ARM: ux500: move PM-related PRCMU functions to machine

We are trying to decompose and decentralize the code in
the DB8500 PRCMU out into subdrivers. The code moved in
this patch concerns a group of functions used for
decoupling and recoupling the IRQs from the GIC. During
sleep and idle the Ux500 system will transfer all IRQ
handling to the PRCMU using these functions.

Basically we are left with the two alternatives of code
placement as:

- arch/arm/mach-ux500/pm.c - this because the code is
  closely related to the GIC, and takes ownership of
  some of the registers from the PRCMU related to this
  PM functionality.

- drivers/mfd/db8500-prcmu-pm.c - because the code is
  affecting stuff in the PRCMU register range. But then
  this code needs to remap and handle GIC registers.

This patch implementation is taking the first approach.

Currently the cpuidle driver is the only piece of code
using this set of functions, but it will later also be
used by the suspend/resume code which is currently under
review.

The header file is moved to:
<linux/platform_data/arm-ux500-pm.h>
The function prototypes need to be placed in a globally
visible header since the CPUidle code is planned to move
out to drivers/cpuidle.

Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Acked-by: Rickard Andersson <rickard.andersson@stericsson.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 167 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/pm.c b/arch/arm/mach-ux500/pm.c
new file mode 100644
index 0000000..6949a13
--- /dev/null
+++ b/arch/arm/mach-ux500/pm.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010-2013
+ * Author: Rickard Andersson <rickard.andersson@stericsson.com> for
+ *         ST-Ericsson.
+ * Author: Daniel Lezcano <daniel.lezcano@linaro.org> for Linaro.
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/irqchip/arm-gic.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/platform_data/arm-ux500-pm.h>
+
+#include <mach/hardware.h>
+
+/* ARM WFI Standby signal register */
+#define PRCM_ARM_WFI_STANDBY    (prcmu_base + 0x130)
+#define PRCM_ARM_WFI_STANDBY_WFI0		0x08
+#define PRCM_ARM_WFI_STANDBY_WFI1		0x10
+#define PRCM_IOCR		(prcmu_base + 0x310)
+#define PRCM_IOCR_IOFORCE			0x1
+
+/* Dual A9 core interrupt management unit registers */
+#define PRCM_A9_MASK_REQ	(prcmu_base + 0x328)
+#define PRCM_A9_MASK_REQ_PRCM_A9_MASK_REQ	0x1
+
+#define PRCM_A9_MASK_ACK	(prcmu_base + 0x32c)
+#define PRCM_ARMITMSK31TO0	(prcmu_base + 0x11c)
+#define PRCM_ARMITMSK63TO32	(prcmu_base + 0x120)
+#define PRCM_ARMITMSK95TO64	(prcmu_base + 0x124)
+#define PRCM_ARMITMSK127TO96	(prcmu_base + 0x128)
+#define PRCM_POWER_STATE_VAL	(prcmu_base + 0x25C)
+#define PRCM_ARMITVAL31TO0	(prcmu_base + 0x260)
+#define PRCM_ARMITVAL63TO32	(prcmu_base + 0x264)
+#define PRCM_ARMITVAL95TO64	(prcmu_base + 0x268)
+#define PRCM_ARMITVAL127TO96	(prcmu_base + 0x26C)
+
+static void __iomem *prcmu_base;
+
+/* This function decouple the gic from the prcmu */
+int prcmu_gic_decouple(void)
+{
+	u32 val = readl(PRCM_A9_MASK_REQ);
+
+	/* Set bit 0 register value to 1 */
+	writel(val | PRCM_A9_MASK_REQ_PRCM_A9_MASK_REQ,
+	       PRCM_A9_MASK_REQ);
+
+	/* Make sure the register is updated */
+	readl(PRCM_A9_MASK_REQ);
+
+	/* Wait a few cycles for the gic mask completion */
+	udelay(1);
+
+	return 0;
+}
+
+/* This function recouple the gic with the prcmu */
+int prcmu_gic_recouple(void)
+{
+	u32 val = readl(PRCM_A9_MASK_REQ);
+
+	/* Set bit 0 register value to 0 */
+	writel(val & ~PRCM_A9_MASK_REQ_PRCM_A9_MASK_REQ, PRCM_A9_MASK_REQ);
+
+	return 0;
+}
+
+#define PRCMU_GIC_NUMBER_REGS 5
+
+/*
+ * This function checks if there are pending irq on the gic. It only
+ * makes sense if the gic has been decoupled before with the
+ * db8500_prcmu_gic_decouple function. Disabling an interrupt only
+ * disables the forwarding of the interrupt to any CPU interface. It
+ * does not prevent the interrupt from changing state, for example
+ * becoming pending, or active and pending if it is already
+ * active. Hence, we have to check the interrupt is pending *and* is
+ * active.
+ */
+bool prcmu_gic_pending_irq(void)
+{
+	u32 pr; /* Pending register */
+	u32 er; /* Enable register */
+	void __iomem *dist_base = __io_address(U8500_GIC_DIST_BASE);
+	int i;
+
+	/* 5 registers. STI & PPI not skipped */
+	for (i = 0; i < PRCMU_GIC_NUMBER_REGS; i++) {
+
+		pr = readl_relaxed(dist_base + GIC_DIST_PENDING_SET + i * 4);
+		er = readl_relaxed(dist_base + GIC_DIST_ENABLE_SET + i * 4);
+
+		if (pr & er)
+			return true; /* There is a pending interrupt */
+	}
+
+	return false;
+}
+
+/*
+ * This function checks if there are pending interrupt on the
+ * prcmu which has been delegated to monitor the irqs with the
+ * db8500_prcmu_copy_gic_settings function.
+ */
+bool prcmu_pending_irq(void)
+{
+	u32 it, im;
+	int i;
+
+	for (i = 0; i < PRCMU_GIC_NUMBER_REGS - 1; i++) {
+		it = readl(PRCM_ARMITVAL31TO0 + i * 4);
+		im = readl(PRCM_ARMITMSK31TO0 + i * 4);
+		if (it & im)
+			return true; /* There is a pending interrupt */
+	}
+
+	return false;
+}
+
+/*
+ * This function checks if the specified cpu is in in WFI. It's usage
+ * makes sense only if the gic is decoupled with the db8500_prcmu_gic_decouple
+ * function. Of course passing smp_processor_id() to this function will
+ * always return false...
+ */
+bool prcmu_is_cpu_in_wfi(int cpu)
+{
+	return readl(PRCM_ARM_WFI_STANDBY) & cpu ? PRCM_ARM_WFI_STANDBY_WFI1 :
+		     PRCM_ARM_WFI_STANDBY_WFI0;
+}
+
+/*
+ * This function copies the gic SPI settings to the prcmu in order to
+ * monitor them and abort/finish the retention/off sequence or state.
+ */
+int prcmu_copy_gic_settings(void)
+{
+	u32 er; /* Enable register */
+	void __iomem *dist_base = __io_address(U8500_GIC_DIST_BASE);
+	int i;
+
+	/* We skip the STI and PPI */
+	for (i = 0; i < PRCMU_GIC_NUMBER_REGS - 1; i++) {
+		er = readl_relaxed(dist_base +
+				   GIC_DIST_ENABLE_SET + (i + 1) * 4);
+		writel(er, PRCM_ARMITMSK31TO0 + i * 4);
+	}
+
+	return 0;
+}
+
+void __init ux500_pm_init(u32 phy_base, u32 size)
+{
+	prcmu_base = ioremap(phy_base, size);
+	if (!prcmu_base) {
+		pr_err("could not remap PRCMU for PM functions\n");
+		return;
+	}
+	/*
+	 * On watchdog reboot the GIC is in some cases decoupled.
+	 * This will make sure that the GIC is correctly configured.
+	 */
+	prcmu_gic_recouple();
+}