tegra: Make bitfield.h a common file

This is needed by both T2x and T3x.

BUG=chromium-os:19004
TEST=build and boot on seaboard

Change-Id: I03cb8e7b189cae0efb58d1ceed55a1e0dcd57c7f
Reviewed-on: http://gerrit.chromium.org/gerrit/8636
Reviewed-by: Che-Liang Chiou <clchiou@chromium.org>
Reviewed-by: Tom Warren <twarren@nvidia.com>
Tested-by: Simon Glass <sjg@chromium.org>

1 files changed, 163 insertions, 0 deletions

diff --git a/arch/arm/include/asm/arch-tegra/bitfield.h b/arch/arm/include/asm/arch-tegra/bitfield.h
new file mode 100644
index 0000000000..7e394f3800
--- /dev/null
+++ b/arch/arm/include/asm/arch-tegra/bitfield.h
@@ -0,0 +1,163 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef __TEGRA2_BITFIELD_H
+#define __TEGRA2_BITFIELD_H
+
+/*
+ * Macros for working with bit fields. To use these, set things up like this:
+ *
+ * #define UART_PA_START 0x67000000	Physical address of UART
+ * #define UART_FBCON_RANGE  5:3	Bit range for the FBCON field
+ * enum {				An enum with allowed values
+ *	UART_FBCON_OFF,
+ *	UART_FBCON_ON,
+ *	UART_FBCON_MULTI,
+ *	UART_FBCON_SLAVE,
+ * };
+ * struct uart_ctlr *uart = (struct uart_ctlr *)UART_PA_START;
+ *
+ * This defines a bit field of 3 bits starting at bit 5 and extending down
+ * to bit 3, i.e. 5:3
+ *
+ * Then:
+ *    bf_unpack(UART_FBCON)
+ *	- return the value of bits 5:3 (shifted down to bits 2:0)
+ *
+ *    bf_pack(UART_FBCON, 4)
+ *	- return a word with that field set to 4 (so in this case (4 << 3))
+ *
+ *    bf_update(UART_FBCON, word, val)
+ *	- update a field within word so that its value is val.
+ *
+ *    bf_enum_writel(UART_FBCON, MULTI, &uart->fbcon)
+ *	- set the UART's FBCON field to MULTI
+ *
+ *
+ * Why have bitfield macros?
+ *   1. Reability
+ *   2. Maintainability
+ *   3. Less error prone
+ *
+ * For example, this:
+ *
+ *	int RegVal = 0;
+ *	RegVal= readl(UsbBase+USB_SUSP_CTRL);
+ *	RegVal |= Bit11;
+ *	writel(RegVal, UsbBase+USB_SUSP_CTRL);
+ *	if(UsbBase == NV_ADDRESS_MAP_USB3_BASE)
+ *	{
+ *		RegVal = readl(UsbBase+USB_SUSP_CTRL);
+ *		RegVal |= Bit12;
+ *		writel(RegVal, UsbBase+USB_SUSP_CTRL);
+ *	}
+ *
+ * becomes this:
+ *
+ *	bitfield_writel(UTMIP_RESET, 1, &usbctlr->susp_ctrl);
+ *	if (id == PERIPH_ID_USB3)
+ *		bitfield_writel(UTMIP_PHY_ENB, 1, &usbctlr->susp_ctrl);
+ */
+
+/* Returns the low bit of the bitfield */
+#define BITFIELD_LOWBIT(range)	((0 ? range) & 0x1f)
+
+/* Returns the high bit of the bitfield */
+#define BITFIELD_HIGHBIT(range)	(1 ? range)
+
+/* Returns the width of the bitfield (in bits) */
+#define BITFIELD_WIDTH(range)	\
+	(BITFIELD_HIGHBIT(range) - BITFIELD_LOWBIT(range) + 1)
+
+
+/*
+ * Returns the number of bits the bitfield needs to be shifted left to pack it.
+ * This is just the same as the low bit.
+ */
+#define bf_shift(field)	BITFIELD_LOWBIT(field ## _RANGE)
+
+/* Returns the unshifted mask for the field (i.e. LSB of mask is bit 0) */
+#define bf_rawmask(field) (0xfffffffful >> \
+		(32 - BITFIELD_WIDTH(field ## _RANGE)))
+
+/* Returns the mask for a field. Clear these bits to zero the field */
+#define bf_mask(field) \
+		(bf_rawmask(field) << (bf_shift(field)))
+
+/* Unpacks and returns a value extracted from a field */
+#define bf_unpack(field, word) \
+	(((unsigned)(word) >> bf_shift(field)) & bf_rawmask(field))
+
+/*
+ * Packs a value into a field - this masks the value to ensure it does not
+ * overflow into another field.
+ */
+#define bf_pack(field, value) \
+	((((unsigned)(value)) & bf_rawmask(field)) \
+		<< bf_shift(field))
+
+/* Sets the value of a field in a word to the given value */
+#define bf_update(field, word, value)		\
+	((word) = ((word) & ~bf_mask(field)) |	\
+		bf_pack(field, value))
+
+/*
+ * Sets the value of a field in a register to the given value using
+ * readl/writel
+ */
+#define bf_writel(field, value, reg) ({		\
+	u32 *__reg = (u32 *)(reg);			\
+	u32 __oldval = readl(__reg);			\
+	bf_update(field, __oldval, value);		\
+	writel(__oldval, __reg);				\
+	})
+
+/* Unpacks a field from a register using readl */
+#define bf_readl(field, reg)			\
+	bf_unpack(field, readl(reg))
+
+/*
+ * Clears a field in a register using writel - like
+ * bf_writel(field, 0, reg)
+ */
+#define bf_clearl(field, reg) bf_writel(field, 0, reg)
+
+/*
+ * Sets the value of a field in a register to the given enum.
+ *
+ * The enum should have the field as a prefix.
+ */
+#define bf_enum(field, _enum) bf_pack(field, field ## _ ## _enum)
+
+/*
+ * Sets the value of a field in a register to the given enum.
+ *
+ * The enum should have the field as a prefix.
+ */
+#define bf_enum_writel(field, _enum, reg) \
+		bf_writel(field, field ## _ ## _enum, reg)
+
+/*
+ * Return a word with the bitfield set to all ones.
+ */
+#define bf_ones(field) bf_mask(field)
+
+#endif