omap_i2c.c: Support byte reads to registers

Added support for the byte read of the omap i2c system.
Handling is similar to the way i2c_write and i2c_writeb work.

1 files changed, 56 insertions, 1 deletions

diff --git a/hw/i2c/omap_i2c.c b/hw/i2c/omap_i2c.c
index bff069653..0bd7d853a 100644
--- a/hw/i2c/omap_i2c.c
+++ b/hw/i2c/omap_i2c.c
@@ -330,6 +330,61 @@ static uint32_t omap_i2c_read(void *opaque, hwaddr addr)
     return 0;
 }
 
+static uint32_t omap_i2c_readb(void *opaque, hwaddr addr)
+{
+    OMAPI2CState *s = opaque;
+    int offset = addr & OMAP_MPUI_REG_MASK;
+    uint8_t ret;
+
+    switch (offset) {
+    case 0x1c: /* I2C_DATA */
+        ret = 0;
+        if (s->fifolen) {
+            if (s->revision < OMAP3_INTR_REV) {
+                if (s->control & (1 << 14)) /* BE */
+                    ret = (((uint8_t)s->fifo[s->fifostart]) << 8)
+                        | s->fifo[(s->fifostart + 1) & I2C_FIFO_SIZE_MASK];
+                else
+                    ret = (((uint8_t)s->fifo[(s->fifostart + 1) & I2C_FIFO_SIZE_MASK]) << 8)
+                        | s->fifo[s->fifostart];
+                s->fifostart = (s->fifostart + 2) & I2C_FIFO_SIZE_MASK;
+                if (s->fifolen == 1) {
+                    s->stat |= 1 << 15; /* SBD */
+                    s->fifolen = 0;
+                } else
+                    s->fifolen -= 2;
+                if (!s->fifolen) {
+                    s->stat &= ~(1 << 3); /* RRDY */
+                    s->stat |= 1 << 2;    /* ARDY */
+                }
+            } else {
+                s->stat &= ~(1 << 7); /* AERR */
+                ret = (uint8_t)s->fifo[s->fifostart++];
+                s->fifostart &= I2C_FIFO_SIZE_MASK;
+                if (--s->fifolen) {
+                    if (s->fifolen <= ((s->dma >> 8) & 0x3f)) {
+                        s->stat &= ~(1 << 3); /* RRDY */
+                        s->stat |= 1 << 13;   /* RDR */
+                    }
+                } else {
+                    s->stat &= ~((1 << 3) | (1 << 13)); /* RRDY | RDR */
+                    s->stat |= 1 << 2;                  /* ARDY */
+                }
+            }
+            s->stat &= ~(1 << 11); /* ROVR */
+        } else if (s->revision >= OMAP3_INTR_REV)
+            s->stat |= (1 << 7); /* AERR */
+        omap_i2c_fifo_run(s);
+        omap_i2c_interrupts_update(s);
+        return ret;
+    default:
+        break;
+    }
+
+    OMAP_BAD_REG(addr);
+    return 0;
+}
+
 static void omap_i2c_write(void *opaque, hwaddr addr,
                 uint32_t value)
 {
@@ -593,7 +648,7 @@ static void omap_i2c_writeb(void *opaque, hwaddr addr,
 static const MemoryRegionOps omap_i2c_ops = {
     .old_mmio = {
         .read = {
-            omap_badwidth_read16,
+            omap_i2c_readb,
             omap_i2c_read,
             omap_badwidth_read16,
         },