 +345,11 @@ enum { 
	UFSHCD_AMP		= 3,

};



/* Possible values for dExtendedUFSFeaturesSupport */

enum {

	UFS_DEV_WRITE_BOOSTER_SUP	= BIT(8),

};



#define POWER_DESC_MAX_SIZE			0x62

#define POWER_DESC_MAX_ACTV_ICC_LVLS		16
@@ -447,6 +464,11 @@ enum ufs_dev_pwr_mode { 
	UFS_POWERDOWN_PWR_MODE	= 3,

};



enum ufs_dev_wb_buf_avail_size {

	UFS_WB_10_PERCENT_BUF_REMAIN = 0x1,

	UFS_WB_40_PERCENT_BUF_REMAIN = 0x4,

};



/**

 * struct utp_cmd_rsp - Response UPIU structure

 * @residual_transfer_count: Residual transfer count DW-3
@@ -537,6 +559,11 @@ struct ufs_dev_info { 
	u8 *model;

	u16 wspecversion;

	u32 clk_gating_wait_us;

	u32 d_ext_ufs_feature_sup;

	u8 b_wb_buffer_type;

	u32 d_wb_alloc_units;

	bool keep_vcc_on;

	u8 b_presrv_uspc_en;

};



/**

drivers/scsi/ufs/ufshcd.c

+248 −4
Original line number Diff line number Diff line
@@ -48,6 +48,8 @@ 
#include "unipro.h"

#include "ufs-sysfs.h"

#include "ufs_bsg.h"

#include <asm/unaligned.h>

#include <linux/blkdev.h>



#define CREATE_TRACE_POINTS

#include <trace/events/ufs.h>
@@ -251,6 +253,13 @@ static int ufshcd_scale_clks(struct ufs_hba *hba, bool scale_up); 
static irqreturn_t ufshcd_intr(int irq, void *__hba);

static int ufshcd_change_power_mode(struct ufs_hba *hba,

			     struct ufs_pa_layer_attr *pwr_mode);

static bool ufshcd_wb_sup(struct ufs_hba *hba);

static int ufshcd_wb_buf_flush_enable(struct ufs_hba *hba);

static int ufshcd_wb_buf_flush_disable(struct ufs_hba *hba);

static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable);

static int ufshcd_wb_toggle_flush_during_h8(struct ufs_hba *hba, bool set);

static inline void ufshcd_wb_toggle_flush(struct ufs_hba *hba, bool enable);



static inline bool ufshcd_valid_tag(struct ufs_hba *hba, int tag)

{

	return tag >= 0 && tag < hba->nutrs;
@@ -272,6 +281,25 @@ static inline void ufshcd_disable_irq(struct ufs_hba *hba) 
	}

}



static inline void ufshcd_wb_config(struct ufs_hba *hba)

{

	int ret;



	if (!ufshcd_wb_sup(hba))

		return;



	ret = ufshcd_wb_ctrl(hba, true);

	if (ret)

		dev_err(hba->dev, "%s: Enable WB failed: %d\n", __func__, ret);

	else

		dev_info(hba->dev, "%s: Write Booster Configured\n", __func__);

	ret = ufshcd_wb_toggle_flush_during_h8(hba, true);

	if (ret)

		dev_err(hba->dev, "%s: En WB flush during H8: failed: %d\n",

			__func__, ret);

	ufshcd_wb_toggle_flush(hba, true);

}



static void ufshcd_scsi_unblock_requests(struct ufs_hba *hba)

{

	if (atomic_dec_and_test(&hba->scsi_block_reqs_cnt))
@@ -1150,9 +1178,16 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up) 
	/* scale up the gear after scaling up clocks */

	if (scale_up) {

		ret = ufshcd_scale_gear(hba, true);

		if (ret)

		if (ret) {

			ufshcd_scale_clks(hba, false);

			goto out_unprepare;

		}

	}



	/* Enable Write Booster if we have scaled up else disable it */

	up_write(&hba->clk_scaling_lock);

	ufshcd_wb_ctrl(hba, scale_up);

	down_write(&hba->clk_scaling_lock);



out_unprepare:

	ufshcd_clock_scaling_unprepare(hba);
@@ -5161,6 +5196,166 @@ static void ufshcd_bkops_exception_event_handler(struct ufs_hba *hba) 
				__func__, err);

}



static bool ufshcd_wb_sup(struct ufs_hba *hba)

{

	return ufshcd_is_wb_allowed(hba);

}



static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable)

{

	int ret;

	enum query_opcode opcode;



	if (!ufshcd_wb_sup(hba))

		return 0;



	if (!(enable ^ hba->wb_enabled))

		return 0;

	if (enable)

		opcode = UPIU_QUERY_OPCODE_SET_FLAG;

	else

		opcode = UPIU_QUERY_OPCODE_CLEAR_FLAG;



	ret = ufshcd_query_flag_retry(hba, opcode,

				      QUERY_FLAG_IDN_WB_EN, NULL);

	if (ret) {

		dev_err(hba->dev, "%s write booster %s failed %d\n",

			__func__, enable ? "enable" : "disable", ret);

		return ret;

	}



	hba->wb_enabled = enable;

	dev_dbg(hba->dev, "%s write booster %s %d\n",

			__func__, enable ? "enable" : "disable", ret);



	return ret;

}



static int ufshcd_wb_toggle_flush_during_h8(struct ufs_hba *hba, bool set)

{

	int val;



	if (set)

		val =  UPIU_QUERY_OPCODE_SET_FLAG;

	else

		val = UPIU_QUERY_OPCODE_CLEAR_FLAG;



	return ufshcd_query_flag_retry(hba, val,

			       QUERY_FLAG_IDN_WB_BUFF_FLUSH_DURING_HIBERN8,

				       NULL);

}



static inline void ufshcd_wb_toggle_flush(struct ufs_hba *hba, bool enable)

{

	if (enable)

		ufshcd_wb_buf_flush_enable(hba);

	else

		ufshcd_wb_buf_flush_disable(hba);



}



static int ufshcd_wb_buf_flush_enable(struct ufs_hba *hba)

{

	int ret;



	if (!ufshcd_wb_sup(hba) || hba->wb_buf_flush_enabled)

		return 0;



	ret = ufshcd_query_flag_retry(hba, UPIU_QUERY_OPCODE_SET_FLAG,

				      QUERY_FLAG_IDN_WB_BUFF_FLUSH_EN, NULL);

	if (ret)

		dev_err(hba->dev, "%s WB - buf flush enable failed %d\n",

			__func__, ret);

	else

		hba->wb_buf_flush_enabled = true;



	dev_dbg(hba->dev, "WB - Flush enabled: %d\n", ret);

	return ret;

}



static int ufshcd_wb_buf_flush_disable(struct ufs_hba *hba)

{

	int ret;



	if (!ufshcd_wb_sup(hba) || !hba->wb_buf_flush_enabled)

		return 0;



	ret = ufshcd_query_flag_retry(hba, UPIU_QUERY_OPCODE_CLEAR_FLAG,

				      QUERY_FLAG_IDN_WB_BUFF_FLUSH_EN, NULL);

	if (ret) {

		dev_warn(hba->dev, "%s: WB - buf flush disable failed %d\n",

			 __func__, ret);

	} else {

		hba->wb_buf_flush_enabled = false;

		dev_dbg(hba->dev, "WB - Flush disabled: %d\n", ret);

	}



	return ret;

}



static bool ufshcd_wb_presrv_usrspc_keep_vcc_on(struct ufs_hba *hba,

						u32 avail_buf)

{

	u32 cur_buf;

	int ret;



	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,

					      QUERY_ATTR_IDN_CURR_WB_BUFF_SIZE,

					      0, 0, &cur_buf);

	if (ret) {

		dev_err(hba->dev, "%s dCurWriteBoosterBufferSize read failed %d\n",

			__func__, ret);

		return false;

	}



	if (!cur_buf) {

		dev_info(hba->dev, "dCurWBBuf: %d WB disabled until free-space is available\n",

			 cur_buf);

		return false;

	}

	/* Let it continue to flush when >60% full */

	if (avail_buf < UFS_WB_40_PERCENT_BUF_REMAIN)

		return true;



	return false;

}



static bool ufshcd_wb_keep_vcc_on(struct ufs_hba *hba)

{

	int ret;

	u32 avail_buf;



	if (!ufshcd_wb_sup(hba))

		return false;

	/*

	 * The ufs device needs the vcc to be ON to flush.

	 * With user-space reduction enabled, it's enough to enable flush

	 * by checking only the available buffer. The threshold

	 * defined here is > 90% full.

	 * With user-space preserved enabled, the current-buffer

	 * should be checked too because the wb buffer size can reduce

	 * when disk tends to be full. This info is provided by current

	 * buffer (dCurrentWriteBoosterBufferSize). There's no point in

	 * keeping vcc on when current buffer is empty.

	 */

	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,

				      QUERY_ATTR_IDN_AVAIL_WB_BUFF_SIZE,

				      0, 0, &avail_buf);

	if (ret) {

		dev_warn(hba->dev, "%s dAvailableWriteBoosterBufferSize read failed %d\n",

			 __func__, ret);

		return false;

	}



	if (!hba->dev_info.b_presrv_uspc_en) {

		if (avail_buf <= UFS_WB_10_PERCENT_BUF_REMAIN)

			return true;

		return false;

	}



	return ufshcd_wb_presrv_usrspc_keep_vcc_on(hba, avail_buf);

}



/**

 * ufshcd_exception_event_handler - handle exceptions raised by device

 * @work: pointer to work data
@@ -6603,6 +6798,33 @@ static int ufshcd_scsi_add_wlus(struct ufs_hba *hba) 
	return ret;

}



static void ufshcd_wb_probe(struct ufs_hba *hba, u8 *desc_buf)

{

	hba->dev_info.d_ext_ufs_feature_sup =

		get_unaligned_be32(desc_buf +

				   DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP);

	/*

	 * WB may be supported but not configured while provisioning.

	 * The spec says, in dedicated wb buffer mode,

	 * a max of 1 lun would have wb buffer configured.

	 * Now only shared buffer mode is supported.

	 */

	hba->dev_info.b_wb_buffer_type =

		desc_buf[DEVICE_DESC_PARAM_WB_TYPE];



	hba->dev_info.d_wb_alloc_units =

		get_unaligned_be32(desc_buf +

				   DEVICE_DESC_PARAM_WB_SHARED_ALLOC_UNITS);

	hba->dev_info.b_presrv_uspc_en =

		desc_buf[DEVICE_DESC_PARAM_WB_PRESRV_USRSPC_EN];



	if (!((hba->dev_info.d_ext_ufs_feature_sup &

		 UFS_DEV_WRITE_BOOSTER_SUP) &&

		hba->dev_info.b_wb_buffer_type &&

	      hba->dev_info.d_wb_alloc_units))

		hba->caps &= ~UFSHCD_CAP_WB_EN;

}



static int ufs_get_device_desc(struct ufs_hba *hba)

{

	int err;
@@ -6639,6 +6861,11 @@ static int ufs_get_device_desc(struct ufs_hba *hba) 
				      desc_buf[DEVICE_DESC_PARAM_SPEC_VER + 1];



	model_index = desc_buf[DEVICE_DESC_PARAM_PRDCT_NAME];



	/* Enable WB only for UFS-3.1 */

	if (dev_info->wspecversion >= 0x310)

		ufshcd_wb_probe(hba, desc_buf);



	err = ufshcd_read_string_desc(hba, model_index,

				      &dev_info->model, SD_ASCII_STD);

	if (err < 0) {
@@ -7149,6 +7376,7 @@ static int ufshcd_probe_hba(struct ufs_hba *hba, bool async) 
	/* set the state as operational after switching to desired gear */

	hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;



	ufshcd_wb_config(hba);

	/* Enable Auto-Hibernate if configured */

	ufshcd_auto_hibern8_enable(hba);
@@ -7809,11 +8037,15 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba *hba) 
	 *

	 * Ignore the error returned by ufshcd_toggle_vreg() as device is anyway

	 * in low power state which would save some power.

	 *

	 * If Write Booster is enabled and the device needs to flush the WB

	 * buffer OR if bkops status is urgent for WB, keep Vcc on.

	 */

	if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba) &&

	    !hba->dev_info.is_lu_power_on_wp) {

		ufshcd_setup_vreg(hba, false);

	} else if (!ufshcd_is_ufs_dev_active(hba)) {

		if (!hba->dev_info.keep_vcc_on)

			ufshcd_toggle_vreg(hba->dev, hba->vreg_info.vcc, false);

		if (!ufshcd_is_link_active(hba)) {

			ufshcd_config_vreg_lpm(hba, hba->vreg_info.vccq);
@@ -7938,6 +8170,18 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
			/* make sure that auto bkops is disabled */

			ufshcd_disable_auto_bkops(hba);

		}

		/*

		 * With wb enabled, if the bkops is enabled or if the

		 * configured WB type is 70% full, keep vcc ON

		 * for the device to flush the wb buffer

		 */

		if ((hba->auto_bkops_enabled && ufshcd_wb_sup(hba)) ||

		    ufshcd_wb_keep_vcc_on(hba))

			hba->dev_info.keep_vcc_on = true;

		else

			hba->dev_info.keep_vcc_on = false;

	} else if (!ufshcd_is_runtime_pm(pm_op)) {

		hba->dev_info.keep_vcc_on = false;

	}



	if ((req_dev_pwr_mode != hba->curr_dev_pwr_mode) &&

drivers/scsi/ufs/ufshcd.h

+14 −0
Original line number Diff line number Diff line
@@ -555,6 +555,13 @@ enum ufshcd_caps { 
	 * for userspace to control the power management.

	 */

	UFSHCD_CAP_RPM_AUTOSUSPEND			= 1 << 6,



	/*

	 * This capability allows the host controller driver to turn-on

	 * WriteBooster, if the underlying device supports it and is

	 * provisioned to be used. This would increase the write performance.

	 */

	UFSHCD_CAP_WB_EN				= 1 << 7,

};



/**
@@ -727,6 +734,8 @@ struct ufs_hba { 


	struct device		bsg_dev;

	struct request_queue	*bsg_queue;

	bool wb_buf_flush_enabled;

	bool wb_enabled;

};



/* Returns true if clocks can be gated. Otherwise false */
@@ -775,6 +784,11 @@ static inline bool ufshcd_is_auto_hibern8_enabled(struct ufs_hba *hba) 
	return FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, hba->ahit) ? true : false;

}



static inline bool ufshcd_is_wb_allowed(struct ufs_hba *hba)

{

	return hba->caps & UFSHCD_CAP_WB_EN;

}



#define ufshcd_writel(hba, val, reg)	\

	writel((val), (hba)->mmio_base + (reg))

#define ufshcd_readl(hba, reg)	\