ufs/core/ufs-mcq.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2022 Qualcomm Innovation Center. All rights reserved.
 *
 * Authors:
 *	Asutosh Das <quic_asutoshd@quicinc.com>
 *	Can Guo <quic_cang@quicinc.com>
 */

#include <linux/unaligned.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include "ufshcd-priv.h"
#include <linux/delay.h>
#include <scsi/scsi_cmnd.h>
#include <linux/bitfield.h>
#include <linux/iopoll.h>

#define MAX_QUEUE_SUP GENMASK(7, 0)
#define QCFGPTR GENMASK(23, 16)
#define UFS_MCQ_MIN_RW_QUEUES 2
#define UFS_MCQ_MIN_READ_QUEUES 0
#define UFS_MCQ_MIN_POLL_QUEUES 0
#define QUEUE_EN_OFFSET 31
#define QUEUE_ID_OFFSET 16

#define MCQ_CFG_MAC_MASK	GENMASK(16, 8)
#define MCQ_ENTRY_SIZE_IN_DWORD	8
#define CQE_UCD_BA GENMASK_ULL(63, 7)

#define UFSHCD_ENABLE_MCQ_INTRS	(UTP_TASK_REQ_COMPL |\
				 UFSHCD_ERROR_MASK |\
				 MCQ_CQ_EVENT_STATUS |\
				 MCQ_IAG_EVENT_STATUS)

/* Max mcq register polling time in microseconds */
#define MCQ_POLL_US 500000

static int rw_queue_count_set(const char *val, const struct kernel_param *kp)
{
	return param_set_uint_minmax(val, kp, UFS_MCQ_MIN_RW_QUEUES,
				     num_possible_cpus());
}

static const struct kernel_param_ops rw_queue_count_ops = {
	.set = rw_queue_count_set,
	.get = param_get_uint,
};

static unsigned int rw_queues;
module_param_cb(rw_queues, &rw_queue_count_ops, &rw_queues, 0644);
MODULE_PARM_DESC(rw_queues,
		 "Number of interrupt driven I/O queues used for rw. Default value is nr_cpus");

static int read_queue_count_set(const char *val, const struct kernel_param *kp)
{
	return param_set_uint_minmax(val, kp, UFS_MCQ_MIN_READ_QUEUES,
				     num_possible_cpus());
}

static const struct kernel_param_ops read_queue_count_ops = {
	.set = read_queue_count_set,
	.get = param_get_uint,
};

static unsigned int read_queues;
module_param_cb(read_queues, &read_queue_count_ops, &read_queues, 0644);
MODULE_PARM_DESC(read_queues,
		 "Number of interrupt driven read queues used for read. Default value is 0");

static int poll_queue_count_set(const char *val, const struct kernel_param *kp)
{
	return param_set_uint_minmax(val, kp, UFS_MCQ_MIN_POLL_QUEUES,
				     num_possible_cpus());
}

static const struct kernel_param_ops poll_queue_count_ops = {
	.set = poll_queue_count_set,
	.get = param_get_uint,
};

static unsigned int poll_queues = 1;
module_param_cb(poll_queues, &poll_queue_count_ops, &poll_queues, 0644);
MODULE_PARM_DESC(poll_queues,
		 "Number of poll queues used for r/w. Default value is 1");

/**
 * ufshcd_mcq_config_mac - Set the #Max Activ Cmds.
 * @hba: per adapter instance
 * @max_active_cmds: maximum # of active commands to the device at any time.
 *
 * The controller won't send more than the max_active_cmds to the device at
 * any time.
 */
void ufshcd_mcq_config_mac(struct ufs_hba *hba, u32 max_active_cmds)
{
	u32 val;

	val = ufshcd_readl(hba, REG_UFS_MCQ_CFG);
	val &= ~MCQ_CFG_MAC_MASK;
	val |= FIELD_PREP(MCQ_CFG_MAC_MASK, max_active_cmds - 1);
	ufshcd_writel(hba, val, REG_UFS_MCQ_CFG);
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_config_mac);

/**
 * ufshcd_mcq_req_to_hwq - find the hardware queue on which the
 * request would be issued.
 * @hba: per adapter instance
 * @req: pointer to the request to be issued
 *
 * Return: the hardware queue instance on which the request will be or has
 * been queued. %NULL if the request has already been freed.
 */
struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
					 struct request *req)
{
	struct blk_mq_hw_ctx *hctx = READ_ONCE(req->mq_hctx);

	return hctx ? &hba->uhq[hctx->queue_num] : NULL;
}

/**
 * ufshcd_mcq_queue_cfg_addr - get an start address of the MCQ Queue Config
 * Registers.
 * @hba: per adapter instance
 *
 * Return: Start address of MCQ Queue Config Registers in HCI
 */
unsigned int ufshcd_mcq_queue_cfg_addr(struct ufs_hba *hba)
{
	return FIELD_GET(QCFGPTR, hba->mcq_capabilities) * 0x200;
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_queue_cfg_addr);

/**
 * ufshcd_get_hba_mac - Maximum number of commands supported by the host
 *	controller.
 * @hba: per adapter instance
 *
 * Return: queue depth on success; negative upon error.
 *
 * MAC = Maximum number of Active Commands supported by the Host Controller.
 */
int ufshcd_get_hba_mac(struct ufs_hba *hba)
{
	int mac;

	if (!hba->vops || !hba->vops->get_hba_mac) {
		/*
		 * Extract the maximum number of active transfer tasks value
		 * from the host controller capabilities register. This value is
		 * 0-based.
		 */
		hba->capabilities =
			ufshcd_readl(hba, REG_CONTROLLER_CAPABILITIES);
		mac = hba->capabilities & MASK_TRANSFER_REQUESTS_SLOTS_MCQ;
		mac++;
	} else {
		mac = hba->vops->get_hba_mac(hba);
	}
	if (mac < 0)
		dev_err(hba->dev, "Failed to get mac, err=%d\n", mac);
	return mac;
}

static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
{
	int i;
	u32 hba_maxq, rem, tot_queues;
	struct Scsi_Host *host = hba->host;

	/* maxq is 0 based value */
	hba_maxq = FIELD_GET(MAX_QUEUE_SUP, hba->mcq_capabilities) + 1;

	tot_queues = read_queues + poll_queues + rw_queues;

	if (hba_maxq < tot_queues) {
		dev_err(hba->dev, "Total queues (%d) exceeds HC capacity (%d)\n",
			tot_queues, hba_maxq);
		return -EOPNOTSUPP;
	}

	/*
	 * Device should support at least one I/O queue to handle device
	 * commands via hba->dev_cmd_queue.
	 */
	if (hba_maxq == poll_queues) {
		dev_err(hba->dev, "At least one non-poll queue required\n");
		return -EOPNOTSUPP;
	}

	rem = hba_maxq;

	if (rw_queues) {
		hba->nr_queues[HCTX_TYPE_DEFAULT] = rw_queues;
		rem -= hba->nr_queues[HCTX_TYPE_DEFAULT];
	} else {
		rw_queues = num_possible_cpus();
	}

	if (poll_queues) {
		hba->nr_queues[HCTX_TYPE_POLL] = poll_queues;
		rem -= hba->nr_queues[HCTX_TYPE_POLL];
	}

	if (read_queues) {
		hba->nr_queues[HCTX_TYPE_READ] = read_queues;
		rem -= hba->nr_queues[HCTX_TYPE_READ];
	}

	if (!hba->nr_queues[HCTX_TYPE_DEFAULT])
		hba->nr_queues[HCTX_TYPE_DEFAULT] = min3(rem, rw_queues,
							 num_possible_cpus());

	for (i = 0; i < HCTX_MAX_TYPES; i++)
		host->nr_hw_queues += hba->nr_queues[i];

	hba->nr_hw_queues = host->nr_hw_queues;
	return 0;
}

int ufshcd_mcq_memory_alloc(struct ufs_hba *hba)
{
	struct ufs_hw_queue *hwq;
	size_t utrdl_size, cqe_size;
	int i;

	for (i = 0; i < hba->nr_hw_queues; i++) {
		hwq = &hba->uhq[i];

		utrdl_size = sizeof(struct utp_transfer_req_desc) *
			     hwq->max_entries;
		hwq->sqe_base_addr = dmam_alloc_coherent(hba->dev, utrdl_size,
							 &hwq->sqe_dma_addr,
							 GFP_KERNEL);
		if (!hwq->sqe_base_addr) {
			dev_err(hba->dev, "SQE allocation failed\n");
			return -ENOMEM;
		}

		cqe_size = sizeof(struct cq_entry) * hwq->max_entries;
		hwq->cqe_base_addr = dmam_alloc_coherent(hba->dev, cqe_size,
							 &hwq->cqe_dma_addr,
							 GFP_KERNEL);
		if (!hwq->cqe_base_addr) {
			dev_err(hba->dev, "CQE allocation failed\n");
			return -ENOMEM;
		}
	}

	return 0;
}

static void __iomem *mcq_opr_base(struct ufs_hba *hba,
					 enum ufshcd_mcq_opr n, int i)
{
	struct ufshcd_mcq_opr_info_t *opr = &hba->mcq_opr[n];

	return opr->base + opr->stride * i;
}

u32 ufshcd_mcq_read_cqis(struct ufs_hba *hba, int i)
{
	return readl(mcq_opr_base(hba, OPR_CQIS, i) + REG_CQIS);
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_read_cqis);

void ufshcd_mcq_write_cqis(struct ufs_hba *hba, u32 val, int i)
{
	writel(val, mcq_opr_base(hba, OPR_CQIS, i) + REG_CQIS);
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_write_cqis);

u32 ufshcd_mcq_read_mcqiacr(struct ufs_hba *hba, int i)
{
	return readl(mcq_opr_base(hba, OPR_CQIS, i) + REG_MCQIACR);
}

void ufshcd_mcq_write_mcqiacr(struct ufs_hba *hba, u32 val, int i)
{
	writel(val, mcq_opr_base(hba, OPR_CQIS, i) + REG_MCQIACR);
}

/*
 * UFSHCI 4.0 MCQ specification doesn't provide a Task Tag or its equivalent in
 * the Completion Queue Entry. Find the Task Tag using an indirect method.
 * UFSHCI 4.1 and above can directly return the Task Tag in the Completion Queue
 * Entry.
 */
static int ufshcd_mcq_get_tag(struct ufs_hba *hba, struct cq_entry *cqe)
{
	u64 addr;

	if (hba->ufs_version >= ufshci_version(4, 1))
		return cqe->task_tag;

	/* sizeof(struct utp_transfer_cmd_desc) must be a multiple of 128 */
	BUILD_BUG_ON(sizeof(struct utp_transfer_cmd_desc) & GENMASK(6, 0));

	/* Bits 63:7 UCD base address, 6:5 are reserved, 4:0 is SQ ID */
	addr = (le64_to_cpu(cqe->command_desc_base_addr) & CQE_UCD_BA) -
		hba->ucdl_dma_addr;

	return div_u64(addr, ufshcd_get_ucd_size(hba));
}

static void ufshcd_mcq_process_cqe(struct ufs_hba *hba,
				   struct ufs_hw_queue *hwq)
{
	struct cq_entry *cqe = ufshcd_mcq_cur_cqe(hwq);

	if (cqe->command_desc_base_addr) {
		int tag = ufshcd_mcq_get_tag(hba, cqe);

		ufshcd_compl_one_cqe(hba, tag, cqe);
		/* After processed the cqe, mark it empty (invalid) entry */
		cqe->command_desc_base_addr = 0;
	} else {
		dev_err(hba->dev, "Abnormal CQ entry!\n");
	}
}

/*
 * This function is called from the UFS error handler with the UFS host
 * controller disabled (HCE = 0). Reading host controller registers, e.g. the
 * CQ tail pointer (CQTPy), may not be safe with the host controller disabled.
 * Hence, iterate over all completion queue entries. This won't result in
 * double completions because ufshcd_mcq_process_cqe() clears a CQE after it
 * has been processed.
 */
void ufshcd_mcq_compl_all_cqes_lock(struct ufs_hba *hba,
				    struct ufs_hw_queue *hwq)
{
	unsigned long flags;
	u32 entries = hwq->max_entries;

	spin_lock_irqsave(&hwq->cq_lock, flags);
	while (entries > 0) {
		ufshcd_mcq_process_cqe(hba, hwq);
		ufshcd_mcq_inc_cq_head_slot(hwq);
		entries--;
	}

	ufshcd_mcq_update_cq_tail_slot(hwq);
	hwq->cq_head_slot = hwq->cq_tail_slot;
	spin_unlock_irqrestore(&hwq->cq_lock, flags);
}

unsigned long ufshcd_mcq_poll_cqe_lock(struct ufs_hba *hba,
				       struct ufs_hw_queue *hwq)
{
	unsigned long completed_reqs = 0;
	unsigned long flags;

	spin_lock_irqsave(&hwq->cq_lock, flags);
	ufshcd_mcq_update_cq_tail_slot(hwq);
	while (!ufshcd_mcq_is_cq_empty(hwq)) {
		ufshcd_mcq_process_cqe(hba, hwq);
		ufshcd_mcq_inc_cq_head_slot(hwq);
		completed_reqs++;
	}

	if (completed_reqs)
		ufshcd_mcq_update_cq_head(hwq);
	spin_unlock_irqrestore(&hwq->cq_lock, flags);

	return completed_reqs;
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_poll_cqe_lock);

void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba)
{
	struct ufs_hw_queue *hwq;
	u32 intrs;
	u16 qsize;
	int i;

	/* Enable required interrupts */
	intrs = UFSHCD_ENABLE_MCQ_INTRS;
	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_INTR)
		intrs &= ~MCQ_CQ_EVENT_STATUS;
	ufshcd_enable_intr(hba, intrs);

	for (i = 0; i < hba->nr_hw_queues; i++) {
		hwq = &hba->uhq[i];
		hwq->id = i;
		qsize = hwq->max_entries * MCQ_ENTRY_SIZE_IN_DWORD - 1;

		/* Submission Queue Lower Base Address */
		ufsmcq_writelx(hba, lower_32_bits(hwq->sqe_dma_addr),
			      ufshcd_mcq_cfg_offset(REG_SQLBA, i));
		/* Submission Queue Upper Base Address */
		ufsmcq_writelx(hba, upper_32_bits(hwq->sqe_dma_addr),
			      ufshcd_mcq_cfg_offset(REG_SQUBA, i));
		/* Submission Queue Doorbell Address Offset */
		ufsmcq_writelx(hba, ufshcd_mcq_opr_offset(hba, OPR_SQD, i),
			      ufshcd_mcq_cfg_offset(REG_SQDAO, i));
		/* Submission Queue Interrupt Status Address Offset */
		ufsmcq_writelx(hba, ufshcd_mcq_opr_offset(hba, OPR_SQIS, i),
			      ufshcd_mcq_cfg_offset(REG_SQISAO, i));

		/* Completion Queue Lower Base Address */
		ufsmcq_writelx(hba, lower_32_bits(hwq->cqe_dma_addr),
			      ufshcd_mcq_cfg_offset(REG_CQLBA, i));
		/* Completion Queue Upper Base Address */
		ufsmcq_writelx(hba, upper_32_bits(hwq->cqe_dma_addr),
			      ufshcd_mcq_cfg_offset(REG_CQUBA, i));
		/* Completion Queue Doorbell Address Offset */
		ufsmcq_writelx(hba, ufshcd_mcq_opr_offset(hba, OPR_CQD, i),
			      ufshcd_mcq_cfg_offset(REG_CQDAO, i));
		/* Completion Queue Interrupt Status Address Offset */
		ufsmcq_writelx(hba, ufshcd_mcq_opr_offset(hba, OPR_CQIS, i),
			      ufshcd_mcq_cfg_offset(REG_CQISAO, i));

		/* Save the base addresses for quicker access */
		hwq->mcq_sq_head = mcq_opr_base(hba, OPR_SQD, i) + REG_SQHP;
		hwq->mcq_sq_tail = mcq_opr_base(hba, OPR_SQD, i) + REG_SQTP;
		hwq->mcq_cq_head = mcq_opr_base(hba, OPR_CQD, i) + REG_CQHP;
		hwq->mcq_cq_tail = mcq_opr_base(hba, OPR_CQD, i) + REG_CQTP;

		/* Reinitializing is needed upon HC reset */
		hwq->sq_tail_slot = hwq->cq_tail_slot = hwq->cq_head_slot = 0;

		/* Enable Tail Entry Push Status interrupt only for non-poll queues */
		if (i < hba->nr_hw_queues - hba->nr_queues[HCTX_TYPE_POLL])
			writel(1, mcq_opr_base(hba, OPR_CQIS, i) + REG_CQIE);

		/* Completion Queue Enable|Size to Completion Queue Attribute */
		ufsmcq_writel(hba, (1 << QUEUE_EN_OFFSET) | qsize,
			      ufshcd_mcq_cfg_offset(REG_CQATTR, i));

		/*
		 * Submission Qeueue Enable|Size|Completion Queue ID to
		 * Submission Queue Attribute
		 */
		ufsmcq_writel(hba, (1 << QUEUE_EN_OFFSET) | qsize |
			      (i << QUEUE_ID_OFFSET),
			      ufshcd_mcq_cfg_offset(REG_SQATTR, i));
	}
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_make_queues_operational);

void ufshcd_mcq_enable(struct ufs_hba *hba)
{
	ufshcd_rmwl(hba, MCQ_MODE_SELECT, MCQ_MODE_SELECT, REG_UFS_MEM_CFG);
	hba->mcq_enabled = true;
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_enable);

void ufshcd_mcq_disable(struct ufs_hba *hba)
{
	ufshcd_rmwl(hba, MCQ_MODE_SELECT, 0, REG_UFS_MEM_CFG);
	hba->mcq_enabled = false;
}

void ufshcd_mcq_enable_esi(struct ufs_hba *hba)
{
	ufshcd_rmwl(hba, ESI_ENABLE, ESI_ENABLE, REG_UFS_MEM_CFG);
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_enable_esi);

void ufshcd_mcq_config_esi(struct ufs_hba *hba, struct msi_msg *msg)
{
	ufshcd_writel(hba, msg->address_lo, REG_UFS_ESILBA);
	ufshcd_writel(hba, msg->address_hi, REG_UFS_ESIUBA);
}
EXPORT_SYMBOL_GPL(ufshcd_mcq_config_esi);

int ufshcd_mcq_init(struct ufs_hba *hba)
{
	struct ufs_hw_queue *hwq;
	int ret, i;

	ret = ufshcd_mcq_config_nr_queues(hba);
	if (ret)
		return ret;

	ret = ufshcd_vops_mcq_config_resource(hba);
	if (ret)
		return ret;

	ret = ufshcd_mcq_vops_op_runtime_config(hba);
	if (ret) {
		dev_err(hba->dev, "Operation runtime config failed, ret=%d\n",
			ret);
		return ret;
	}
	hba->uhq = devm_kzalloc(hba->dev,
				hba->nr_hw_queues * sizeof(struct ufs_hw_queue),
				GFP_KERNEL);
	if (!hba->uhq) {
		dev_err(hba->dev, "ufs hw queue memory allocation failed\n");
		return -ENOMEM;
	}

	for (i = 0; i < hba->nr_hw_queues; i++) {
		hwq = &hba->uhq[i];
		hwq->max_entries = hba->nutrs + 1;
		spin_lock_init(&hwq->sq_lock);
		spin_lock_init(&hwq->cq_lock);
		mutex_init(&hwq->sq_mutex);
	}

	return 0;
}

static int ufshcd_mcq_sq_stop(struct ufs_hba *hba, struct ufs_hw_queue *hwq)
{
	void __iomem *reg;
	u32 id = hwq->id, val;
	int err;

	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_RTC)
		return -ETIMEDOUT;

	writel(SQ_STOP, mcq_opr_base(hba, OPR_SQD, id) + REG_SQRTC);
	reg = mcq_opr_base(hba, OPR_SQD, id) + REG_SQRTS;
	err = read_poll_timeout(readl, val, val & SQ_STS, 20,
				MCQ_POLL_US, false, reg);
	if (err)
		dev_err(hba->dev, "%s: failed. hwq-id=%d, err=%d\n",
			__func__, id, err);
	return err;
}

static int ufshcd_mcq_sq_start(struct ufs_hba *hba, struct ufs_hw_queue *hwq)
{
	void __iomem *reg;
	u32 id = hwq->id, val;
	int err;

	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_RTC)
		return -ETIMEDOUT;

	writel(SQ_START, mcq_opr_base(hba, OPR_SQD, id) + REG_SQRTC);
	reg = mcq_opr_base(hba, OPR_SQD, id) + REG_SQRTS;
	err = read_poll_timeout(readl, val, !(val & SQ_STS), 20,
				MCQ_POLL_US, false, reg);
	if (err)
		dev_err(hba->dev, "%s: failed. hwq-id=%d, err=%d\n",
			__func__, id, err);
	return err;
}

/**
 * ufshcd_mcq_sq_cleanup - Clean up submission queue resources
 * associated with the pending command.
 * @hba: per adapter instance.
 * @task_tag: The command's task tag.
 *
 * Return: 0 for success; error code otherwise.
 */
int ufshcd_mcq_sq_cleanup(struct ufs_hba *hba, int task_tag)
{
	struct scsi_cmnd *cmd = ufshcd_tag_to_cmd(hba, task_tag);
	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
	struct request *rq = scsi_cmd_to_rq(cmd);
	struct ufs_hw_queue *hwq;
	void __iomem *reg, *opr_sqd_base;
	u32 nexus, id, val;
	int err;

	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_RTC)
		return -ETIMEDOUT;

	if (!cmd)
		return -EINVAL;

	hwq = ufshcd_mcq_req_to_hwq(hba, rq);
	if (!hwq)
		return 0;

	id = hwq->id;

	guard(mutex)(&hwq->sq_mutex);

	/* stop the SQ fetching before working on it */
	err = ufshcd_mcq_sq_stop(hba, hwq);
	if (err)
		return err;

	/* SQCTI = EXT_IID, IID, LUN, Task Tag */
	nexus = lrbp->lun << 8 | task_tag;
	opr_sqd_base = mcq_opr_base(hba, OPR_SQD, id);
	writel(nexus, opr_sqd_base + REG_SQCTI);

	/* Initiate Cleanup */
	writel(readl(opr_sqd_base + REG_SQRTC) | SQ_ICU,
		opr_sqd_base + REG_SQRTC);

	/* Wait until SQRTSy.CUS = 1. Report SQRTSy.RTC. */
	reg = opr_sqd_base + REG_SQRTS;
	err = read_poll_timeout(readl, val, val & SQ_CUS, 20,
				MCQ_POLL_US, false, reg);
	if (err)
		dev_err(hba->dev, "%s: failed. hwq=%d, tag=%d err=%d\n",
			__func__, id, task_tag, err);
	else
		dev_info(hba->dev,
			 "%s, hwq %d: cleanup return code (RTC) %ld\n",
			 __func__, id,
			 FIELD_GET(SQ_ICU_ERR_CODE_MASK, readl(reg)));

	if (ufshcd_mcq_sq_start(hba, hwq))
		err = -ETIMEDOUT;

	return err;
}

/**
 * ufshcd_mcq_nullify_sqe - Nullify the submission queue entry.
 * Write the sqe's Command Type to 0xF. The host controller will not
 * fetch any sqe with Command Type = 0xF.
 *
 * @utrd: UTP Transfer Request Descriptor to be nullified.
 */
static void ufshcd_mcq_nullify_sqe(struct utp_transfer_req_desc *utrd)
{
	utrd->header.command_type = 0xf;
}

/**
 * ufshcd_mcq_sqe_search - Search for the command in the submission queue
 * If the command is in the submission queue and not issued to the device yet,
 * nullify the sqe so the host controller will skip fetching the sqe.
 *
 * @hba: per adapter instance.
 * @hwq: Hardware Queue to be searched.
 * @task_tag: The command's task tag.
 *
 * Return: true if the SQE containing the command is present in the SQ
 * (not fetched by the controller); returns false if the SQE is not in the SQ.
 */
static bool ufshcd_mcq_sqe_search(struct ufs_hba *hba,
				  struct ufs_hw_queue *hwq, int task_tag)
{
	struct scsi_cmnd *cmd = ufshcd_tag_to_cmd(hba, task_tag);
	struct ufshcd_lrb *lrbp;
	struct utp_transfer_req_desc *utrd;
	__le64  cmd_desc_base_addr;
	bool ret = false;
	u64 addr, match;
	u32 sq_head_slot;

	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_RTC)
		return true;

	if (!cmd)
		return false;

	lrbp = scsi_cmd_priv(cmd);

	mutex_lock(&hwq->sq_mutex);

	ufshcd_mcq_sq_stop(hba, hwq);
	sq_head_slot = ufshcd_mcq_get_sq_head_slot(hwq);
	if (sq_head_slot == hwq->sq_tail_slot)
		goto out;

	cmd_desc_base_addr = lrbp->utr_descriptor_ptr->command_desc_base_addr;
	addr = le64_to_cpu(cmd_desc_base_addr) & CQE_UCD_BA;

	while (sq_head_slot != hwq->sq_tail_slot) {
		utrd = hwq->sqe_base_addr + sq_head_slot;
		match = le64_to_cpu(utrd->command_desc_base_addr) & CQE_UCD_BA;
		if (addr == match) {
			ufshcd_mcq_nullify_sqe(utrd);
			ret = true;
			goto out;
		}

		sq_head_slot++;
		if (sq_head_slot == hwq->max_entries)
			sq_head_slot = 0;
	}

out:
	ufshcd_mcq_sq_start(hba, hwq);
	mutex_unlock(&hwq->sq_mutex);
	return ret;
}

/**
 * ufshcd_mcq_abort - Abort the command in MCQ.
 * @cmd: The command to be aborted.
 *
 * Return: SUCCESS or FAILED error codes
 */
int ufshcd_mcq_abort(struct scsi_cmnd *cmd)
{
	struct Scsi_Host *host = cmd->device->host;
	struct ufs_hba *hba = shost_priv(host);
	int tag = scsi_cmd_to_rq(cmd)->tag;
	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
	struct ufs_hw_queue *hwq;
	int err;

	/* Skip task abort in case previous aborts failed and report failure */
	if (lrbp->req_abort_skip) {
		dev_err(hba->dev, "%s: skip abort. tag %d failed earlier\n",
			__func__, tag);
		return FAILED;
	}

	hwq = ufshcd_mcq_req_to_hwq(hba, scsi_cmd_to_rq(cmd));
	if (!hwq) {
		dev_err(hba->dev, "%s: skip abort. cmd at tag %d already completed.\n",
			__func__, tag);
		return FAILED;
	}

	if (ufshcd_mcq_sqe_search(hba, hwq, tag)) {
		/*
		 * Failure. The command should not be "stuck" in SQ for
		 * a long time which resulted in command being aborted.
		 */
		dev_err(hba->dev, "%s: cmd found in sq. hwq=%d, tag=%d\n",
			__func__, hwq->id, tag);
		return FAILED;
	}

	/*
	 * The command is not in the submission queue, and it is not
	 * in the completion queue either. Query the device to see if
	 * the command is being processed in the device.
	 */
	err = ufshcd_try_to_abort_task(hba, tag);
	if (err) {
		dev_err(hba->dev, "%s: device abort failed %d\n", __func__, err);
		lrbp->req_abort_skip = true;
		return FAILED;
	}

	return SUCCESS;
}