OMAP4: HSI: Add dynamic OPP change

Added an IOCTL to change HSI FClk to 96MHz or 192MHz.
Decision of when to increase/decrease modem speed is up to Link Layer.

Constraint :
* RX/TX divisors and RX error counters need to be changed after Fclk is changed.
* Read/Write operation must not be pending when OPP change request is issued, otherwise
OPP change is aborted.
* Any Read/Write operation started during HSI OPP change operation will be aborted.

Change-Id: I06e15a205e614506994989ec6a40c0383e32776d
Signed-off-by: Djamil Elaidi <d-elaidi@ti.com>

9 files changed, 128 insertions, 32 deletions

diff --git a/arch/arm/plat-omap/include/plat/omap_hsi.h b/arch/arm/plat-omap/include/plat/omap_hsi.h
index c64694e..d29062d 100644
--- a/arch/arm/plat-omap/include/plat/omap_hsi.h
+++ b/arch/arm/plat-omap/include/plat/omap_hsi.h
@@ -28,9 +28,13 @@
 #ifndef __OMAP_HSI_H__
 #define __OMAP_HSI_H__
 
+#define HSI_FCLK_LOW_SPEED		96000000	/* 96 MHz */
+#define HSI_FCLK_HI_SPEED		192000000	/* 192 MHz */
+#define HSI_FCLK_DPLL_CASCADING		98300000        /* 98.3 MHz */
+
 /* Set the HSI Functional Clock to 96MHz.
- * This is to ensure HSI will function even at OPP50. */
-#define HSI_DEFAULT_FCLK		96000000	/* 96 MHz */
+ * Warning : 192MHz will force OPP100 on VDD_CORE (no OPP50 possible) */
+#define HSI_DEFAULT_FCLK		HSI_FCLK_LOW_SPEED	/* 96 MHz */
 
 
 #define HSI_PORT_OFFSET			0x1000
diff --git a/drivers/omap_hsi/hsi-char.c b/drivers/omap_hsi/hsi-char.c
index 59193f4..8c0f406 100644
--- a/drivers/omap_hsi/hsi-char.c
+++ b/drivers/omap_hsi/hsi-char.c
@@ -361,6 +361,7 @@ static long  hsi_char_ioctl(struct file *file,
 	int ch = (int)file->private_data;
 	unsigned int state;
 	size_t size;
+	unsigned long fclock;
 	struct hsi_rx_config rx_cfg;
 	struct hsi_tx_config tx_cfg;
 	int ret = 0;
@@ -433,6 +434,17 @@ static long  hsi_char_ioctl(struct file *file,
 		if (copy_to_user((void __user *)arg, &size, sizeof(size)))
 			ret = -EFAULT;
 		break;
+	case CS_SET_HI_SPEED:
+		if (copy_from_user(&state, (void __user *)arg, sizeof(state)))
+			ret = -EFAULT;
+		else
+			if_hsi_set_hi_speed(ch, state);
+		break;
+	case CS_GET_SPEED:
+		if_hsi_get_speed(ch, &fclock);
+		if (copy_to_user((void __user *)arg, &fclock, sizeof(fclock)))
+			ret = -EFAULT;
+		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
diff --git a/drivers/omap_hsi/hsi-if.c b/drivers/omap_hsi/hsi-if.c
index bb3e03d..8f6002f 100644
--- a/drivers/omap_hsi/hsi-if.c
+++ b/drivers/omap_hsi/hsi-if.c
@@ -335,6 +335,23 @@ void if_hsi_sw_reset(int ch)
 	spin_unlock_bh(&hsi_iface.lock);
 }
 
+void if_hsi_set_hi_speed(int ch, unsigned int state)
+{
+	struct if_hsi_channel *channel;
+	channel = &hsi_iface.channels[ch];
+
+	spin_lock_bh(&hsi_iface.lock);
+	hsi_ioctl(channel->dev, HSI_IOCTL_SET_HI_SPEED, &state);
+	spin_unlock_bh(&hsi_iface.lock);
+}
+
+void if_hsi_get_speed(int ch, unsigned long *fclock)
+{
+	struct if_hsi_channel *channel;
+	channel = &hsi_iface.channels[ch];
+	hsi_ioctl(channel->dev, HSI_IOCTL_GET_SPEED, fclock);
+}
+
 void if_hsi_get_fifo_occupancy(int ch, size_t *occ)
 {
 	struct if_hsi_channel *channel;
diff --git a/drivers/omap_hsi/hsi-if.h b/drivers/omap_hsi/hsi-if.h
index f4bbf76..9cb120e 100644
--- a/drivers/omap_hsi/hsi-if.h
+++ b/drivers/omap_hsi/hsi-if.h
@@ -53,6 +53,8 @@ void if_hsi_set_acwakeline(int ch, unsigned int state);
 void if_hsi_get_acwakeline(int ch, unsigned int *state);
 void if_hsi_get_cawakeline(int ch, unsigned int *state);
 void if_hsi_set_wake_rx_3wires_mode(int ch, unsigned int state);
+void if_hsi_set_hi_speed(int ch, unsigned int state);
+void if_hsi_get_speed(int ch, unsigned long *fclock);
 int if_hsi_set_rx(int ch, struct hsi_rx_config *cfg);
 void if_hsi_get_rx(int ch, struct hsi_rx_config *cfg);
 int if_hsi_set_tx(int ch, struct hsi_tx_config *cfg);
diff --git a/drivers/omap_hsi/hsi_driver.c b/drivers/omap_hsi/hsi_driver.c
index 9efc2e3..a2ed3c2 100755
--- a/drivers/omap_hsi/hsi_driver.c
+++ b/drivers/omap_hsi/hsi_driver.c
@@ -174,7 +174,6 @@ int hsi_port_event_handler(struct hsi_port *p, unsigned int event, void *arg)
 	struct hsi_channel *hsi_channel;
 	int ch;
 
-
 	if (event == HSI_EVENT_HSR_DATAAVAILABLE) {
 		/* The data-available event is channel-specific and must not be
 		 * broadcasted
@@ -785,7 +784,8 @@ static int __init hsi_controller_init(struct hsi_dev *hsi_ctrl,
 	}
 	hsi_ctrl->max_p = pdata->num_ports;
 	hsi_ctrl->clock_enabled = false;
-	hsi_ctrl->clock_rate = 0;
+	hsi_ctrl->clock_change_ongoing = false;
+	hsi_ctrl->hsi_fclk_current = 0;
 	hsi_ctrl->in_dma_tasklet = false;
 	hsi_ctrl->fifo_mapping_strategy = pdata->fifo_mapping_strategy;
 	hsi_ctrl->dev = &pd->dev;
@@ -835,6 +835,12 @@ static int __init hsi_platform_device_probe(struct platform_device *pd)
 		return -ENXIO;
 	}
 
+	/* Check if mandatory board functions are populated */
+	if (!pdata->device_scale) {
+		dev_err(&pd->dev, "Missing platform device_scale function\n");
+		return -ENOSYS;
+	}
+
 	hsi_ctrl = kzalloc(sizeof(*hsi_ctrl), GFP_KERNEL);
 	if (hsi_ctrl == NULL) {
 		dev_err(&pd->dev, "Could not allocate memory for"
@@ -891,26 +897,21 @@ static int __init hsi_platform_device_probe(struct platform_device *pd)
 	device_init_wakeup(hsi_ctrl->dev, true);
 
 	/* Set the HSI FCLK to default. */
-	if (!pdata->device_scale) {
-		dev_err(&pd->dev, "%s: No platform device_scale function\n",
-			__func__);
-		err = -ENXIO;
-		goto rollback3;
-	}
+	hsi_ctrl->hsi_fclk_req = pdata->default_hsi_fclk;
 	err = pdata->device_scale(hsi_ctrl->dev, hsi_ctrl->dev,
 				  pdata->default_hsi_fclk);
 	if (err == -EBUSY) {
+		/* PM framework init is late_initcall, so it may not yet be */
+		/* initialized, so be prepared to retry later on open. */
 		dev_warn(&pd->dev, "Cannot set HSI FClk to default value: %ld. "
-			"Will retry on next open\n",
-			pdata->default_hsi_fclk);
+			 "Will retry on next open\n", pdata->default_hsi_fclk);
 	} else if (err) {
 		dev_err(&pd->dev, "%s: Error %d setting HSI FClk to %ld.\n",
 				__func__, err, pdata->default_hsi_fclk);
 		goto rollback3;
 	} else {
-		hsi_ctrl->clock_rate = pdata->default_hsi_fclk;
+		hsi_ctrl->hsi_fclk_current = pdata->default_hsi_fclk;
 	}
-
 	/* From here no need for HSI HW access */
 	hsi_clocks_disable(hsi_ctrl->dev, __func__);
 
diff --git a/drivers/omap_hsi/hsi_driver.h b/drivers/omap_hsi/hsi_driver.h
index 7ad5655..226fe15 100755
--- a/drivers/omap_hsi/hsi_driver.h
+++ b/drivers/omap_hsi/hsi_driver.h
@@ -174,7 +174,9 @@ struct hsi_port {
  * @phy_base: HSI registers base physical address
  * @lock: Serializes access to internal data and regs
  * @clock_enabled: Indicates if HSI Clocks are ON
- * @clock_rate: Indicates current HSI Fclock speed
+ * @clock_change_ongoing: Indicates if HSI FClk is being changed (OPP change)
+ * @hsi_fclk_req: Indicates what HSI FClk user requested (96MHz/192MHz)
+ * @hsi_fclk_current: Current HSI Fclock
  * @gdd_irq: GDD (DMA) irq number
  * @fifo_mapping_strategy: Selected strategy for fifo to ports/channels mapping
  * @gdd_usecount: Holds the number of ongoning DMA transfers
@@ -182,8 +184,6 @@ struct hsi_port {
  * @gdd_chan_count: Number of available DMA channels on the device (must be ^2)
  * @in_dma_tasklet: True if DMA tasklet for the controller is currently running
  * @set_min_bus_tput: (PM) callback to set minimun bus throuput
- * @clk_notifier_register: (PM) callabck for DVFS support
- * @clk_notifier_unregister: (PM) callabck for DVFS support
  * @hsi_nb: (PM) Notification block for DVFS notification chain
  * @hsi_gdd_tasklet: Bottom half for DMA Interrupts when clocks are enabled
  * @dir: debugfs base directory
@@ -197,7 +197,9 @@ struct hsi_dev { /* HSI_TODO:  should be later renamed into hsi_controller*/
 	unsigned long phy_base;
 	spinlock_t lock; /* Serializes access to internal data and regs */
 	bool clock_enabled;
-	unsigned long clock_rate;
+	bool clock_change_ongoing;
+	unsigned long hsi_fclk_req;
+	unsigned long hsi_fclk_current;
 	int gdd_irq;
 	unsigned int fifo_mapping_strategy;
 	unsigned int gdd_usecount;
diff --git a/drivers/omap_hsi/hsi_driver_if.c b/drivers/omap_hsi/hsi_driver_if.c
index 82b7239..f7ab392 100755
--- a/drivers/omap_hsi/hsi_driver_if.c
+++ b/drivers/omap_hsi/hsi_driver_if.c
@@ -289,22 +289,10 @@ int hsi_open(struct hsi_device *dev)
 		return -EINVAL;
 	}
 
-	if (hsi_ctrl->clock_rate == 0) {
+	if (hsi_ctrl->hsi_fclk_current == 0) {
 		struct hsi_platform_data *pdata;
 
 		pdata = dev_get_platdata(hsi_ctrl->dev);
-		if (!pdata) {
-			dev_err(dev->device.parent,
-				"%s: Port %d Channel %d has no pdata\n",
-				__func__, dev->n_p, dev->n_ch);
-			return -EINVAL;
-		}
-		if (!pdata->device_scale) {
-			dev_err(dev->device.parent,
-			       "%s: Undefined platform device_scale function\n",
-			       __func__);
-			return -ENXIO;
-		}
 
 		/* Retry to set the HSI FCLK to default. */
 		err = pdata->device_scale(hsi_ctrl->dev, hsi_ctrl->dev,
@@ -318,7 +306,7 @@ int hsi_open(struct hsi_device *dev)
 		} else {
 			dev_info(dev->device.parent, "HSI clock is now %ld\n",
 				 pdata->default_hsi_fclk);
-			hsi_ctrl->clock_rate = pdata->default_hsi_fclk;
+			hsi_ctrl->hsi_fclk_current = pdata->default_hsi_fclk;
 		}
 	}
 	spin_lock_bh(&hsi_ctrl->lock);
@@ -397,6 +385,11 @@ int hsi_write(struct hsi_device *dev, u32 *addr, unsigned int size)
 
 	spin_lock_bh(&hsi_ctrl->lock);
 
+	if (hsi_ctrl->clock_change_ongoing) {
+		dev_warn(hsi_ctrl->dev, "HSI Fclock change ongoing, retry.\n");
+		spin_unlock_bh(&hsi_ctrl->lock);
+		return -EAGAIN;
+	}
 
 	if (pm_runtime_suspended(hsi_ctrl->dev) || !hsi_ctrl->clock_enabled)
 		dev_dbg(hsi_ctrl->dev,
@@ -466,6 +459,13 @@ int hsi_read(struct hsi_device *dev, u32 *addr, unsigned int size)
 	hsi_ctrl = ch->hsi_port->hsi_controller;
 
 	spin_lock_bh(&hsi_ctrl->lock);
+
+	if (hsi_ctrl->clock_change_ongoing) {
+		dev_warn(hsi_ctrl->dev, "HSI Fclock change ongoing, retry.\n");
+		spin_unlock_bh(&hsi_ctrl->lock);
+		return -EAGAIN;
+	}
+
 	if (pm_runtime_suspended(hsi_ctrl->dev) || !hsi_ctrl->clock_enabled)
 		dev_dbg(hsi_ctrl->dev,
 			"hsi_read with HSI clocks OFF, clock_enabled = %d\n",
@@ -745,6 +745,7 @@ int hsi_ioctl(struct hsi_device *dev, unsigned int command, void *arg)
 	int err = 0;
 	int fifo = 0;
 	u8 ret;
+	struct hsi_platform_data *pdata;
 
 	if (unlikely((!dev) ||
 		     (!dev->ch) ||
@@ -953,6 +954,56 @@ int hsi_ioctl(struct hsi_device *dev, unsigned int command, void *arg)
 		hsi_outl_and(HSI_SET_WAKE_3_WIRES_MASK,	base,
 			     HSI_SYS_SET_WAKE_REG(port));
 		break;
+	case HSI_IOCTL_SET_HI_SPEED:
+		if (!arg) {
+			err = -EINVAL;
+			goto out;
+		}
+		hsi_ctrl->hsi_fclk_req = *(unsigned int *)arg ?
+					HSI_FCLK_HI_SPEED : HSI_FCLK_LOW_SPEED;
+
+		if (hsi_ctrl->hsi_fclk_req == hsi_ctrl->hsi_fclk_current) {
+			dev_dbg(hsi_ctrl->dev, "HSI FClk already @%ldHz\n",
+				 hsi_ctrl->hsi_fclk_current);
+			goto out;
+		}
+
+		if (hsi_is_controller_transfer_ongoing(hsi_ctrl)) {
+			err = -EBUSY;
+			goto out;
+		}
+		hsi_ctrl->clock_change_ongoing = true;
+		spin_unlock_bh(&hsi_ctrl->lock);
+
+		pdata = dev_get_platdata(hsi_ctrl->dev);
+
+		/* Set the HSI FCLK to requested value. */
+		err = pdata->device_scale(hsi_ctrl->dev, hsi_ctrl->dev,
+					  hsi_ctrl->hsi_fclk_req);
+		if (err < 0) {
+			dev_err(hsi_ctrl->dev, "%s: Cannot set HSI FClk to"
+				" %ldHz, err %d\n", __func__,
+				hsi_ctrl->hsi_fclk_req, err);
+		} else {
+			dev_info(hsi_ctrl->dev, "HSI FClk changed from %ldHz to"
+				 " %ldHz\n", hsi_ctrl->hsi_fclk_current,
+				 hsi_ctrl->hsi_fclk_req);
+			hsi_ctrl->hsi_fclk_current = hsi_ctrl->hsi_fclk_req;
+		}
+
+		spin_lock_bh(&hsi_ctrl->lock);
+		hsi_ctrl->clock_change_ongoing = false;
+
+		break;
+	case HSI_IOCTL_GET_SPEED:
+		if (!arg) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		*(unsigned long *)arg = hsi_ctrl->hsi_fclk_current;
+		break;
+
 	default:
 		err = -ENOIOCTLCMD;
 		break;
diff --git a/include/linux/hsi_char.h b/include/linux/hsi_char.h
index a85a3b0..1d87bcb 100644
--- a/include/linux/hsi_char.h
+++ b/include/linux/hsi_char.h
@@ -41,6 +41,8 @@
 #define CS_GET_FIFO_OCCUPANCY	CS_IOR(12, size_t)
 #define CS_GET_CAWAKELINE	CS_IOR(13, unsigned int)
 #define CS_SET_WAKE_RX_3WIRES_MODE	CS_IOR(14, unsigned int)
+#define CS_SET_HI_SPEED		CS_IOR(15, unsigned int)
+#define CS_GET_SPEED		CS_IOW(16, unsigned long)
 
 #define HSI_MODE_SLEEP		0
 #define HSI_MODE_STREAM		1
diff --git a/include/linux/hsi_driver_if.h b/include/linux/hsi_driver_if.h
index 6e7a0da..c7afe6b 100644
--- a/include/linux/hsi_driver_if.h
+++ b/include/linux/hsi_driver_if.h
@@ -38,6 +38,9 @@
 #define HSI_HSR_DIVISOR_AUTO		0x1000	/* Activate auto Rx */
 #define HSI_SSR_DIVISOR_USE_TIMEOUT	0x1001	/* De-activate auto-Rx (SSI) */
 
+#define HSI_SPEED_LOW_SPEED	0	/* Switch to 96MHz */
+#define HSI_SPEED_HI_SPEED	1	/* Switch to 192MHz */
+
 enum {
 	HSI_EVENT_BREAK_DETECTED = 0,
 	HSI_EVENT_ERROR,
@@ -64,6 +67,8 @@ enum {
 	HSI_IOCTL_GET_FIFO_OCCUPANCY, /* Get amount of words in RX FIFO */
 	HSI_IOCTL_SET_WAKE_RX_3WIRES_MODE, /* Enable RX wakeup 3-wires mode */
 	HSI_IOCTL_SET_WAKE_RX_4WIRES_MODE, /* Enable RX wakeup 4-wires mode */
+	HSI_IOCTL_SET_HI_SPEED, /* Change HSI Fclock (96MHz/192MHz) */
+	HSI_IOCTL_GET_SPEED, /* Get HSI Fclock (96MHz/192MHz) */
 };
 
 /* Forward references */