Re: [RFC] i2c: omap: TEST: do IP reset during probe.

[Alexander Kochetkov]

29 нояб. 2014 г., в 1:13, Tony Lindgren <tony@xxxxxxxxxxx> написал(а):

> Looks like for some time 2430 i2c has not been behaving
> reliably

    commit dd74548ddece4b9d68e5528287a272fa552c81d0 ("i2c: omap:
    resize fifos before each message") dropped check for dev->buf_len.
    As result, data processing loop cause dev->buf overruns for
    devices with 16-bit data register (omap2420 only).
    Found by code review.

I have the patch for that. omap2420 actually broken at all.
But I'm not ready to send it right now.

Part of the patch:

-       while (num_bytes--) {
+       while (num_bytes) {
                w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
                *dev->buf++ = w;
                dev->buf_len--;
+               num_bytes--;
 
                /*
                 * Data reg in 2430, omap3 and
                 * omap4 is 8 bit wide
                 */
                if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) {
-                       *dev->buf++ = w >> 8;
-                       dev->buf_len--;
+                       if (num_bytes) {
+                               *dev->buf++ = w >> 8;
+                               dev->buf_len--;
+                               num_bytes--;
+                       }
                }
        }



-       while (num_bytes--) {
+       while (num_bytes) {
                if (dev->errata & I2C_OMAP_ERRATA_I462) {
                        int ret;
 
@@ -931,14 +947,18 @@ static int omap_i2c_transmit_data(struct omap_i2c_dev *dev, u8 num_bytes,
 
                w = *dev->buf++;
                dev->buf_len--;
+               num_bytes--;
 
                /*
                 * Data reg in 2430, omap3 and
                 * omap4 is 8 bit wide
                 */
                if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) {
-                       w |= *dev->buf++ << 8;
-                       dev->buf_len--;
+                       if (num_bytes) {
+                               w |= *dev->buf++ << 8;
+                               dev->buf_len--;
+                               num_bytes--;
+                       }
                }

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