ARM: OMAP AM33xx: PRM: add PRM support

As far as PRM/CM/PRCM modules are concerned, AM33XX device is
different than OMAP3 and OMAP4 architectures; so we need to handle it
separately.  This patch adds support for the PRM APIs required for
AM33XX device.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: separated the PRM parts of "ARM: OMAP3+: am33xx: Add
 powerdomain & PRM support" into this patch; fixed Makefile prm33xx.o
 location; cleaned up some checkpatch violations; updated for 3.5]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 135 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/prm33xx.c b/arch/arm/mach-omap2/prm33xx.c
new file mode 100644
index 000000000000..e7dbb6cf1255
--- /dev/null
+++ b/arch/arm/mach-omap2/prm33xx.c
@@ -0,0 +1,135 @@
+/*
+ * AM33XX PRM functions
+ *
+ * Copyright (C) 2011-2012 Texas Instruments Incorporated - http://www.ti.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <plat/common.h>
+
+#include "common.h"
+#include "prm33xx.h"
+#include "prm-regbits-33xx.h"
+
+/* Read a register in a PRM instance */
+u32 am33xx_prm_read_reg(s16 inst, u16 idx)
+{
+	return __raw_readl(prm_base + inst + idx);
+}
+
+/* Write into a register in a PRM instance */
+void am33xx_prm_write_reg(u32 val, s16 inst, u16 idx)
+{
+	__raw_writel(val, prm_base + inst + idx);
+}
+
+/* Read-modify-write a register in PRM. Caller must lock */
+u32 am33xx_prm_rmw_reg_bits(u32 mask, u32 bits, s16 inst, s16 idx)
+{
+	u32 v;
+
+	v = am33xx_prm_read_reg(inst, idx);
+	v &= ~mask;
+	v |= bits;
+	am33xx_prm_write_reg(v, inst, idx);
+
+	return v;
+}
+
+/**
+ * am33xx_prm_is_hardreset_asserted - read the HW reset line state of
+ * submodules contained in the hwmod module
+ * @shift: register bit shift corresponding to the reset line to check
+ * @inst: CM instance register offset (*_INST macro)
+ * @rstctrl_offs: RM_RSTCTRL register address offset for this module
+ *
+ * Returns 1 if the (sub)module hardreset line is currently asserted,
+ * 0 if the (sub)module hardreset line is not currently asserted, or
+ * -EINVAL upon parameter error.
+ */
+int am33xx_prm_is_hardreset_asserted(u8 shift, s16 inst, u16 rstctrl_offs)
+{
+	u32 v;
+
+	v = am33xx_prm_read_reg(inst, rstctrl_offs);
+	v &= 1 << shift;
+	v >>= shift;
+
+	return v;
+}
+
+/**
+ * am33xx_prm_assert_hardreset - assert the HW reset line of a submodule
+ * @shift: register bit shift corresponding to the reset line to assert
+ * @inst: CM instance register offset (*_INST macro)
+ * @rstctrl_reg: RM_RSTCTRL register address for this module
+ *
+ * Some IPs like dsp, ipu or iva contain processors that require an HW
+ * reset line to be asserted / deasserted in order to fully enable the
+ * IP.  These modules may have multiple hard-reset lines that reset
+ * different 'submodules' inside the IP block.  This function will
+ * place the submodule into reset.  Returns 0 upon success or -EINVAL
+ * upon an argument error.
+ */
+int am33xx_prm_assert_hardreset(u8 shift, s16 inst, u16 rstctrl_offs)
+{
+	u32 mask = 1 << shift;
+
+	am33xx_prm_rmw_reg_bits(mask, mask, inst, rstctrl_offs);
+
+	return 0;
+}
+
+/**
+ * am33xx_prm_deassert_hardreset - deassert a submodule hardreset line and
+ * wait
+ * @shift: register bit shift corresponding to the reset line to deassert
+ * @inst: CM instance register offset (*_INST macro)
+ * @rstctrl_reg: RM_RSTCTRL register address for this module
+ * @rstst_reg: RM_RSTST register address for this module
+ *
+ * Some IPs like dsp, ipu or iva contain processors that require an HW
+ * reset line to be asserted / deasserted in order to fully enable the
+ * IP.  These modules may have multiple hard-reset lines that reset
+ * different 'submodules' inside the IP block.  This function will
+ * take the submodule out of reset and wait until the PRCM indicates
+ * that the reset has completed before returning.  Returns 0 upon success or
+ * -EINVAL upon an argument error, -EEXIST if the submodule was already out
+ * of reset, or -EBUSY if the submodule did not exit reset promptly.
+ */
+int am33xx_prm_deassert_hardreset(u8 shift, s16 inst,
+		u16 rstctrl_offs, u16 rstst_offs)
+{
+	int c;
+	u32 mask = 1 << shift;
+
+	/* Check the current status to avoid  de-asserting the line twice */
+	if (am33xx_prm_is_hardreset_asserted(shift, inst, rstctrl_offs) == 0)
+		return -EEXIST;
+
+	/* Clear the reset status by writing 1 to the status bit */
+	am33xx_prm_rmw_reg_bits(0xffffffff, mask, inst, rstst_offs);
+	/* de-assert the reset control line */
+	am33xx_prm_rmw_reg_bits(mask, 0, inst, rstctrl_offs);
+	/* wait the status to be set */
+
+	omap_test_timeout(am33xx_prm_is_hardreset_asserted(shift, inst,
+							   rstst_offs),
+			  MAX_MODULE_HARDRESET_WAIT, c);
+
+	return (c == MAX_MODULE_HARDRESET_WAIT) ? -EBUSY : 0;
+}