path: root/ports/cortex_a7/gnu/example_build/v7.s

// ------------------------------------------------------------
// v7-A Cache and Branch Prediction Maintenance Operations
//
// Copyright (c) 2011-2018 Arm Limited (or its affiliates). All rights reserved.
// Use, modification and redistribution of this file is subject to your possession of a
// valid End User License Agreement for the Arm Product of which these examples are part of
// and your compliance with all applicable terms and conditions of such licence agreement.
// ------------------------------------------------------------

    .arm
// ------------------------------------------------------------
// Interrupt enable/disable
// ------------------------------------------------------------

  // Could use intrinsic instead of these

    .global enableInterrupts
    .type   enableInterrupts,function
  // void enableInterrupts(void)//
enableInterrupts:
    CPSIE   i
    BX      lr


    .global disableInterrupts
    .type   disableInterrupts,function
  // void disableInterrupts(void)//
disableInterrupts:
    CPSID   i
    BX      lr


// ------------------------------------------------------------
// Cache Maintenance
// ------------------------------------------------------------

    .global enableCaches
    .type   enableCaches,function
  // void enableCaches(void)//
enableCaches:
    MRC     p15, 0, r0, c1, c0, 0   // Read System Control Register
    ORR     r0, r0, #(1 << 2)       // Set C bit
    ORR     r0, r0, #(1 << 12)      // Set I bit
    MCR     p15, 0, r0, c1, c0, 0   // Write System Control Register
    ISB
    BX      lr



    .global disableCaches
    .type   disableCaches,function
  // void disableCaches(void)
disableCaches:
    MRC     p15, 0, r0, c1, c0, 0   // Read System Control Register
    BIC     r0, r0, #(1 << 2)       // Clear C bit
    BIC     r0, r0, #(1 << 12)      // Clear I bit
    MCR     p15, 0, r0, c1, c0, 0   // Write System Control Register
    ISB
    BX      lr



    .global cleanDCache
    .type   cleanDCache,function
  // void cleanDCache(void)//
cleanDCache:
    PUSH    {r4-r12}

    //
    // Based on code example given in section 11.2.4 of Armv7-A/R Architecture Reference Manual (DDI 0406B)
    //

    MRC     p15, 1, r0, c0, c0, 1     // Read CLIDR
    ANDS    r3, r0, #0x7000000
    MOV     r3, r3, LSR #23           // Cache level value (naturally aligned)
    BEQ     clean_dcache_finished
    MOV     r10, #0

clean_dcache_loop1:
    ADD     r2, r10, r10, LSR #1      // Work out 3xcachelevel
    MOV     r1, r0, LSR r2            // bottom 3 bits are the Cache type for this level
    AND     r1, r1, #7                // get those 3 bits alone
    CMP     r1, #2
    BLT     clean_dcache_skip         // no cache or only instruction cache at this level
    MCR     p15, 2, r10, c0, c0, 0    // write the Cache Size selection register
    ISB                               // ISB to sync the change to the CacheSizeID reg
    MRC     p15, 1, r1, c0, c0, 0     // reads current Cache Size ID register
    AND     r2, r1, #7                // extract the line length field
    ADD     r2, r2, #4                // add 4 for the line length offset (log2 16 bytes)
    LDR     r4, =0x3FF
    ANDS    r4, r4, r1, LSR #3        // R4 is the max number on the way size (right aligned)
    CLZ     r5, r4                    // R5 is the bit position of the way size increment
    LDR     r7, =0x00007FFF
    ANDS    r7, r7, r1, LSR #13       // R7 is the max number of the index size (right aligned)

clean_dcache_loop2:
    MOV     r9, R4                    // R9 working copy of the max way size (right aligned)

clean_dcache_loop3:
    ORR     r11, r10, r9, LSL r5      // factor in the way number and cache number into R11
    ORR     r11, r11, r7, LSL r2      // factor in the index number
    MCR     p15, 0, r11, c7, c10, 2   // DCCSW - clean by set/way
    SUBS    r9, r9, #1                // decrement the way number
    BGE     clean_dcache_loop3
    SUBS    r7, r7, #1                // decrement the index
    BGE     clean_dcache_loop2

clean_dcache_skip:
    ADD     r10, r10, #2              // increment the cache number
    CMP     r3, r10
    BGT     clean_dcache_loop1

clean_dcache_finished:
    POP     {r4-r12}

    BX      lr


    .global cleanInvalidateDCache
    .type   cleanInvalidateDCache,function
  // void cleanInvalidateDCache(void)//
cleanInvalidateDCache:
    PUSH    {r4-r12}

    //
    // Based on code example given in section 11.2.4 of Armv7-A/R Architecture Reference Manual (DDI 0406B)
    //

    MRC     p15, 1, r0, c0, c0, 1     // Read CLIDR
    ANDS    r3, r0, #0x7000000
    MOV     r3, r3, LSR #23           // Cache level value (naturally aligned)
    BEQ     clean_invalidate_dcache_finished
    MOV     r10, #0

clean_invalidate_dcache_loop1:
    ADD     r2, r10, r10, LSR #1      // Work out 3xcachelevel
    MOV     r1, r0, LSR r2            // bottom 3 bits are the Cache type for this level
    AND     r1, r1, #7                // get those 3 bits alone
    CMP     r1, #2
    BLT     clean_invalidate_dcache_skip // no cache or only instruction cache at this level
    MCR     p15, 2, r10, c0, c0, 0    // write the Cache Size selection register
    ISB                               // ISB to sync the change to the CacheSizeID reg
    MRC     p15, 1, r1, c0, c0, 0     // reads current Cache Size ID register
    AND     r2, r1, #7                // extract the line length field
    ADD     r2, r2, #4                // add 4 for the line length offset (log2 16 bytes)
    LDR     r4, =0x3FF
    ANDS    r4, r4, r1, LSR #3        // R4 is the max number on the way size (right aligned)
    CLZ     r5, r4                    // R5 is the bit position of the way size increment
    LDR     r7, =0x00007FFF
    ANDS    r7, r7, r1, LSR #13       // R7 is the max number of the index size (right aligned)

clean_invalidate_dcache_loop2:
    MOV     r9, R4                    // R9 working copy of the max way size (right aligned)

clean_invalidate_dcache_loop3:
    ORR     r11, r10, r9, LSL r5      // factor in the way number and cache number into R11
    ORR     r11, r11, r7, LSL r2      // factor in the index number
    MCR     p15, 0, r11, c7, c14, 2   // DCCISW - clean and invalidate by set/way
    SUBS    r9, r9, #1                // decrement the way number
    BGE     clean_invalidate_dcache_loop3
    SUBS    r7, r7, #1                // decrement the index
    BGE     clean_invalidate_dcache_loop2

clean_invalidate_dcache_skip:
    ADD     r10, r10, #2              // increment the cache number
    CMP     r3, r10
    BGT     clean_invalidate_dcache_loop1

clean_invalidate_dcache_finished:
    POP     {r4-r12}

    BX      lr



    .global invalidateCaches
    .type   invalidateCaches,function
  // void invalidateCaches(void)//
invalidateCaches:
    PUSH    {r4-r12}

    //
    // Based on code example given in section B2.2.4/11.2.4 of Armv7-A/R Architecture Reference Manual (DDI 0406B)
    //

    MOV     r0, #0
    MCR     p15, 0, r0, c7, c5, 0     // ICIALLU - Invalidate entire I Cache, and flushes branch target cache

    MRC     p15, 1, r0, c0, c0, 1     // Read CLIDR
    ANDS    r3, r0, #0x7000000
    MOV     r3, r3, LSR #23           // Cache level value (naturally aligned)
    BEQ     invalidate_caches_finished
    MOV     r10, #0

invalidate_caches_loop1:
    ADD     r2, r10, r10, LSR #1      // Work out 3xcachelevel
    MOV     r1, r0, LSR r2            // bottom 3 bits are the Cache type for this level
    AND     r1, r1, #7                // get those 3 bits alone
    CMP     r1, #2
    BLT     invalidate_caches_skip    // no cache or only instruction cache at this level
    MCR     p15, 2, r10, c0, c0, 0    // write the Cache Size selection register
    ISB                               // ISB to sync the change to the CacheSizeID reg
    MRC     p15, 1, r1, c0, c0, 0     // reads current Cache Size ID register
    AND     r2, r1, #7                // extract the line length field
    ADD     r2, r2, #4                // add 4 for the line length offset (log2 16 bytes)
    LDR     r4, =0x3FF
    ANDS    r4, r4, r1, LSR #3        // R4 is the max number on the way size (right aligned)
    CLZ     r5, r4                    // R5 is the bit position of the way size increment
    LDR     r7, =0x00007FFF
    ANDS    r7, r7, r1, LSR #13       // R7 is the max number of the index size (right aligned)

invalidate_caches_loop2:
    MOV     r9, R4                    // R9 working copy of the max way size (right aligned)

invalidate_caches_loop3:
    ORR     r11, r10, r9, LSL r5      // factor in the way number and cache number into R11
    ORR     r11, r11, r7, LSL r2      // factor in the index number
    MCR     p15, 0, r11, c7, c6, 2    // DCISW - invalidate by set/way
    SUBS    r9, r9, #1                // decrement the way number
    BGE     invalidate_caches_loop3
    SUBS    r7, r7, #1                // decrement the index
    BGE     invalidate_caches_loop2

invalidate_caches_skip:
    ADD     r10, r10, #2              // increment the cache number
    CMP     r3, r10
    BGT     invalidate_caches_loop1

invalidate_caches_finished:
    POP     {r4-r12}
    BX      lr



    .global invalidateCaches_IS
    .type   invalidateCaches_IS,function
  // void invalidateCaches_IS(void)//
invalidateCaches_IS:
    PUSH    {r4-r12}

    MOV     r0, #0
    MCR     p15, 0, r0, c7, c1, 0     // ICIALLUIS - Invalidate entire I Cache inner shareable

    MRC     p15, 1, r0, c0, c0, 1     // Read CLIDR
    ANDS    r3, r0, #0x7000000
    MOV     r3, r3, LSR #23           // Cache level value (naturally aligned)
    BEQ     invalidate_caches_is_finished
    MOV     r10, #0

invalidate_caches_is_loop1:
    ADD     r2, r10, r10, LSR #1      // Work out 3xcachelevel
    MOV     r1, r0, LSR r2            // bottom 3 bits are the Cache type for this level
    AND     r1, r1, #7                // get those 3 bits alone
    CMP     r1, #2
    BLT     invalidate_caches_is_skip // no cache or only instruction cache at this level
    MCR     p15, 2, r10, c0, c0, 0    // write the Cache Size selection register
    ISB                               // ISB to sync the change to the CacheSizeID reg
    MRC     p15, 1, r1, c0, c0, 0     // reads current Cache Size ID register
    AND     r2, r1, #7                // extract the line length field
    ADD     r2, r2, #4                // add 4 for the line length offset (log2 16 bytes)
    LDR     r4, =0x3FF
    ANDS    r4, r4, r1, LSR #3        // R4 is the max number on the way size (right aligned)
    CLZ     r5, r4                    // R5 is the bit position of the way size increment
    LDR     r7, =0x00007FFF
    ANDS    r7, r7, r1, LSR #13       // R7 is the max number of the index size (right aligned)

invalidate_caches_is_loop2:
    MOV     r9, R4                    // R9 working copy of the max way size (right aligned)

invalidate_caches_is_loop3:
    ORR     r11, r10, r9, LSL r5      // factor in the way number and cache number into R11
    ORR     r11, r11, r7, LSL r2      // factor in the index number
    MCR     p15, 0, r11, c7, c6, 2    // DCISW - clean by set/way
    SUBS    r9, r9, #1                // decrement the way number
    BGE     invalidate_caches_is_loop3
    SUBS    r7, r7, #1                // decrement the index
    BGE     invalidate_caches_is_loop2

invalidate_caches_is_skip:
    ADD     r10, r10, #2              // increment the cache number
    CMP     r3, r10
    BGT     invalidate_caches_is_loop1

invalidate_caches_is_finished:
    POP     {r4-r12}
    BX      lr


// ------------------------------------------------------------
// TLB
// ------------------------------------------------------------

    .global invalidateUnifiedTLB
    .type   invalidateUnifiedTLB,function
  // void invalidateUnifiedTLB(void)//
invalidateUnifiedTLB:
    MOV     r0, #0
    MCR     p15, 0, r0, c8, c7, 0                 // TLBIALL - Invalidate entire unified TLB
    BX      lr


    .global invalidateUnifiedTLB_IS
    .type   invalidateUnifiedTLB_IS,function
  // void invalidateUnifiedTLB_IS(void)//
invalidateUnifiedTLB_IS:
    MOV     r0, #1
    MCR     p15, 0, r0, c8, c3, 0                 // TLBIALLIS - Invalidate entire unified TLB Inner Shareable
    BX      lr


// ------------------------------------------------------------
// Branch Prediction
// ------------------------------------------------------------

    .global flushBranchTargetCache
    .type   flushBranchTargetCache,function
  // void flushBranchTargetCache(void)
flushBranchTargetCache:
  MOV     r0, #0
  MCR     p15, 0, r0, c7, c5, 6                 // BPIALL - Invalidate entire branch predictor array
  BX      lr


    .global flushBranchTargetCache_IS
    .type   flushBranchTargetCache_IS,function
  // void flushBranchTargetCache_IS(void)
flushBranchTargetCache_IS:
  MOV     r0, #0
  MCR     p15, 0, r0, c7, c1, 6                 // BPIALLIS - Invalidate entire branch predictor array Inner Shareable
  BX      lr


// ------------------------------------------------------------
// High Vecs
// ------------------------------------------------------------

    .global enableHighVecs
    .type   enableHighVecs,function
  // void enableHighVecs(void)//
enableHighVecs:
  MRC     p15, 0, r0, c1, c0, 0 // Read Control Register
  ORR     r0, r0, #(1 << 13)    // Set the V bit (bit 13)
  MCR     p15, 0, r0, c1, c0, 0 // Write Control Register
  ISB
  BX      lr


    .global disableHighVecs
    .type   disableHighVecs,function
  // void disable_highvecs(void)//
disableHighVecs:
  MRC     p15, 0, r0, c1, c0, 0 // Read Control Register
  BIC     r0, r0, #(1 << 13)    // Clear the V bit (bit 13)
  MCR     p15, 0, r0, c1, c0, 0 // Write Control Register
  ISB
  BX      lr


// ------------------------------------------------------------
// Context ID
// ------------------------------------------------------------

    .global getContextID
    .type   getContextID,function
  // uint32_t getContextIDd(void)//
getContextID:
  MRC     p15, 0, r0, c13, c0, 1 // Read Context ID Register
  BX      lr


    .global setContextID
    .type   setContextID,function
  // void setContextID(uint32_t)//
setContextID:
  MCR     p15, 0, r0, c13, c0, 1 // Write Context ID Register
  BX      lr


// ------------------------------------------------------------
// ID registers
// ------------------------------------------------------------

    .global getMIDR
    .type   getMIDR,function
  // uint32_t getMIDR(void)//
getMIDR:
  MRC     p15, 0, r0, c0, c0, 0 // Read Main ID Register (MIDR)
  BX      lr


    .global getMPIDR
    .type   getMPIDR,function
  // uint32_t getMPIDR(void)//
getMPIDR:
  MRC     p15, 0, r0, c0 ,c0, 5// Read Multiprocessor ID register (MPIDR)
  BX      lr


// ------------------------------------------------------------
// CP15 SMP related
// ------------------------------------------------------------

    .global getBaseAddr
    .type   getBaseAddr,function
  // uint32_t getBaseAddr(void)
  // Returns the value CBAR (base address of the private peripheral memory space)
getBaseAddr:
  MRC     p15, 4, r0, c15, c0, 0  // Read peripheral base address
  BX      lr


// ------------------------------------------------------------

    .global getCPUID
    .type   getCPUID,function
  // uint32_t getCPUID(void)
  // Returns the CPU ID (0 to 3) of the CPU executed on
getCPUID:
  MRC     p15, 0, r0, c0, c0, 5   // Read CPU ID register
  AND     r0, r0, #0x03           // Mask off, leaving the CPU ID field
  BX      lr


// ------------------------------------------------------------

    .global goToSleep
    .type   goToSleep,function
  // void goToSleep(void)
goToSleep:
  DSB                             // Clear all pending data accesses
  WFI                             // Go into standby
  B       goToSleep               // Catch in case of rogue events
  BX      lr


// ------------------------------------------------------------

    .global joinSMP
    .type   joinSMP,function
    // void joinSMP(void)
    // Sets the ACTRL.SMP bit
joinSMP:

    // SMP status is controlled by bit 6 of the CP15 Aux Ctrl Reg

    MRC     p15, 0, r0, c1, c0, 1   // Read ACTLR
    MOV     r1, r0
    ORR     r0, r0, #0x040          // Set bit 6
    CMP     r0, r1
    MCRNE   p15, 0, r0, c1, c0, 1   // Write ACTLR
    ISB

    BX      lr


// ------------------------------------------------------------

    .global leaveSMP
    .type   leaveSMP,function
    // void leaveSMP(void)
    // Clear the ACTRL.SMP bit
leaveSMP:

    // SMP status is controlled by bit 6 of the CP15 Aux Ctrl Reg

    MRC     p15, 0, r0, c1, c0, 1   // Read ACTLR
    BIC     r0, r0, #0x040          // Clear bit 6
    MCR     p15, 0, r0, c1, c0, 1   // Write ACTLR
    ISB

    BX      lr


// ------------------------------------------------------------
// End of v7.s
// ------------------------------------------------------------