AArch32: Add assembly helpers

This patch adds various assembly helpers for AArch32 like :

* cache management : Functions to flush, invalidate and clean
cache by MVA. Also helpers to do cache operations by set-way
are also added.

* stack management: Macros to declare stack and get the current
stack corresponding to current CPU.

* Misc: Macros to access co processor registers in AArch32,
macros to define functions in assembly, assert macros, generic
`do_panic()` implementation and function to zero block of memory.

Change-Id: I7b78ca3f922c0eda39beb9786b7150e9193425be

2 files changed, 297 insertions, 0 deletions

diff --git a/lib/aarch32/cache_helpers.S b/lib/aarch32/cache_helpers.S
new file mode 100644
index 00000000..d0e5cd06
--- /dev/null
+++ b/lib/aarch32/cache_helpers.S
@@ -0,0 +1,237 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+
+	.globl	flush_dcache_range
+	.globl	clean_dcache_range
+	.globl	inv_dcache_range
+	.globl	dcsw_op_louis
+	.globl	dcsw_op_all
+	.globl	dcsw_op_level1
+	.globl	dcsw_op_level2
+	.globl	dcsw_op_level3
+
+/*
+ * This macro can be used for implementing various data cache operations `op`
+ */
+.macro do_dcache_maintenance_by_mva op, coproc, opc1, CRn, CRm, opc2
+	dcache_line_size r2, r3
+	add	r1, r0, r1
+	sub	r3, r2, #1
+	bic	r0, r0, r3
+loop_\op:
+	stcopr	r0, \coproc, \opc1, \CRn, \CRm, \opc2
+	add	r0, r0, r2
+	cmp	r0, r1
+	blo	loop_\op
+	dsb	sy
+	bx	lr
+.endm
+
+	/* ------------------------------------------
+	 * Clean+Invalidate from base address till
+	 * size. 'r0' = addr, 'r1' = size
+	 * ------------------------------------------
+	 */
+func flush_dcache_range
+	do_dcache_maintenance_by_mva cimvac, DCCIMVAC
+endfunc flush_dcache_range
+
+	/* ------------------------------------------
+	 * Clean from base address till size.
+	 * 'r0' = addr, 'r1' = size
+	 * ------------------------------------------
+	 */
+func clean_dcache_range
+	do_dcache_maintenance_by_mva cmvac, DCCMVAC
+endfunc clean_dcache_range
+
+	/* ------------------------------------------
+	 * Invalidate from base address till
+	 * size. 'r0' = addr, 'r1' = size
+	 * ------------------------------------------
+	 */
+func inv_dcache_range
+	do_dcache_maintenance_by_mva imvac, DCIMVAC
+endfunc inv_dcache_range
+
+	/* ----------------------------------------------------------------
+	 * Data cache operations by set/way to the level specified
+	 *
+	 * The main function, do_dcsw_op requires:
+	 * r0: The operation type (DC_OP_ISW, DC_OP_CISW, DC_OP_CSW),
+	 * as defined in arch.h
+	 * r1: The cache level to begin operation from
+	 * r2: clidr_el1
+	 * r3: The last cache level to operate on
+	 * and will carry out the operation on each data cache from level 0
+	 * to the level in r3 in sequence
+	 *
+	 * The dcsw_op macro sets up the r2 and r3 parameters based on
+	 * clidr_el1 cache information before invoking the main function
+	 * ----------------------------------------------------------------
+	 */
+
+	.macro	dcsw_op shift, fw, ls
+	ldcopr	r2, CLIDR
+	ubfx	r3, r2, \shift, \fw
+	lsl	r3, r3, \ls
+	mov	r1, #0
+	b	do_dcsw_op
+	.endm
+
+func do_dcsw_op
+	push	{r4-r12,lr}
+	adr	r11, dcsw_loop_table	// compute cache op based on the operation type
+	add	r6, r11, r0, lsl #3	// cache op is 2x32-bit instructions
+loop1:
+	add	r10, r1, r1, LSR #1	// Work out 3x current cache level
+	mov	r12, r2, LSR r10	// extract cache type bits from clidr
+	and	r12, r12, #7   		// mask the bits for current cache only
+	cmp	r12, #2			// see what cache we have at this level
+	blt	level_done      	// no cache or only instruction cache at this level
+
+	stcopr	r1, CSSELR		// select current cache level in csselr
+	isb				// isb to sych the new cssr&csidr
+	ldcopr	r12, CCSIDR		// read the new ccsidr
+	and	r10, r12, #7   		// extract the length of the cache lines
+	add	r10, r10, #4        	// add 4 (r10 = line length offset)
+	ubfx	r4, r12, #3, #10	// r4 = maximum way number (right aligned)
+	clz	r5, r4            	// r5 = the bit position of the way size increment
+	mov	r9, r4			// r9 working copy of the aligned max way number
+
+loop2:
+	ubfx	r7, r12, #13, #15	// r7 = max set number (right aligned)
+
+loop3:
+	orr	r0, r1, r9, LSL r5	// factor in the way number and cache level into r0
+	orr	r0, r0, r7, LSL r10	// factor in the set number
+
+	blx	r6
+	subs	r7, r7, #1              // decrement the set number
+	bge	loop3
+	subs	r9, r9, #1              // decrement the way number
+	bge	loop2
+level_done:
+	add	r1, r1, #2		// increment the cache number
+	cmp	r3, r1
+	dsb	sy			// ensure completion of previous cache maintenance instruction
+	bgt	loop1
+
+	mov	r6, #0
+	stcopr	r6, CSSELR		//select cache level 0 in csselr
+	dsb	sy
+	isb
+	pop	{r4-r12,pc}
+
+dcsw_loop_table:
+	stcopr	r0, DCISW
+	bx	lr
+	stcopr	r0, DCCISW
+	bx	lr
+	stcopr	r0, DCCSW
+	bx	lr
+
+endfunc do_dcsw_op
+
+	/* ---------------------------------------------------------------
+	 * Data cache operations by set/way till PoU.
+	 *
+	 * The function requires :
+	 * r0: The operation type (DC_OP_ISW, DC_OP_CISW, DC_OP_CSW),
+	 * as defined in arch.h
+	 * ---------------------------------------------------------------
+	 */
+func dcsw_op_louis
+	dcsw_op #LOUIS_SHIFT, #CLIDR_FIELD_WIDTH, #LEVEL_SHIFT
+endfunc	dcsw_op_louis
+
+	/* ---------------------------------------------------------------
+	 * Data cache operations by set/way till PoC.
+	 *
+	 * The function requires :
+	 * r0: The operation type (DC_OP_ISW, DC_OP_CISW, DC_OP_CSW),
+	 * as defined in arch.h
+	 * ---------------------------------------------------------------
+	 */
+func dcsw_op_all
+	dcsw_op #LOC_SHIFT, #CLIDR_FIELD_WIDTH, #LEVEL_SHIFT
+endfunc	dcsw_op_all
+
+
+	/* ---------------------------------------------------------------
+	 *  Helper macro for data cache operations by set/way for the
+	 *  level specified
+	 * ---------------------------------------------------------------
+	 */
+	.macro	dcsw_op_level level
+	ldcopr	r2, CLIDR
+	mov	r3, \level
+	sub	r1, r3, #2
+	b	do_dcsw_op
+	.endm
+
+	/* ---------------------------------------------------------------
+	 * Data cache operations by set/way for level 1 cache
+	 *
+	 * The main function, do_dcsw_op requires:
+	 * r0: The operation type (DC_OP_ISW, DC_OP_CISW, DC_OP_CSW),
+	 * as defined in arch.h
+	 * ---------------------------------------------------------------
+	 */
+func dcsw_op_level1
+	dcsw_op_level #(1 << LEVEL_SHIFT)
+endfunc dcsw_op_level1
+
+	/* ---------------------------------------------------------------
+	 * Data cache operations by set/way for level 2 cache
+	 *
+	 * The main function, do_dcsw_op requires:
+	 * r0: The operation type (DC_OP_ISW, DC_OP_CISW, DC_OP_CSW),
+	 * as defined in arch.h
+	 * ---------------------------------------------------------------
+	 */
+func dcsw_op_level2
+	dcsw_op_level #(2 << LEVEL_SHIFT)
+endfunc dcsw_op_level2
+
+	/* ---------------------------------------------------------------
+	 * Data cache operations by set/way for level 3 cache
+	 *
+	 * The main function, do_dcsw_op requires:
+	 * r0: The operation type (DC_OP_ISW, DC_OP_CISW, DC_OP_CSW),
+	 * as defined in arch.h
+	 * ---------------------------------------------------------------
+	 */
+func dcsw_op_level3
+	dcsw_op_level #(3 << LEVEL_SHIFT)
+endfunc dcsw_op_level3
diff --git a/lib/aarch32/misc_helpers.S b/lib/aarch32/misc_helpers.S
new file mode 100644
index 00000000..63ac1a7e
--- /dev/null
+++ b/lib/aarch32/misc_helpers.S
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <assert_macros.S>
+
+	.globl	zeromem
+
+/* -----------------------------------------------------------------------
+ * void zeromem(void *mem, unsigned int length);
+ *
+ * Initialise a memory region to 0.
+ * The memory address and length must be 4-byte aligned.
+ * -----------------------------------------------------------------------
+ */
+func zeromem
+#if ASM_ASSERTION
+	tst	r0, #0x3
+	ASM_ASSERT(eq)
+	tst	r1, #0x3
+	ASM_ASSERT(eq)
+#endif
+	add	r2, r0, r1
+	mov	r1, #0
+z_loop:
+	cmp	r2, r0
+	beq	z_end
+	str	r1, [r0], #4
+	b	z_loop
+z_end:
+	bx	lr
+endfunc zeromem