mfd: db8500 OPP and sleep handling update

This updates the operating point handling code by:

- Supporting the DDR OPP retention state.
- Supporting another low operating point named
  APE_50_PARTLY_25_OPP
- Adding an interface to figure out if the sleep state change
  was properly achieved.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 72 insertions, 1 deletions

diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
index 13856392cb2..8056968da20 100644
--- a/drivers/mfd/db8500-prcmu.c
+++ b/drivers/mfd/db8500-prcmu.c
@@ -343,11 +343,13 @@ static struct {
  * mb1_transfer - state needed for mailbox 1 communication.
  * @lock:	The transaction lock.
  * @work:	The transaction completion structure.
+ * @ape_opp:	The current APE OPP.
  * @ack:	Reply ("acknowledge") data.
  */
 static struct {
 	struct mutex lock;
 	struct completion work;
+	u8 ape_opp;
 	struct {
 		u8 header;
 		u8 arm_opp;
@@ -816,6 +818,11 @@ int db8500_prcmu_set_power_state(u8 state, bool keep_ulp_clk, bool keep_ap_pll)
 	return 0;
 }
 
+u8 db8500_prcmu_get_power_state_result(void)
+{
+	return readb(tcdm_base + PRCM_ACK_MB0_AP_PWRSTTR_STATUS);
+}
+
 /* This function should only be called while mb0_transfer.lock is held. */
 static void config_wakeups(void)
 {
@@ -965,6 +972,52 @@ int db8500_prcmu_set_ddr_opp(u8 opp)
 	return 0;
 }
 
+/* Divide the frequency of certain clocks by 2 for APE_50_PARTLY_25_OPP. */
+static void request_even_slower_clocks(bool enable)
+{
+	void __iomem *clock_reg[] = {
+		PRCM_ACLK_MGT,
+		PRCM_DMACLK_MGT
+	};
+	unsigned long flags;
+	unsigned int i;
+
+	spin_lock_irqsave(&clk_mgt_lock, flags);
+
+	/* Grab the HW semaphore. */
+	while ((readl(PRCM_SEM) & PRCM_SEM_PRCM_SEM) != 0)
+		cpu_relax();
+
+	for (i = 0; i < ARRAY_SIZE(clock_reg); i++) {
+		u32 val;
+		u32 div;
+
+		val = readl(clock_reg[i]);
+		div = (val & PRCM_CLK_MGT_CLKPLLDIV_MASK);
+		if (enable) {
+			if ((div <= 1) || (div > 15)) {
+				pr_err("prcmu: Bad clock divider %d in %s\n",
+					div, __func__);
+				goto unlock_and_return;
+			}
+			div <<= 1;
+		} else {
+			if (div <= 2)
+				goto unlock_and_return;
+			div >>= 1;
+		}
+		val = ((val & ~PRCM_CLK_MGT_CLKPLLDIV_MASK) |
+			(div & PRCM_CLK_MGT_CLKPLLDIV_MASK));
+		writel(val, clock_reg[i]);
+	}
+
+unlock_and_return:
+	/* Release the HW semaphore. */
+	writel(0, PRCM_SEM);
+
+	spin_unlock_irqrestore(&clk_mgt_lock, flags);
+}
+
 /**
  * db8500_set_ape_opp - set the appropriate APE OPP
  * @opp: The new APE operating point to which transition is to be made
@@ -976,14 +1029,24 @@ int db8500_prcmu_set_ape_opp(u8 opp)
 {
 	int r = 0;
 
+	if (opp == mb1_transfer.ape_opp)
+		return 0;
+
 	mutex_lock(&mb1_transfer.lock);
 
+	if (mb1_transfer.ape_opp == APE_50_PARTLY_25_OPP)
+		request_even_slower_clocks(false);
+
+	if ((opp != APE_100_OPP) && (mb1_transfer.ape_opp != APE_100_OPP))
+		goto skip_message;
+
 	while (readl(PRCM_MBOX_CPU_VAL) & MBOX_BIT(1))
 		cpu_relax();
 
 	writeb(MB1H_ARM_APE_OPP, (tcdm_base + PRCM_MBOX_HEADER_REQ_MB1));
 	writeb(ARM_NO_CHANGE, (tcdm_base + PRCM_REQ_MB1_ARM_OPP));
-	writeb(opp, (tcdm_base + PRCM_REQ_MB1_APE_OPP));
+	writeb(((opp == APE_50_PARTLY_25_OPP) ? APE_50_OPP : opp),
+		(tcdm_base + PRCM_REQ_MB1_APE_OPP));
 
 	writel(MBOX_BIT(1), PRCM_MBOX_CPU_SET);
 	wait_for_completion(&mb1_transfer.work);
@@ -992,6 +1055,13 @@ int db8500_prcmu_set_ape_opp(u8 opp)
 		(mb1_transfer.ack.ape_opp != opp))
 		r = -EIO;
 
+skip_message:
+	if ((!r && (opp == APE_50_PARTLY_25_OPP)) ||
+		(r && (mb1_transfer.ape_opp == APE_50_PARTLY_25_OPP)))
+		request_even_slower_clocks(true);
+	if (!r)
+		mb1_transfer.ape_opp = opp;
+
 	mutex_unlock(&mb1_transfer.lock);
 
 	return r;
@@ -2631,6 +2701,7 @@ void __init db8500_prcmu_early_init(void)
 	init_completion(&mb0_transfer.ac_wake_work);
 	mutex_init(&mb1_transfer.lock);
 	init_completion(&mb1_transfer.work);
+	mb1_transfer.ape_opp = APE_NO_CHANGE;
 	mutex_init(&mb2_transfer.lock);
 	init_completion(&mb2_transfer.work);
 	spin_lock_init(&mb2_transfer.auto_pm_lock);