ARC: irqflags - Interrupt enabling/disabling at in-core intc

ARC700 has an in-core intc which provides 2 priorities (a.k.a.) "levels"
of interrupts (per IRQ) hencforth referred to as L1/L2 interrupts.

CPU flags register STATUS32 has Interrupt Enable bits per level (E1/E2)
to globally enable (or disable) all IRQs at a level. Hence the
implementation of arch_local_irq_{save,restore,enable,disable}( )

The STATUS32 reg can be r/w only using the AUX Interface of ARC, hence
the use of LR/SR instructions. Further, E1/E2 bits in there can only be
updated using the FLAG insn.

The intc supports 32 interrupts - and per IRQ enabling is controlled by
a bit in the AUX_IENABLE register, hence the implmentation of
arch_{,un}mask_irq( ) routines.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 114 insertions, 0 deletions

diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
new file mode 100644
index 000000000000..8ca8faf4b80e
--- /dev/null
+++ b/arch/arc/include/asm/arcregs.h
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARC_ARCREGS_H
+#define _ASM_ARC_ARCREGS_H
+
+#ifdef __KERNEL__
+
+/* status32 Bits Positions */
+#define STATUS_H_BIT		0	/* CPU Halted */
+#define STATUS_E1_BIT		1	/* Int 1 enable */
+#define STATUS_E2_BIT		2	/* Int 2 enable */
+#define STATUS_A1_BIT		3	/* Int 1 active */
+#define STATUS_A2_BIT		4	/* Int 2 active */
+#define STATUS_AE_BIT		5	/* Exception active */
+#define STATUS_DE_BIT		6	/* PC is in delay slot */
+#define STATUS_U_BIT		7	/* User/Kernel mode */
+#define STATUS_L_BIT		12	/* Loop inhibit */
+
+/* These masks correspond to the status word(STATUS_32) bits */
+#define STATUS_H_MASK		(1<<STATUS_H_BIT)
+#define STATUS_E1_MASK		(1<<STATUS_E1_BIT)
+#define STATUS_E2_MASK		(1<<STATUS_E2_BIT)
+#define STATUS_A1_MASK		(1<<STATUS_A1_BIT)
+#define STATUS_A2_MASK		(1<<STATUS_A2_BIT)
+#define STATUS_AE_MASK		(1<<STATUS_AE_BIT)
+#define STATUS_DE_MASK		(1<<STATUS_DE_BIT)
+#define STATUS_U_MASK		(1<<STATUS_U_BIT)
+#define STATUS_L_MASK		(1<<STATUS_L_BIT)
+
+/* Auxiliary registers */
+#define AUX_IDENTITY		4
+#define AUX_INTR_VEC_BASE	0x25
+#define AUX_IRQ_LEV		0x200	/* IRQ Priority: L1 or L2 */
+#define AUX_IRQ_HINT		0x201	/* For generating Soft Interrupts */
+#define AUX_IRQ_LV12		0x43	/* interrupt level register */
+
+#define AUX_IENABLE		0x40c
+#define AUX_ITRIGGER		0x40d
+#define AUX_IPULSE		0x415
+
+#ifndef __ASSEMBLY__
+
+/*
+ ******************************************************************
+ *      Inline ASM macros to read/write AUX Regs
+ *      Essentially invocation of lr/sr insns from "C"
+ */
+
+#if 1
+
+#define read_aux_reg(reg)	__builtin_arc_lr(reg)
+
+/* gcc builtin sr needs reg param to be long immediate */
+#define write_aux_reg(reg_immed, val)		\
+		__builtin_arc_sr((unsigned int)val, reg_immed)
+
+#else
+
+#define read_aux_reg(reg)		\
+({					\
+	unsigned int __ret;		\
+	__asm__ __volatile__(		\
+	"	lr    %0, [%1]"		\
+	: "=r"(__ret)			\
+	: "i"(reg));			\
+	__ret;				\
+})
+
+/*
+ * Aux Reg address is specified as long immediate by caller
+ * e.g.
+ *    write_aux_reg(0x69, some_val);
+ * This generates tightest code.
+ */
+#define write_aux_reg(reg_imm, val)	\
+({					\
+	__asm__ __volatile__(		\
+	"	sr   %0, [%1]	\n"	\
+	:				\
+	: "ir"(val), "i"(reg_imm));	\
+})
+
+/*
+ * Aux Reg address is specified in a variable
+ *  * e.g.
+ *      reg_num = 0x69
+ *      write_aux_reg2(reg_num, some_val);
+ * This has to generate glue code to load the reg num from
+ *  memory to a reg hence not recommended.
+ */
+#define write_aux_reg2(reg_in_var, val)		\
+({						\
+	unsigned int tmp;			\
+						\
+	__asm__ __volatile__(			\
+	"	ld   %0, [%2]	\n\t"		\
+	"	sr   %1, [%0]	\n\t"		\
+	: "=&r"(tmp)				\
+	: "r"(val), "memory"(&reg_in_var));	\
+})
+
+#endif
+
+#endif /* __ASEMBLY__ */
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_ARC_ARCREGS_H */