From 3b5db9d024f173c30ef4060c31bb8e9fbd194cc1 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Mon, 2 Dec 2013 16:13:32 +0100
Subject: [PATCH] libahci: Allow drivers to override start_engine

Allwinner A10 and A20 ARM SoCs have an AHCI sata controller which needs a
special register to be poked before starting the DMA engine.

This register gets reset on an ahci_stop_engine call, so there is no other
place then ahci_start_engine where this poking can be done.

This commit allows drivers to override ahci_start_engine behavior for use by
the Allwinner AHCI driver (and potentially other drivers in the future).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/ata/ahci.c          |  6 ++++--
 drivers/ata/ahci.h          |  6 ++++++
 drivers/ata/libahci.c       | 26 +++++++++++++++++++-------
 drivers/ata/sata_highbank.c |  3 ++-
 4 files changed, 31 insertions(+), 10 deletions(-)

--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -583,6 +583,7 @@ static int ahci_vt8251_hardreset(struct
 				 unsigned long deadline)
 {
 	struct ata_port *ap = link->ap;
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	bool online;
 	int rc;
 
@@ -593,7 +594,7 @@ static int ahci_vt8251_hardreset(struct
 	rc = sata_link_hardreset(link, sata_ehc_deb_timing(&link->eh_context),
 				 deadline, &online, NULL);
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 
 	DPRINTK("EXIT, rc=%d, class=%u\n", rc, *class);
 
@@ -608,6 +609,7 @@ static int ahci_p5wdh_hardreset(struct a
 {
 	struct ata_port *ap = link->ap;
 	struct ahci_port_priv *pp = ap->private_data;
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
 	struct ata_taskfile tf;
 	bool online;
@@ -623,7 +625,7 @@ static int ahci_p5wdh_hardreset(struct a
 	rc = sata_link_hardreset(link, sata_ehc_deb_timing(&link->eh_context),
 				 deadline, &online, NULL);
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 
 	/* The pseudo configuration device on SIMG4726 attached to
 	 * ASUS P5W-DH Deluxe doesn't send signature FIS after
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -37,6 +37,7 @@
 
 #include <linux/clk.h>
 #include <linux/libata.h>
+#include <linux/regulator/consumer.h>
 
 /* Enclosure Management Control */
 #define EM_CTRL_MSG_TYPE              0x000f0000
@@ -51,6 +52,7 @@
 
 enum {
 	AHCI_MAX_PORTS		= 32,
+	AHCI_MAX_CLKS		= 3,
 	AHCI_MAX_SG		= 168, /* hardware max is 64K */
 	AHCI_DMA_BOUNDARY	= 0xffffffff,
 	AHCI_MAX_CMDS		= 32,
@@ -322,8 +324,15 @@ struct ahci_host_priv {
 	u32 			em_loc; /* enclosure management location */
 	u32			em_buf_sz;	/* EM buffer size in byte */
 	u32			em_msg_type;	/* EM message type */
-	struct clk		*clk;		/* Only for platforms supporting clk */
+	struct clk		*clks[AHCI_MAX_CLKS]; /* Optional */
+	struct regulator	*target_pwr;	/* Optional */
 	void			*plat_data;	/* Other platform data */
+	/*
+	 * Optional ahci_start_engine override, if not set this gets set to the
+	 * default ahci_start_engine during ahci_save_initial_config, this can
+	 * be overridden anytime before the host is activated.
+	 */
+	void			(*start_engine)(struct ata_port *ap);
 };
 
 extern int ahci_ignore_sss;
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -394,6 +394,9 @@ static ssize_t ahci_show_em_supported(st
  *
  *	If inconsistent, config values are fixed up by this function.
  *
+ *	If it is not set already this function sets hpriv->start_engine to
+ *	ahci_start_engine.
+ *
  *	LOCKING:
  *	None.
  */
@@ -500,6 +503,9 @@ void ahci_save_initial_config(struct dev
 	hpriv->cap = cap;
 	hpriv->cap2 = cap2;
 	hpriv->port_map = port_map;
+
+	if (!hpriv->start_engine)
+		hpriv->start_engine = ahci_start_engine;
 }
 EXPORT_SYMBOL_GPL(ahci_save_initial_config);
 
@@ -766,7 +772,7 @@ static void ahci_start_port(struct ata_p
 
 	/* enable DMA */
 	if (!(hpriv->flags & AHCI_HFLAG_DELAY_ENGINE))
-		ahci_start_engine(ap);
+		hpriv->start_engine(ap);
 
 	/* turn on LEDs */
 	if (ap->flags & ATA_FLAG_EM) {
@@ -1234,7 +1240,7 @@ int ahci_kick_engine(struct ata_port *ap
 
 	/* restart engine */
  out_restart:
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(ahci_kick_engine);
@@ -1426,6 +1432,7 @@ static int ahci_hardreset(struct ata_lin
 	const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
 	struct ata_port *ap = link->ap;
 	struct ahci_port_priv *pp = ap->private_data;
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
 	struct ata_taskfile tf;
 	bool online;
@@ -1443,7 +1450,7 @@ static int ahci_hardreset(struct ata_lin
 	rc = sata_link_hardreset(link, timing, deadline, &online,
 				 ahci_check_ready);
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 
 	if (online)
 		*class = ahci_dev_classify(ap);
@@ -2007,10 +2014,12 @@ static void ahci_thaw(struct ata_port *a
 
 void ahci_error_handler(struct ata_port *ap)
 {
+	struct ahci_host_priv *hpriv = ap->host->private_data;
+
 	if (!(ap->pflags & ATA_PFLAG_FROZEN)) {
 		/* restart engine */
 		ahci_stop_engine(ap);
-		ahci_start_engine(ap);
+		hpriv->start_engine(ap);
 	}
 
 	sata_pmp_error_handler(ap);
@@ -2031,6 +2040,7 @@ static void ahci_post_internal_cmd(struc
 
 static void ahci_set_aggressive_devslp(struct ata_port *ap, bool sleep)
 {
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	void __iomem *port_mmio = ahci_port_base(ap);
 	struct ata_device *dev = ap->link.device;
 	u32 devslp, dm, dito, mdat, deto;
@@ -2094,7 +2104,7 @@ static void ahci_set_aggressive_devslp(s
 		   PORT_DEVSLP_ADSE);
 	writel(devslp, port_mmio + PORT_DEVSLP);
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 
 	/* enable device sleep feature for the drive */
 	err_mask = ata_dev_set_feature(dev,
@@ -2106,6 +2116,7 @@ static void ahci_set_aggressive_devslp(s
 
 static void ahci_enable_fbs(struct ata_port *ap)
 {
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	struct ahci_port_priv *pp = ap->private_data;
 	void __iomem *port_mmio = ahci_port_base(ap);
 	u32 fbs;
@@ -2134,11 +2145,12 @@ static void ahci_enable_fbs(struct ata_p
 	} else
 		dev_err(ap->host->dev, "Failed to enable FBS\n");
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 }
 
 static void ahci_disable_fbs(struct ata_port *ap)
 {
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	struct ahci_port_priv *pp = ap->private_data;
 	void __iomem *port_mmio = ahci_port_base(ap);
 	u32 fbs;
@@ -2166,7 +2178,7 @@ static void ahci_disable_fbs(struct ata_
 		pp->fbs_enabled = false;
 	}
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 }
 
 static void ahci_pmp_attach(struct ata_port *ap)
--- a/drivers/ata/sata_highbank.c
+++ b/drivers/ata/sata_highbank.c
@@ -403,6 +403,7 @@ static int ahci_highbank_hardreset(struc
 	static const unsigned long timing[] = { 5, 100, 500};
 	struct ata_port *ap = link->ap;
 	struct ahci_port_priv *pp = ap->private_data;
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
 	struct ata_taskfile tf;
 	bool online;
@@ -431,7 +432,7 @@ static int ahci_highbank_hardreset(struc
 			break;
 	} while (!online && retry--);
 
-	ahci_start_engine(ap);
+	hpriv->start_engine(ap);
 
 	if (online)
 		*class = ahci_dev_classify(ap);
--- a/Documentation/devicetree/bindings/ata/ahci-platform.txt
+++ b/Documentation/devicetree/bindings/ata/ahci-platform.txt
@@ -10,6 +10,8 @@ Required properties:
 
 Optional properties:
 - dma-coherent      : Present if dma operations are coherent
+- clocks            : a list of phandle + clock specifier pairs
+- target-supply     : regulator for SATA target power
 
 Example:
         sata@ffe08000 {
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -87,78 +87,252 @@ static struct scsi_host_template ahci_pl
 	AHCI_SHT("ahci_platform"),
 };
 
-static int ahci_probe(struct platform_device *pdev)
+/**
+ *	ahci_platform_enable_clks - Enable platform clocks
+ *	@hpriv: host private area to store config values
+ *
+ *	This function enables all the clks found in hpriv->clks, starting
+ *	at index 0. If any clk fails to enable it disables all the clks
+ *	already enabled in reverse order, and then returns an error.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_enable_clks(struct ahci_host_priv *hpriv)
 {
-	struct device *dev = &pdev->dev;
-	struct ahci_platform_data *pdata = dev_get_platdata(dev);
-	const struct platform_device_id *id = platform_get_device_id(pdev);
-	struct ata_port_info pi = ahci_port_info[id ? id->driver_data : 0];
-	const struct ata_port_info *ppi[] = { &pi, NULL };
-	struct ahci_host_priv *hpriv;
-	struct ata_host *host;
-	struct resource *mem;
-	int irq;
-	int n_ports;
-	int i;
-	int rc;
+	int c, rc;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!mem) {
-		dev_err(dev, "no mmio space\n");
-		return -EINVAL;
+	for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++) {
+		rc = clk_prepare_enable(hpriv->clks[c]);
+		if (rc)
+			goto disable_unprepare_clk;
 	}
+	return 0;
 
-	irq = platform_get_irq(pdev, 0);
-	if (irq <= 0) {
-		dev_err(dev, "no irq\n");
-		return -EINVAL;
-	}
+disable_unprepare_clk:
+	while (--c >= 0)
+		clk_disable_unprepare(hpriv->clks[c]);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ahci_platform_enable_clks);
 
-	if (pdata && pdata->ata_port_info)
-		pi = *pdata->ata_port_info;
+/**
+ *	ahci_platform_disable_clks - Disable platform clocks
+ *	@hpriv: host private area to store config values
+ *
+ *	This function disables all the clks found in hpriv->clks, in reverse
+ *	order of ahci_platform_enable_clks (starting at the end of the array).
+ *
+ *	LOCKING:
+ *	None.
+ */
+void ahci_platform_disable_clks(struct ahci_host_priv *hpriv)
+{
+	int c;
 
-	hpriv = devm_kzalloc(dev, sizeof(*hpriv), GFP_KERNEL);
-	if (!hpriv) {
-		dev_err(dev, "can't alloc ahci_host_priv\n");
-		return -ENOMEM;
+	for (c = AHCI_MAX_CLKS - 1; c >= 0; c--)
+		if (hpriv->clks[c])
+			clk_disable_unprepare(hpriv->clks[c]);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_disable_clks);
+
+/**
+ *	ahci_platform_enable_resources - Enable platform resources
+ *	@hpriv: host private area to store config values
+ *
+ *	This function enables all ahci_platform managed resources in
+ *	the following order:
+ *	1) Regulator
+ *	2) Clocks (through ahci_platform_enable_clks)
+ *
+ *	If resource enabling fails at any point the previous enabled
+ *	resources are disabled in reverse order.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_enable_resources(struct ahci_host_priv *hpriv)
+{
+	int rc;
+
+	if (hpriv->target_pwr) {
+		rc = regulator_enable(hpriv->target_pwr);
+		if (rc)
+			return rc;
 	}
 
-	hpriv->flags |= (unsigned long)pi.private_data;
+	rc = ahci_platform_enable_clks(hpriv);
+	if (rc)
+		goto disable_regulator;
+
+	return 0;
+
+disable_regulator:
+	if (hpriv->target_pwr)
+		regulator_disable(hpriv->target_pwr);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ahci_platform_enable_resources);
+
+/**
+ *	ahci_platform_disable_resources - Disable platform resources
+ *	@hpriv: host private area to store config values
+ *
+ *	This function disables all ahci_platform managed resources in
+ *	the following order:
+ *	1) Clocks (through ahci_platform_disable_clks)
+ *	2) Regulator
+ *
+ *	LOCKING:
+ *	None.
+ */
+void ahci_platform_disable_resources(struct ahci_host_priv *hpriv)
+{
+	ahci_platform_disable_clks(hpriv);
 
-	hpriv->mmio = devm_ioremap(dev, mem->start, resource_size(mem));
+	if (hpriv->target_pwr)
+		regulator_disable(hpriv->target_pwr);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_disable_resources);
+
+static void ahci_platform_put_resources(struct device *dev, void *res)
+{
+	struct ahci_host_priv *hpriv = res;
+	int c;
+
+	for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++)
+		clk_put(hpriv->clks[c]);
+}
+
+/**
+ *	ahci_platform_get_resources - Get platform resources
+ *	@pdev: platform device to get resources for
+ *
+ *	This function allocates an ahci_host_priv struct, and gets the
+ *	following resources, storing a reference to them inside the returned
+ *	struct:
+ *
+ *	1) mmio registers (IORESOURCE_MEM 0, mandatory)
+ *	2) regulator for controlling the targets power (optional)
+ *	3) 0 - AHCI_MAX_CLKS clocks, as specified in the devs devicetree node,
+ *	   or for non devicetree enabled platforms a single clock
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	The allocated ahci_host_priv on success, otherwise an ERR_PTR value
+ */
+struct ahci_host_priv *ahci_platform_get_resources(
+	struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ahci_host_priv *hpriv;
+	struct clk *clk;
+	int i, rc = -ENOMEM;
+
+	if (!devres_open_group(dev, NULL, GFP_KERNEL))
+		return ERR_PTR(-ENOMEM);
+
+	hpriv = devres_alloc(ahci_platform_put_resources, sizeof(*hpriv),
+			     GFP_KERNEL);
+	if (!hpriv)
+		goto err_out;
+
+	devres_add(dev, hpriv);
+
+	hpriv->mmio = devm_ioremap_resource(dev,
+			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
 	if (!hpriv->mmio) {
-		dev_err(dev, "can't map %pR\n", mem);
-		return -ENOMEM;
+		dev_err(dev, "no mmio space\n");
+		goto err_out;
 	}
 
-	hpriv->clk = clk_get(dev, NULL);
-	if (IS_ERR(hpriv->clk)) {
-		dev_err(dev, "can't get clock\n");
-	} else {
-		rc = clk_prepare_enable(hpriv->clk);
-		if (rc) {
-			dev_err(dev, "clock prepare enable failed");
-			goto free_clk;
+	hpriv->target_pwr = devm_regulator_get_optional(dev, "target");
+	if (IS_ERR(hpriv->target_pwr)) {
+		rc = PTR_ERR(hpriv->target_pwr);
+		if (rc == -EPROBE_DEFER)
+			goto err_out;
+		hpriv->target_pwr = NULL;
+	}
+
+	for (i = 0; i < AHCI_MAX_CLKS; i++) {
+		/*
+		 * For now we must use clk_get(dev, NULL) for the first clock,
+		 * because some platforms (da850, spear13xx) are not yet
+		 * converted to use devicetree for clocks.  For new platforms
+		 * this is equivalent to of_clk_get(dev->of_node, 0).
+		 */
+		if (i == 0)
+			clk = clk_get(dev, NULL);
+		else
+			clk = of_clk_get(dev->of_node, i);
+
+		if (IS_ERR(clk)) {
+			rc = PTR_ERR(clk);
+			if (rc == -EPROBE_DEFER)
+				goto err_out;
+			break;
 		}
+		hpriv->clks[i] = clk;
 	}
 
-	/*
-	 * Some platforms might need to prepare for mmio region access,
-	 * which could be done in the following init call. So, the mmio
-	 * region shouldn't be accessed before init (if provided) has
-	 * returned successfully.
-	 */
-	if (pdata && pdata->init) {
-		rc = pdata->init(dev, hpriv->mmio);
-		if (rc)
-			goto disable_unprepare_clk;
-	}
+	devres_remove_group(dev, NULL);
+	return hpriv;
+
+err_out:
+	devres_release_group(dev, NULL);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_get_resources);
+
+/**
+ *	ahci_platform_init_host - Bring up an ahci-platform host
+ *	@pdev: platform device pointer for the host
+ *	@hpriv: ahci-host private data for the host
+ *	@pi_template: template for the ata_port_info to use
+ *	@force_port_map: param passed to ahci_save_initial_config
+ *	@mask_port_map: param passed to ahci_save_initial_config
+ *
+ *	This function does all the usual steps needed to bring up an
+ *	ahci-platform host, note any necessary resources (ie clks, phy, etc.)
+ *	must be initialized / enabled before calling this.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_init_host(struct platform_device *pdev,
+			    struct ahci_host_priv *hpriv,
+			    const struct ata_port_info *pi_template,
+			    unsigned int force_port_map,
+			    unsigned int mask_port_map)
+{
+	struct device *dev = &pdev->dev;
+	struct ata_port_info pi = *pi_template;
+	const struct ata_port_info *ppi[] = { &pi, NULL };
+	struct ata_host *host;
+	int i, irq, n_ports, rc;
 
-	ahci_save_initial_config(dev, hpriv,
-		pdata ? pdata->force_port_map : 0,
-		pdata ? pdata->mask_port_map  : 0);
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0) {
+		dev_err(dev, "no irq\n");
+		return -EINVAL;
+	}
 
 	/* prepare host */
+	hpriv->flags |= (unsigned long)pi.private_data;
+
+	ahci_save_initial_config(dev, hpriv, force_port_map, mask_port_map);
+
 	if (hpriv->cap & HOST_CAP_NCQ)
 		pi.flags |= ATA_FLAG_NCQ;
 
@@ -175,10 +349,8 @@ static int ahci_probe(struct platform_de
 	n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
 
 	host = ata_host_alloc_pinfo(dev, ppi, n_ports);
-	if (!host) {
-		rc = -ENOMEM;
-		goto pdata_exit;
-	}
+	if (!host)
+		return -ENOMEM;
 
 	host->private_data = hpriv;
 
@@ -193,7 +365,8 @@ static int ahci_probe(struct platform_de
 	for (i = 0; i < host->n_ports; i++) {
 		struct ata_port *ap = host->ports[i];
 
-		ata_port_desc(ap, "mmio %pR", mem);
+		ata_port_desc(ap, "mmio %pR",
+			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
 		ata_port_desc(ap, "port 0x%x", 0x100 + ap->port_no * 0x80);
 
 		/* set enclosure management message type */
@@ -207,13 +380,53 @@ static int ahci_probe(struct platform_de
 
 	rc = ahci_reset_controller(host);
 	if (rc)
-		goto pdata_exit;
+		return rc;
 
 	ahci_init_controller(host);
 	ahci_print_info(host, "platform");
 
-	rc = ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
-			       &ahci_platform_sht);
+	return ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
+				 &ahci_platform_sht);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_init_host);
+
+static int ahci_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ahci_platform_data *pdata = dev_get_platdata(dev);
+	const struct platform_device_id *id = platform_get_device_id(pdev);
+	const struct ata_port_info *pi_template;
+	struct ahci_host_priv *hpriv;
+	int rc;
+
+	hpriv = ahci_platform_get_resources(pdev);
+	if (IS_ERR(hpriv))
+		return PTR_ERR(hpriv);
+
+	rc = ahci_platform_enable_resources(hpriv);
+	if (rc)
+		return rc;
+
+	/*
+	 * Some platforms might need to prepare for mmio region access,
+	 * which could be done in the following init call. So, the mmio
+	 * region shouldn't be accessed before init (if provided) has
+	 * returned successfully.
+	 */
+	if (pdata && pdata->init) {
+		rc = pdata->init(dev, hpriv->mmio);
+		if (rc)
+			goto disable_resources;
+	}
+
+	if (pdata && pdata->ata_port_info)
+		pi_template = pdata->ata_port_info;
+	else
+		pi_template = &ahci_port_info[id ? id->driver_data : 0];
+
+	rc = ahci_platform_init_host(pdev, hpriv, pi_template,
+				     pdata ? pdata->force_port_map : 0,
+				     pdata ? pdata->mask_port_map  : 0);
 	if (rc)
 		goto pdata_exit;
 
@@ -221,12 +434,8 @@ static int ahci_probe(struct platform_de
 pdata_exit:
 	if (pdata && pdata->exit)
 		pdata->exit(dev);
-disable_unprepare_clk:
-	if (!IS_ERR(hpriv->clk))
-		clk_disable_unprepare(hpriv->clk);
-free_clk:
-	if (!IS_ERR(hpriv->clk))
-		clk_put(hpriv->clk);
+disable_resources:
+	ahci_platform_disable_resources(hpriv);
 	return rc;
 }
 
@@ -239,21 +448,30 @@ static void ahci_host_stop(struct ata_ho
 	if (pdata && pdata->exit)
 		pdata->exit(dev);
 
-	if (!IS_ERR(hpriv->clk)) {
-		clk_disable_unprepare(hpriv->clk);
-		clk_put(hpriv->clk);
-	}
+	ahci_platform_disable_resources(hpriv);
 }
 
 #ifdef CONFIG_PM_SLEEP
-static int ahci_suspend(struct device *dev)
+/**
+ *	ahci_platform_suspend_host - Suspend an ahci-platform host
+ *	@dev: device pointer for the host
+ *
+ *	This function does all the usual steps needed to suspend an
+ *	ahci-platform host, note any necessary resources (ie clks, phy, etc.)
+ *	must be disabled after calling this.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_suspend_host(struct device *dev)
 {
-	struct ahci_platform_data *pdata = dev_get_platdata(dev);
 	struct ata_host *host = dev_get_drvdata(dev);
 	struct ahci_host_priv *hpriv = host->private_data;
 	void __iomem *mmio = hpriv->mmio;
 	u32 ctl;
-	int rc;
 
 	if (hpriv->flags & AHCI_HFLAG_NO_SUSPEND) {
 		dev_err(dev, "firmware update required for suspend/resume\n");
@@ -270,61 +488,122 @@ static int ahci_suspend(struct device *d
 	writel(ctl, mmio + HOST_CTL);
 	readl(mmio + HOST_CTL); /* flush */
 
-	rc = ata_host_suspend(host, PMSG_SUSPEND);
+	return ata_host_suspend(host, PMSG_SUSPEND);
+}
+EXPORT_SYMBOL_GPL(ahci_platform_suspend_host);
+
+/**
+ *	ahci_platform_resume_host - Resume an ahci-platform host
+ *	@dev: device pointer for the host
+ *
+ *	This function does all the usual steps needed to resume an
+ *	ahci-platform host, note any necessary resources (ie clks, phy, etc.)
+ *	must be initialized / enabled before calling this.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_resume_host(struct device *dev)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	int rc;
+
+	if (dev->power.power_state.event == PM_EVENT_SUSPEND) {
+		rc = ahci_reset_controller(host);
+		if (rc)
+			return rc;
+
+		ahci_init_controller(host);
+	}
+
+	ata_host_resume(host);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ahci_platform_resume_host);
+
+/**
+ *	ahci_platform_suspend - Suspend an ahci-platform device
+ *	@dev: the platform device to suspend
+ *
+ *	This function suspends the host associated with the device, followed
+ *	by disabling all the resources of the device.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_suspend(struct device *dev)
+{
+	struct ahci_platform_data *pdata = dev_get_platdata(dev);
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct ahci_host_priv *hpriv = host->private_data;
+	int rc;
+
+	rc = ahci_platform_suspend_host(dev);
 	if (rc)
 		return rc;
 
 	if (pdata && pdata->suspend)
 		return pdata->suspend(dev);
 
-	if (!IS_ERR(hpriv->clk))
-		clk_disable_unprepare(hpriv->clk);
+	ahci_platform_disable_resources(hpriv);
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(ahci_platform_suspend);
 
-static int ahci_resume(struct device *dev)
+/**
+ *	ahci_platform_resume - Resume an ahci-platform device
+ *	@dev: the platform device to resume
+ *
+ *	This function enables all the resources of the device followed by
+ *	resuming the host associated with the device.
+ *
+ *	LOCKING:
+ *	None.
+ *
+ *	RETURNS:
+ *	0 on success otherwise a negative error code
+ */
+int ahci_platform_resume(struct device *dev)
 {
 	struct ahci_platform_data *pdata = dev_get_platdata(dev);
 	struct ata_host *host = dev_get_drvdata(dev);
 	struct ahci_host_priv *hpriv = host->private_data;
 	int rc;
 
-	if (!IS_ERR(hpriv->clk)) {
-		rc = clk_prepare_enable(hpriv->clk);
-		if (rc) {
-			dev_err(dev, "clock prepare enable failed");
-			return rc;
-		}
-	}
+	rc = ahci_platform_enable_resources(hpriv);
+	if (rc)
+		return rc;
 
 	if (pdata && pdata->resume) {
 		rc = pdata->resume(dev);
 		if (rc)
-			goto disable_unprepare_clk;
-	}
-
-	if (dev->power.power_state.event == PM_EVENT_SUSPEND) {
-		rc = ahci_reset_controller(host);
-		if (rc)
-			goto disable_unprepare_clk;
-
-		ahci_init_controller(host);
+			goto disable_resources;
 	}
 
-	ata_host_resume(host);
+	rc = ahci_platform_resume_host(dev);
+	if (rc)
+		goto disable_resources;
 
 	return 0;
 
-disable_unprepare_clk:
-	if (!IS_ERR(hpriv->clk))
-		clk_disable_unprepare(hpriv->clk);
+disable_resources:
+	ahci_platform_disable_resources(hpriv);
 
 	return rc;
 }
+EXPORT_SYMBOL_GPL(ahci_platform_resume);
 #endif
 
-static SIMPLE_DEV_PM_OPS(ahci_pm_ops, ahci_suspend, ahci_resume);
+static SIMPLE_DEV_PM_OPS(ahci_pm_ops, ahci_platform_suspend,
+			 ahci_platform_resume);
 
 static const struct of_device_id ahci_of_match[] = {
 	{ .compatible = "snps,spear-ahci", },
--- a/include/linux/ahci_platform.h
+++ b/include/linux/ahci_platform.h
@@ -19,7 +19,15 @@
 
 struct device;
 struct ata_port_info;
+struct ahci_host_priv;
+struct platform_device;
 
+/*
+ * Note ahci_platform_data is deprecated, it is only kept around for use
+ * by the old da850 and spear13xx ahci code.
+ * New drivers should instead declare their own platform_driver struct, and
+ * use ahci_platform* functions in their own probe, suspend and resume methods.
+ */
 struct ahci_platform_data {
 	int (*init)(struct device *dev, void __iomem *addr);
 	void (*exit)(struct device *dev);
@@ -30,4 +38,21 @@ struct ahci_platform_data {
 	unsigned int mask_port_map;
 };
 
+int ahci_platform_enable_clks(struct ahci_host_priv *hpriv);
+void ahci_platform_disable_clks(struct ahci_host_priv *hpriv);
+int ahci_platform_enable_resources(struct ahci_host_priv *hpriv);
+void ahci_platform_disable_resources(struct ahci_host_priv *hpriv);
+struct ahci_host_priv *ahci_platform_get_resources(
+	struct platform_device *pdev);
+int ahci_platform_init_host(struct platform_device *pdev,
+			    struct ahci_host_priv *hpriv,
+			    const struct ata_port_info *pi_template,
+			    unsigned int force_port_map,
+			    unsigned int mask_port_map);
+
+int ahci_platform_suspend_host(struct device *dev);
+int ahci_platform_resume_host(struct device *dev);
+int ahci_platform_suspend(struct device *dev);
+int ahci_platform_resume(struct device *dev);
+
 #endif /* _AHCI_PLATFORM_H */
