linux-kernel - [PATCH v2 15/15] powerpc/rcpm: add sleep support for T4/B4 chips

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Date:	Fri, 19 Apr 2013 18:47:48 +0800
From:	Zhao Chenhui <chenhui.zhao@...escale.com>
To:	<linuxppc-dev@...ts.ozlabs.org>
CC:	<linux-kernel@...r.kernel.org>
Subject: [PATCH v2 15/15] powerpc/rcpm: add sleep support for T4/B4 chips

From: Chen-Hui Zhao <chenhui.zhao@...escale.com>

RCPM unit controls the power managment of T4/B4 chips. Software can
access RCPM registers to put specific thread/core in PH10/PH15/PH20/PH30
state or put the device in LPM10/LPM20/LPM40 mode.

The RCPM unit supports several wake up sources through internal timers
and internal and external interrupts.

When the device enter sleep state, it will be put in LPM20 mode.
The command is "echo standby > /sys/power/state".

Signed-off-by: Zhao Chenhui <chenhui.zhao@...escale.com>
Signed-off-by: Li Yang <leoli@...escale.com>
Signed-off-by: Andy Fleming <afleming@...escale.com>
---
 arch/powerpc/sysdev/fsl_rcpm.c |   54 +++++++++++++++++++++++++++++++++++++---
 1 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_rcpm.c b/arch/powerpc/sysdev/fsl_rcpm.c
index fd789da..10e5cb3 100644
--- a/arch/powerpc/sysdev/fsl_rcpm.c
+++ b/arch/powerpc/sysdev/fsl_rcpm.c
@@ -20,6 +20,7 @@
 #include <asm/fsl_guts.h>
 
 static struct ccsr_rcpm __iomem *rcpm_regs;
+static struct ccsr_rcpm_v2 __iomem *rcpm2_regs;
 
 static int rcpm_suspend_enter(suspend_state_t state)
 {
@@ -53,6 +54,41 @@ static int rcpm_suspend_enter(suspend_state_t state)
 	return ret;
 }
 
+static int rcpm_v2_suspend_enter(suspend_state_t state)
+{
+	int ret = 0;
+
+	switch (state) {
+	case PM_SUSPEND_STANDBY:
+
+		/* clear previous LPM20 status */
+		setbits32(&rcpm2_regs->powmgtcsr, RCPM_POWMGTCSR_P_LPM20_ST);
+		/* enter LPM20 status */
+		setbits32(&rcpm2_regs->powmgtcsr, RCPM_POWMGTCSR_LPM20_RQ);
+
+		/* At this point, the device is in LPM20 status. */
+
+		/* resume ... */
+		ret = spin_event_timeout(
+		      (in_be32(&rcpm2_regs->powmgtcsr) & RCPM_POWMGTCSR_LPM20_ST)
+		      == 0, 10000, 10);
+		if (!ret) {
+			pr_err("%s: timeout waiting for LPM20 bit to be cleared\n",
+				__func__);
+			ret = -EINVAL;
+		}
+
+		break;
+
+	default:
+		ret = -EINVAL;
+
+	}
+
+	return ret;
+
+}
+
 static int rcpm_suspend_valid(suspend_state_t state)
 {
 	if (state == PM_SUSPEND_STANDBY)
@@ -63,16 +99,25 @@ static int rcpm_suspend_valid(suspend_state_t state)
 
 static const struct platform_suspend_ops rcpm_suspend_ops = {
 	.valid = rcpm_suspend_valid,
-	.enter = rcpm_suspend_enter,
 };
 
 static int rcpm_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 
-	rcpm_regs = of_iomap(np, 0);
-	if (!rcpm_regs)
-		return -ENOMEM;
+	if (of_device_is_compatible(np, "fsl,qoriq-rcpm-2.0")) {
+		rcpm2_regs = of_iomap(np, 0);
+		if (!rcpm2_regs)
+			return -ENOMEM;
+
+		rcpm_suspend_ops.enter = rcpm_v2_suspend_enter;
+	} else {
+		rcpm_regs = of_iomap(np, 0);
+		if (!rcpm_regs)
+			return -ENOMEM;
+
+		rcpm_suspend_ops.enter = rcpm_suspend_enter;
+	}
 
 	suspend_set_ops(&rcpm_suspend_ops);
 
@@ -82,6 +127,7 @@ static int rcpm_probe(struct platform_device *pdev)
 
 static const struct of_device_id rcpm_ids[] = {
 	{ .compatible = "fsl,qoriq-rcpm-1.0", },
+	{ .compatible = "fsl,qoriq-rcpm-2.0", },
 	{ },
 };
 
-- 
1.7.3


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