pbank.c

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#include <string.h>

#include <hipc/atomic.h>
#include <hipc/pbank.h>

void hipcPbankInit(struct HIPC_pbank *const bank_p,
                   void *const buf_p, const size_t page_size)
{
    bank_p->stat = HIPC_PBANK_STAT_GROUND;
    bank_p->page_size = page_size;
    bank_p->page_ro_p = buf_p;
    bank_p->page_rw_p = (unsigned char *) buf_p + page_size;
    memcpy(bank_p->page_rw_p, buf_p, page_size);
    HIPC_MEM_BARRIER;

    return;
}

size_t hipcPbankGetPageSize(struct HIPC_pbank * const bank_p)
{
    return bank_p->page_size;
}

const void *hipcPbankGetReadOnlyPage(struct HIPC_pbank *const bank_p)
{
    return bank_p->page_ro_p;
}

void *hipcPbankGetWritablePage(struct HIPC_pbank *const bank_p)
{
    return bank_p->page_rw_p;
}

enum HIPC_pbank_stat hipcPbankGetStat(struct HIPC_pbank *const bank_p)
{
    return bank_p->stat;
}

enum HIPC_errno hipcPbankSwitchRequest(struct HIPC_pbank *const bank_p)
{
    if (HIPC_PBANK_STAT_GROUND != bank_p->stat) {
        return HIPC_ERR_S_PBANK_STAT_MISMATCH;
    }

    HIPC_MEM_BARRIER;
    bank_p->stat = HIPC_PBANK_STAT_REQUESTED;

    return HIPC_SUCCESS;
}

int hipcPbankSwitchAccept(struct HIPC_pbank *const bank_p)
{
    void *tmp_p;

    if (HIPC_PBANK_STAT_REQUESTED != bank_p->stat) {
        return 0;
    } else {
        /* swap page_ro_p for page_rw_p */
        tmp_p = bank_p->page_ro_p;
        bank_p->page_ro_p = bank_p->page_rw_p;
        bank_p->page_rw_p = tmp_p;

        HIPC_MEM_BARRIER;
        bank_p->stat = HIPC_PBANK_STAT_ACCEPTED;

        return 1;
    }
}

enum HIPC_errno hipcPbankSwitchComplete(struct HIPC_pbank *const bank_p)
{
    if (HIPC_PBANK_STAT_ACCEPTED != bank_p->stat) {
        return HIPC_ERR_S_PBANK_STAT_MISMATCH;
    }

    memcpy(bank_p->page_rw_p, bank_p->page_ro_p, bank_p->page_size);
    HIPC_MEM_BARRIER;
    bank_p->stat = HIPC_PBANK_STAT_GROUND;

    return HIPC_SUCCESS;
}

enum HIPC_errno hipcPbankSwitchReqWaitCmpl(struct HIPC_pbank *const bank_p)
{
    enum HIPC_errno retval;

    retval = hipcPbankSwitchRequest(bank_p);
    if (HIPC_SUCCESS != retval) {
        return retval;
    }

    while (HIPC_PBANK_STAT_REQUESTED == hipcPbankGetStat(bank_p)) {
        ;                       /* nothing to do */
    }

    return hipcPbankSwitchComplete(bank_p);
}