HelenOS sources
This source file includes following definitions.
- mbox_write
- mbox_read
- bcm2835_prop_get_memory
- bcm2835_fb_init
- bcm2835_mbox_get_fb_size
#include <mm/km.h>
#include <typedefs.h>
#include <genarch/drivers/bcm2835/mbox.h>
static void mbox_write(bcm2835_mbox_t *mbox, uint8_t chan, uint32_t value)
{
        while (mbox->status & MBOX_STATUS_FULL)
                ;
        mbox->write = MBOX_COMPOSE(chan, value);
}
static uint32_t mbox_read(bcm2835_mbox_t *mbox, uint8_t chan)
{
        uint32_t msg;
        do {
                while (mbox->status & MBOX_STATUS_EMPTY)
                        ;
                msg = mbox->read;
        } while (MBOX_MSG_CHAN(msg) != chan);
        return MBOX_MSG_VALUE(msg);
}
bool bcm2835_prop_get_memory(uint32_t *base, uint32_t *size)
{
        bool ret;
        MBOX_BUFF_ALLOC(req, mbox_getmem_buf_t);
        req->buf_hdr.size = sizeof(mbox_getmem_buf_t);
        req->buf_hdr.code = MBOX_PROP_CODE_REQ;
        req->tag_hdr.tag_id = TAG_GET_ARM_MEMORY;
        req->tag_hdr.buf_size = sizeof(mbox_tag_getmem_resp_t);
        req->tag_hdr.val_len = 0;
        req->zero = 0;
        mbox_write((bcm2835_mbox_t *)BCM2835_MBOX0_ADDR,
            MBOX_CHAN_PROP_A2V, KA2VCA((uint32_t)req));
        mbox_read((bcm2835_mbox_t *)BCM2835_MBOX0_ADDR,
            MBOX_CHAN_PROP_A2V);
        if (req->buf_hdr.code == MBOX_PROP_CODE_RESP_OK) {
                *base = req->data.base;
                *size = req->data.size;
                ret = true;
        } else {
                ret = false;
        }
        return ret;
}
bool bcm2835_fb_init(fb_properties_t *prop, uint32_t width, uint32_t height)
{
        bcm2835_mbox_t *fb_mbox;
        bool ret = false;
        MBOX_BUFF_ALLOC(fb_desc, bcm2835_fb_desc_t);
        fb_mbox = (void *) km_map(BCM2835_MBOX0_ADDR, sizeof(bcm2835_mbox_t),
            KM_NATURAL_ALIGNMENT, PAGE_NOT_CACHEABLE);
        fb_desc->width = width;
        fb_desc->height = height;
        fb_desc->virt_width = fb_desc->width;
        fb_desc->virt_height = fb_desc->height;
        fb_desc->pitch = 0;                     
        fb_desc->bpp = 16;
        fb_desc->x_offset = 0;
        fb_desc->y_offset = 0;
        fb_desc->addr = 0;                      
        fb_desc->size = 0;                      
        mbox_write(fb_mbox, MBOX_CHAN_FB, KA2VCA(fb_desc));
        if (mbox_read(fb_mbox, MBOX_CHAN_FB)) {
                printf("BCM2835 framebuffer initialization failed\n");
                goto out;
        }
        prop->addr = fb_desc->addr;
        prop->offset = 0;
        prop->x = fb_desc->width;
        prop->y = fb_desc->height;
        prop->scan = fb_desc->pitch;
        prop->visual = VISUAL_RGB_5_6_5_LE;
        printf("BCM2835 framebuffer at 0x%08x (%dx%d)\n", prop->addr,
            prop->x, prop->y);
        ret = true;
out:
        km_unmap((uintptr_t)fb_mbox, sizeof(bcm2835_mbox_t));
        return ret;
}
bool bcm2835_mbox_get_fb_size(uint32_t *w, uint32_t *h)
{
        bool r;
        MBOX_BUFF_ALLOC(msg, mbox_getfbsize_buf_t);
        bcm2835_mbox_t *mbox;
        mbox = (void *) km_map(BCM2835_MBOX0_ADDR, sizeof(bcm2835_mbox_t),
            KM_NATURAL_ALIGNMENT, PAGE_NOT_CACHEABLE);
        assert(mbox);
        msg->buf_hdr.size = sizeof(mbox_getfbsize_buf_t);
        msg->buf_hdr.code = MBOX_PROP_CODE_REQ;
        msg->tag_hdr.tag_id = MBOX_TAG_GET_PHYS_W_H;
        msg->tag_hdr.buf_size = sizeof(msg->body);
        msg->tag_hdr.val_len  = 0;
        msg->zero = 0;
        mbox_write(mbox,
            MBOX_CHAN_PROP_A2V, KA2VCA((uint32_t)msg));
        mbox_read(mbox, MBOX_CHAN_PROP_A2V);
        r = msg->buf_hdr.code == MBOX_PROP_CODE_RESP_OK;
        if (r) {
                *h = msg->body.height;
                *w = msg->body.width;
        }
        km_unmap((uintptr_t) mbox, sizeof(bcm2835_mbox_t));
        return r;
}
HelenOS homepage, sources at GitHub