ARM: tegra: assembler code for LP3

Configure the flow controller for clockgating and enter WFI

Based on work by:

Colin Cross <ccross@android.com>
Gary King <gking@nvidia.com>
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/mach-tegra/sleep.S

+/*
+ * arch/arm/mach-tegra/sleep.S
+ *
+ * Copyright (c) 2010-2011, NVIDIA Corporation.
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * Author: Colin Cross <ccross@android.com>
+ *         Gary King <gking@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include <linux/linkage.h>
+#include <mach/io.h>
+#include <mach/iomap.h>
+
+#include "flowctrl.h"
+
+#define TEGRA_FLOW_CTRL_VIRT (TEGRA_FLOW_CTRL_BASE - IO_PPSB_PHYS \
+					+ IO_PPSB_VIRT)
+
+/* returns the offset of the flow controller halt register for a cpu */
+.macro cpu_to_halt_reg rd, rcpu
+	cmp	\rcpu, #0
+	subne	\rd, \rcpu, #1
+	movne	\rd, \rd, lsl #3
+	addne	\rd, \rd, #0x14
+	moveq	\rd, #0
+.endm
+
+/* returns the offset of the flow controller csr register for a cpu */
+.macro cpu_to_csr_reg rd, rcpu
+	cmp	\rcpu, #0
+	subne	\rd, \rcpu, #1
+	movne	\rd, \rd, lsl #3
+	addne	\rd, \rd, #0x18
+	moveq	\rd, #8
+.endm
+
+/* returns the ID of the current processor */
+.macro cpu_id, rd
+	mrc	p15, 0, \rd, c0, c0, 5
+	and	\rd, \rd, #0xF
+.endm
+
+/* loads a 32-bit value into a register without a data access */
+.macro mov32, reg, val
+	movw	\reg, #:lower16:\val
+	movt	\reg, #:upper16:\val
+.endm
+
+/*
+ * tegra_cpu_wfi
+ *
+ * puts current CPU in clock-gated wfi using the flow controller
+ *
+ * corrupts r0-r3
+ * must be called with MMU on
+ */
+
+ENTRY(tegra_cpu_wfi)
+	cpu_id	r0
+	cpu_to_halt_reg r1, r0
+	cpu_to_csr_reg r2, r0
+	mov32	r0, TEGRA_FLOW_CTRL_VIRT
+	mov	r3, #FLOW_CTRL_CSR_INTR_FLAG | FLOW_CTRL_CSR_EVENT_FLAG
+	str	r3, [r0, r2]	@ clear event & interrupt status
+	mov	r3, #FLOW_CTRL_WAIT_FOR_INTERRUPT | FLOW_CTRL_JTAG_RESUME
+	str	r3, [r0, r1]	@ put flow controller in wait irq mode
+	dsb
+	wfi
+	mov	r3, #0
+	str	r3, [r0, r1]	@ clear flow controller halt status
+	mov	r3, #FLOW_CTRL_CSR_INTR_FLAG | FLOW_CTRL_CSR_EVENT_FLAG
+	str	r3, [r0, r2]	@ clear event & interrupt status
+	dsb
+	mov	pc, lr
+ENDPROC(tegra_cpu_wfi)
+