linux/drivers/slimbus/qcom-ctrl.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2011-2017, The Linux Foundation
 */

#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/pm_runtime.h>
#include "slimbus.h"

/* Manager registers */
#define	MGR_CFG		0x200
#define	MGR_STATUS	0x204
#define	MGR_INT_EN	0x210
#define	MGR_INT_STAT	0x214
#define	MGR_INT_CLR	0x218
#define	MGR_TX_MSG	0x230
#define	MGR_RX_MSG	0x270
#define	MGR_IE_STAT	0x2F0
#define	MGR_VE_STAT	0x300
#define	MGR_CFG_ENABLE	1

/* Framer registers */
#define	FRM_CFG		0x400
#define	FRM_STAT	0x404
#define	FRM_INT_EN	0x410
#define	FRM_INT_STAT	0x414
#define	FRM_INT_CLR	0x418
#define	FRM_WAKEUP	0x41C
#define	FRM_CLKCTL_DONE	0x420
#define	FRM_IE_STAT	0x430
#define	FRM_VE_STAT	0x440

/* Interface registers */
#define	INTF_CFG	0x600
#define	INTF_STAT	0x604
#define	INTF_INT_EN	0x610
#define	INTF_INT_STAT	0x614
#define	INTF_INT_CLR	0x618
#define	INTF_IE_STAT	0x630
#define	INTF_VE_STAT	0x640

/* Interrupt status bits */
#define	MGR_INT_TX_NACKED_2	BIT(25)
#define	MGR_INT_MSG_BUF_CONTE	BIT(26)
#define	MGR_INT_RX_MSG_RCVD	BIT(30)
#define	MGR_INT_TX_MSG_SENT	BIT(31)

/* Framer config register settings */
#define	FRM_ACTIVE	1
#define	CLK_GEAR	7
#define	ROOT_FREQ	11
#define	REF_CLK_GEAR	15
#define	INTR_WAKE	19

#define SLIM_MSG_ASM_FIRST_WORD(l, mt, mc, dt, ad) \
		((l) | ((mt) << 5) | ((mc) << 8) | ((dt) << 15) | ((ad) << 16))

#define SLIM_ROOT_FREQ 24576000
#define QCOM_SLIM_AUTOSUSPEND 1000

/* MAX message size over control channel */
#define SLIM_MSGQ_BUF_LEN	40
#define QCOM_TX_MSGS 2
#define QCOM_RX_MSGS	8
#define QCOM_BUF_ALLOC_RETRIES	10

#define CFG_PORT(r, v) ((v) ? CFG_PORT_V2(r) : CFG_PORT_V1(r))

/* V2 Component registers */
#define CFG_PORT_V2(r) ((r ## _V2))
#define	COMP_CFG_V2		4
#define	COMP_TRUST_CFG_V2	0x3000

/* V1 Component registers */
#define CFG_PORT_V1(r) ((r ## _V1))
#define	COMP_CFG_V1		0
#define	COMP_TRUST_CFG_V1	0x14

/* Resource group info for manager, and non-ported generic device-components */
#define EE_MGR_RSC_GRP	(1 << 10)
#define EE_NGD_2	(2 << 6)
#define EE_NGD_1	0

struct slim_ctrl_buf {
	void		*base;
	spinlock_t	lock;
	int		head;
	int		tail;
	int		sl_sz;
	int		n;
};

struct qcom_slim_ctrl {
	struct slim_controller  ctrl;
	struct slim_framer	framer;
	struct device		*dev;
	void __iomem		*base;
	void __iomem		*slew_reg;

	struct slim_ctrl_buf	rx;
	struct slim_ctrl_buf	tx;

	struct completion	**wr_comp;
	int			irq;
	struct workqueue_struct *rxwq;
	struct work_struct	wd;
	struct clk		*rclk;
	struct clk		*hclk;
};

static void qcom_slim_queue_tx(struct qcom_slim_ctrl *ctrl, void *buf,
			       u8 len, u32 tx_reg)
{
	int count = (len + 3) >> 2;

	__iowrite32_copy(ctrl->base + tx_reg, buf, count);

	/* Ensure Oder of subsequent writes */
	mb();
}

static void *slim_alloc_rxbuf(struct qcom_slim_ctrl *ctrl)
{
	unsigned long flags;
	int idx;

	spin_lock_irqsave(&ctrl->rx.lock, flags);
	if ((ctrl->rx.tail + 1) % ctrl->rx.n == ctrl->rx.head) {
		spin_unlock_irqrestore(&ctrl->rx.lock, flags);
		dev_err(ctrl->dev, "RX QUEUE full!");
		return NULL;
	}
	idx = ctrl->rx.tail;
	ctrl->rx.tail = (ctrl->rx.tail + 1) % ctrl->rx.n;
	spin_unlock_irqrestore(&ctrl->rx.lock, flags);

	return ctrl->rx.base + (idx * ctrl->rx.sl_sz);
}

static void slim_ack_txn(struct qcom_slim_ctrl *ctrl, int err)
{
	struct completion *comp;
	unsigned long flags;
	int idx;

	spin_lock_irqsave(&ctrl->tx.lock, flags);
	idx = ctrl->tx.head;
	ctrl->tx.head = (ctrl->tx.head + 1) % ctrl->tx.n;
	spin_unlock_irqrestore(&ctrl->tx.lock, flags);

	comp = ctrl->wr_comp[idx];
	ctrl->wr_comp[idx] = NULL;

	complete(comp);
}

static irqreturn_t qcom_slim_handle_tx_irq(struct qcom_slim_ctrl *ctrl,
					   u32 stat)
{
	int err = 0;

	if (stat & MGR_INT_TX_MSG_SENT)
		writel_relaxed(MGR_INT_TX_MSG_SENT,
			       ctrl->base + MGR_INT_CLR);

	if (stat & MGR_INT_TX_NACKED_2) {
		u32 mgr_stat = readl_relaxed(ctrl->base + MGR_STATUS);
		u32 mgr_ie_stat = readl_relaxed(ctrl->base + MGR_IE_STAT);
		u32 frm_stat = readl_relaxed(ctrl->base + FRM_STAT);
		u32 frm_cfg = readl_relaxed(ctrl->base + FRM_CFG);
		u32 frm_intr_stat = readl_relaxed(ctrl->base + FRM_INT_STAT);
		u32 frm_ie_stat = readl_relaxed(ctrl->base + FRM_IE_STAT);
		u32 intf_stat = readl_relaxed(ctrl->base + INTF_STAT);
		u32 intf_intr_stat = readl_relaxed(ctrl->base + INTF_INT_STAT);
		u32 intf_ie_stat = readl_relaxed(ctrl->base + INTF_IE_STAT);

		writel_relaxed(MGR_INT_TX_NACKED_2, ctrl->base + MGR_INT_CLR);

		dev_err(ctrl->dev, "TX Nack MGR:int:0x%x, stat:0x%x\n",
			stat, mgr_stat);
		dev_err(ctrl->dev, "TX Nack MGR:ie:0x%x\n", mgr_ie_stat);
		dev_err(ctrl->dev, "TX Nack FRM:int:0x%x, stat:0x%x\n",
			frm_intr_stat, frm_stat);
		dev_err(ctrl->dev, "TX Nack FRM:cfg:0x%x, ie:0x%x\n",
			frm_cfg, frm_ie_stat);
		dev_err(ctrl->dev, "TX Nack INTF:intr:0x%x, stat:0x%x\n",
			intf_intr_stat, intf_stat);
		dev_err(ctrl->dev, "TX Nack INTF:ie:0x%x\n",
			intf_ie_stat);
		err = -ENOTCONN;
	}

	slim_ack_txn(ctrl, err);

	return IRQ_HANDLED;
}

static irqreturn_t qcom_slim_handle_rx_irq(struct qcom_slim_ctrl *ctrl,
					   u32 stat)
{
	u32 *rx_buf, pkt[10];
	bool q_rx = false;
	u8 mc, mt, len;

	pkt[0] = readl_relaxed(ctrl->base + MGR_RX_MSG);
	mt = SLIM_HEADER_GET_MT(pkt[0]);
	len = SLIM_HEADER_GET_RL(pkt[0]);
	mc = SLIM_HEADER_GET_MC(pkt[0]>>8);

	/*
	 * this message cannot be handled by ISR, so
	 * let work-queue handle it
	 */
	if (mt == SLIM_MSG_MT_CORE && mc == SLIM_MSG_MC_REPORT_PRESENT) {
		rx_buf = (u32 *)slim_alloc_rxbuf(ctrl);
		if (!rx_buf) {
			dev_err(ctrl->dev, "dropping RX:0x%x due to RX full\n",
					pkt[0]);
			goto rx_ret_irq;
		}
		rx_buf[0] = pkt[0];

	} else {
		rx_buf = pkt;
	}

	__ioread32_copy(rx_buf + 1, ctrl->base + MGR_RX_MSG + 4,
			DIV_ROUND_UP(len, 4));

	switch (mc) {

	case SLIM_MSG_MC_REPORT_PRESENT:
		q_rx = true;
		break;
	case SLIM_MSG_MC_REPLY_INFORMATION:
	case SLIM_MSG_MC_REPLY_VALUE:
		slim_msg_response(&ctrl->ctrl, (u8 *)(rx_buf + 1),
				  (u8)(*rx_buf >> 24), (len - 4));
		break;
	default:
		dev_err(ctrl->dev, "unsupported MC,%x MT:%x\n",
			mc, mt);
		break;
	}
rx_ret_irq:
	writel(MGR_INT_RX_MSG_RCVD, ctrl->base +
		       MGR_INT_CLR);
	if (q_rx)
		queue_work(ctrl->rxwq, &ctrl->wd);

	return IRQ_HANDLED;
}

static irqreturn_t qcom_slim_interrupt(int irq, void *d)
{
	struct qcom_slim_ctrl *ctrl = d;
	u32 stat = readl_relaxed(ctrl->base + MGR_INT_STAT);
	int ret = IRQ_NONE;

	if (stat & MGR_INT_TX_MSG_SENT || stat & MGR_INT_TX_NACKED_2)
		ret = qcom_slim_handle_tx_irq(ctrl, stat);

	if (stat & MGR_INT_RX_MSG_RCVD)
		ret = qcom_slim_handle_rx_irq(ctrl, stat);

	return ret;
}

static int qcom_clk_pause_wakeup(struct slim_controller *sctrl)
{
	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(sctrl->dev);

	clk_prepare_enable(ctrl->hclk);
	clk_prepare_enable(ctrl->rclk);
	enable_irq(ctrl->irq);

	writel_relaxed(1, ctrl->base + FRM_WAKEUP);
	/* Make sure framer wakeup write goes through before ISR fires */
	mb();
	/*
	 * HW Workaround: Currently, slave is reporting lost-sync messages
	 * after SLIMbus comes out of clock pause.
	 * Transaction with slave fail before slave reports that message
	 * Give some time for that report to come
	 * SLIMbus wakes up in clock gear 10 at 24.576MHz. With each superframe
	 * being 250 usecs, we wait for 5-10 superframes here to ensure
	 * we get the message
	 */
	usleep_range(1250, 2500);
	return 0;
}

static void *slim_alloc_txbuf(struct qcom_slim_ctrl *ctrl,
			      struct slim_msg_txn *txn,
			      struct completion *done)
{
	unsigned long flags;
	int idx;

	spin_lock_irqsave(&ctrl->tx.lock, flags);
	if (((ctrl->tx.head + 1) % ctrl->tx.n) == ctrl->tx.tail) {
		spin_unlock_irqrestore(&ctrl->tx.lock, flags);
		dev_err(ctrl->dev, "controller TX buf unavailable");
		return NULL;
	}
	idx = ctrl->tx.tail;
	ctrl->wr_comp[idx] = done;
	ctrl->tx.tail = (ctrl->tx.tail + 1) % ctrl->tx.n;

	spin_unlock_irqrestore(&ctrl->tx.lock, flags);

	return ctrl->tx.base + (idx * ctrl->tx.sl_sz);
}


static int qcom_xfer_msg(struct slim_controller *sctrl,
			 struct slim_msg_txn *txn)
{
	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(sctrl->dev);
	DECLARE_COMPLETION_ONSTACK(done);
	void *pbuf = slim_alloc_txbuf(ctrl, txn, &done);
	unsigned long ms = txn->rl + HZ;
	u8 *puc;
	int ret = 0, timeout, retries = QCOM_BUF_ALLOC_RETRIES;
	u8 la = txn->la;
	u32 *head;
	/* HW expects length field to be excluded */
	txn->rl--;

	/* spin till buffer is made available */
	if (!pbuf) {
		while (retries--) {
			usleep_range(10000, 15000);
			pbuf = slim_alloc_txbuf(ctrl, txn, &done);
			if (pbuf)
				break;
		}
	}

	if (retries < 0 && !pbuf)
		return -ENOMEM;

	puc = (u8 *)pbuf;
	head = (u32 *)pbuf;

	if (txn->dt == SLIM_MSG_DEST_LOGICALADDR) {
		*head = SLIM_MSG_ASM_FIRST_WORD(txn->rl, txn->mt,
						txn->mc, 0, la);
		puc += 3;
	} else {
		*head = SLIM_MSG_ASM_FIRST_WORD(txn->rl, txn->mt,
						txn->mc, 1, la);
		puc += 2;
	}

	if (slim_tid_txn(txn->mt, txn->mc))
		*(puc++) = txn->tid;

	if (slim_ec_txn(txn->mt, txn->mc)) {
		*(puc++) = (txn->ec & 0xFF);
		*(puc++) = (txn->ec >> 8) & 0xFF;
	}

	if (txn->msg && txn->msg->wbuf)
		memcpy(puc, txn->msg->wbuf, txn->msg->num_bytes);

	qcom_slim_queue_tx(ctrl, head, txn->rl, MGR_TX_MSG);
	timeout = wait_for_completion_timeout(&done, msecs_to_jiffies(ms));

	if (!timeout) {
		dev_err(ctrl->dev, "TX timed out:MC:0x%x,mt:0x%x", txn->mc,
					txn->mt);
		ret = -ETIMEDOUT;
	}

	return ret;

}

static int qcom_set_laddr(struct slim_controller *sctrl,
				struct slim_eaddr *ead, u8 laddr)
{
	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(sctrl->dev);
	struct {
		__be16 manf_id;
		__be16 prod_code;
		u8 dev_index;
		u8 instance;
		u8 laddr;
	} __packed p;
	struct slim_val_inf msg = {0};
	DEFINE_SLIM_EDEST_TXN(txn, SLIM_MSG_MC_ASSIGN_LOGICAL_ADDRESS,
			      10, laddr, &msg);
	int ret;

	p.manf_id = cpu_to_be16(ead->manf_id);
	p.prod_code = cpu_to_be16(ead->prod_code);
	p.dev_index = ead->dev_index;
	p.instance = ead->instance;
	p.laddr = laddr;

	msg.wbuf = (void *)&p;
	msg.num_bytes = 7;
	ret = slim_do_transfer(&ctrl->ctrl, &txn);

	if (ret)
		dev_err(ctrl->dev, "set LA:0x%x failed:ret:%d\n",
				  laddr, ret);
	return ret;
}

static int slim_get_current_rxbuf(struct qcom_slim_ctrl *ctrl, void *buf)
{
	unsigned long flags;

	spin_lock_irqsave(&ctrl->rx.lock, flags);
	if (ctrl->rx.tail == ctrl->rx.head) {
		spin_unlock_irqrestore(&ctrl->rx.lock, flags);
		return -ENODATA;
	}
	memcpy(buf, ctrl->rx.base + (ctrl->rx.head * ctrl->rx.sl_sz),
				ctrl->rx.sl_sz);

	ctrl->rx.head = (ctrl->rx.head + 1) % ctrl->rx.n;
	spin_unlock_irqrestore(&ctrl->rx.lock, flags);

	return 0;
}

static void qcom_slim_rxwq(struct work_struct *work)
{
	u8 buf[SLIM_MSGQ_BUF_LEN];
	u8 mc, mt;
	int ret;
	struct qcom_slim_ctrl *ctrl = container_of(work, struct qcom_slim_ctrl,
						 wd);

	while ((slim_get_current_rxbuf(ctrl, buf)) != -ENODATA) {
		mt = SLIM_HEADER_GET_MT(buf[0]);
		mc = SLIM_HEADER_GET_MC(buf[1]);
		if (mt == SLIM_MSG_MT_CORE &&
			mc == SLIM_MSG_MC_REPORT_PRESENT) {
			struct slim_eaddr ea;
			u8 laddr;

			ea.manf_id = be16_to_cpup((__be16 *)&buf[2]);
			ea.prod_code = be16_to_cpup((__be16 *)&buf[4]);
			ea.dev_index = buf[6];
			ea.instance = buf[7];

			ret = slim_device_report_present(&ctrl->ctrl, &ea,
							 &laddr);
			if (ret < 0)
				dev_err(ctrl->dev, "assign laddr failed:%d\n",
					ret);
		} else {
			dev_err(ctrl->dev, "unexpected message:mc:%x, mt:%x\n",
				mc, mt);
		}
	}
}

static void qcom_slim_prg_slew(struct platform_device *pdev,
				struct qcom_slim_ctrl *ctrl)
{
	if (!ctrl->slew_reg) {
		/* SLEW RATE register for this SLIMbus */
		ctrl->slew_reg = devm_platform_ioremap_resource_byname(pdev, "slew");
		if (IS_ERR(ctrl->slew_reg))
			return;
	}

	writel_relaxed(1, ctrl->slew_reg);
	/* Make sure SLIMbus-slew rate enabling goes through */
	wmb();
}

static int qcom_slim_probe(struct platform_device *pdev)
{
	struct qcom_slim_ctrl *ctrl;
	struct slim_controller *sctrl;
	struct resource *slim_mem;
	int ret, ver;

	ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
	if (!ctrl)
		return -ENOMEM;

	ctrl->hclk = devm_clk_get(&pdev->dev, "iface");
	if (IS_ERR(ctrl->hclk))
		return PTR_ERR(ctrl->hclk);

	ctrl->rclk = devm_clk_get(&pdev->dev, "core");
	if (IS_ERR(ctrl->rclk))
		return PTR_ERR(ctrl->rclk);

	ret = clk_set_rate(ctrl->rclk, SLIM_ROOT_FREQ);
	if (ret) {
		dev_err(&pdev->dev, "ref-clock set-rate failed:%d\n", ret);
		return ret;
	}

	ctrl->irq = platform_get_irq(pdev, 0);
	if (!ctrl->irq) {
		dev_err(&pdev->dev, "no slimbus IRQ\n");
		return -ENODEV;
	}

	sctrl = &ctrl->ctrl;
	sctrl->dev = &pdev->dev;
	ctrl->dev = &pdev->dev;
	platform_set_drvdata(pdev, ctrl);
	dev_set_drvdata(ctrl->dev, ctrl);

	slim_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctrl");
	ctrl->base = devm_ioremap_resource(ctrl->dev, slim_mem);
	if (IS_ERR(ctrl->base))
		return PTR_ERR(ctrl->base);

	sctrl->set_laddr = qcom_set_laddr;
	sctrl->xfer_msg = qcom_xfer_msg;
	sctrl->wakeup =  qcom_clk_pause_wakeup;
	ctrl->tx.n = QCOM_TX_MSGS;
	ctrl->tx.sl_sz = SLIM_MSGQ_BUF_LEN;
	ctrl->rx.n = QCOM_RX_MSGS;
	ctrl->rx.sl_sz = SLIM_MSGQ_BUF_LEN;
	ctrl->wr_comp = kcalloc(QCOM_TX_MSGS, sizeof(struct completion *),
				GFP_KERNEL);
	if (!ctrl->wr_comp)
		return -ENOMEM;

	spin_lock_init(&ctrl->rx.lock);
	spin_lock_init(&ctrl->tx.lock);
	INIT_WORK(&ctrl->wd, qcom_slim_rxwq);
	ctrl->rxwq = create_singlethread_workqueue("qcom_slim_rx");
	if (!ctrl->rxwq) {
		dev_err(ctrl->dev, "Failed to start Rx WQ\n");
		return -ENOMEM;
	}

	ctrl->framer.rootfreq = SLIM_ROOT_FREQ / 8;
	ctrl->framer.superfreq =
		ctrl->framer.rootfreq / SLIM_CL_PER_SUPERFRAME_DIV8;
	sctrl->a_framer = &ctrl->framer;
	sctrl->clkgear = SLIM_MAX_CLK_GEAR;

	qcom_slim_prg_slew(pdev, ctrl);

	ret = devm_request_irq(&pdev->dev, ctrl->irq, qcom_slim_interrupt,
				IRQF_TRIGGER_HIGH, "qcom_slim_irq", ctrl);
	if (ret) {
		dev_err(&pdev->dev, "request IRQ failed\n");
		goto err_request_irq_failed;
	}

	ret = clk_prepare_enable(ctrl->hclk);
	if (ret)
		goto err_hclk_enable_failed;

	ret = clk_prepare_enable(ctrl->rclk);
	if (ret)
		goto err_rclk_enable_failed;

	ctrl->tx.base = devm_kcalloc(&pdev->dev, ctrl->tx.n, ctrl->tx.sl_sz,
				     GFP_KERNEL);
	if (!ctrl->tx.base) {
		ret = -ENOMEM;
		goto err;
	}

	ctrl->rx.base = devm_kcalloc(&pdev->dev,ctrl->rx.n, ctrl->rx.sl_sz,
				     GFP_KERNEL);
	if (!ctrl->rx.base) {
		ret = -ENOMEM;
		goto err;
	}

	/* Register with framework before enabling frame, clock */
	ret = slim_register_controller(&ctrl->ctrl);
	if (ret) {
		dev_err(ctrl->dev, "error adding controller\n");
		goto err;
	}

	ver = readl_relaxed(ctrl->base);
	/* Version info in 16 MSbits */
	ver >>= 16;
	/* Component register initialization */
	writel(1, ctrl->base + CFG_PORT(COMP_CFG, ver));
	writel((EE_MGR_RSC_GRP | EE_NGD_2 | EE_NGD_1),
				ctrl->base + CFG_PORT(COMP_TRUST_CFG, ver));

	writel((MGR_INT_TX_NACKED_2 |
			MGR_INT_MSG_BUF_CONTE | MGR_INT_RX_MSG_RCVD |
			MGR_INT_TX_MSG_SENT), ctrl->base + MGR_INT_EN);
	writel(1, ctrl->base + MGR_CFG);
	/* Framer register initialization */
	writel((1 << INTR_WAKE) | (0xA << REF_CLK_GEAR) |
		(0xA << CLK_GEAR) | (1 << ROOT_FREQ) | (1 << FRM_ACTIVE) | 1,
		ctrl->base + FRM_CFG);
	writel(MGR_CFG_ENABLE, ctrl->base + MGR_CFG);
	writel(1, ctrl->base + INTF_CFG);
	writel(1, ctrl->base + CFG_PORT(COMP_CFG, ver));

	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_set_autosuspend_delay(&pdev->dev, QCOM_SLIM_AUTOSUSPEND);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_mark_last_busy(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	dev_dbg(ctrl->dev, "QCOM SB controller is up:ver:0x%x!\n", ver);
	return 0;

err:
	clk_disable_unprepare(ctrl->rclk);
err_rclk_enable_failed:
	clk_disable_unprepare(ctrl->hclk);
err_hclk_enable_failed:
err_request_irq_failed:
	destroy_workqueue(ctrl->rxwq);
	return ret;
}

static int qcom_slim_remove(struct platform_device *pdev)
{
	struct qcom_slim_ctrl *ctrl = platform_get_drvdata(pdev);

	pm_runtime_disable(&pdev->dev);
	slim_unregister_controller(&ctrl->ctrl);
	clk_disable_unprepare(ctrl->rclk);
	clk_disable_unprepare(ctrl->hclk);
	destroy_workqueue(ctrl->rxwq);
	return 0;
}

/*
 * If PM_RUNTIME is not defined, these 2 functions become helper
 * functions to be called from system suspend/resume.
 */
#ifdef CONFIG_PM
static int qcom_slim_runtime_suspend(struct device *device)
{
	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(device);
	int ret;

	dev_dbg(device, "pm_runtime: suspending...\n");
	ret = slim_ctrl_clk_pause(&ctrl->ctrl, false, SLIM_CLK_UNSPECIFIED);
	if (ret) {
		dev_err(device, "clk pause not entered:%d", ret);
	} else {
		disable_irq(ctrl->irq);
		clk_disable_unprepare(ctrl->hclk);
		clk_disable_unprepare(ctrl->rclk);
	}
	return ret;
}

static int qcom_slim_runtime_resume(struct device *device)
{
	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(device);
	int ret = 0;

	dev_dbg(device, "pm_runtime: resuming...\n");
	ret = slim_ctrl_clk_pause(&ctrl->ctrl, true, 0);
	if (ret)
		dev_err(device, "clk pause not exited:%d", ret);
	return ret;
}
#endif

#ifdef CONFIG_PM_SLEEP
static int qcom_slim_suspend(struct device *dev)
{
	int ret = 0;

	if (!pm_runtime_enabled(dev) ||
		(!pm_runtime_suspended(dev))) {
		dev_dbg(dev, "system suspend");
		ret = qcom_slim_runtime_suspend(dev);
	}

	return ret;
}

static int qcom_slim_resume(struct device *dev)
{
	if (!pm_runtime_enabled(dev) || !pm_runtime_suspended(dev)) {
		int ret;

		dev_dbg(dev, "system resume");
		ret = qcom_slim_runtime_resume(dev);
		if (!ret) {
			pm_runtime_mark_last_busy(dev);
			pm_request_autosuspend(dev);
		}
		return ret;

	}
	return 0;
}
#endif /* CONFIG_PM_SLEEP */

static const struct dev_pm_ops qcom_slim_dev_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(qcom_slim_suspend, qcom_slim_resume)
	SET_RUNTIME_PM_OPS(
			   qcom_slim_runtime_suspend,
			   qcom_slim_runtime_resume,
			   NULL
	)
};

static const struct of_device_id qcom_slim_dt_match[] = {
	{ .compatible = "qcom,slim", },
	{ .compatible = "qcom,apq8064-slim", },
	{}
};

static struct platform_driver qcom_slim_driver = {
	.probe = qcom_slim_probe,
	.remove = qcom_slim_remove,
	.driver	= {
		.name = "qcom_slim_ctrl",
		.of_match_table = qcom_slim_dt_match,
		.pm = &qcom_slim_dev_pm_ops,
	},
};
module_platform_driver(qcom_slim_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Qualcomm SLIMbus Controller");