[v2] fix bugs reported by Clang Static Analyzer

[Qemu-devel] [PATCH for 2.10 v2 20/20] i2c/exynos4210: fix write to I2CADD register, bit 0 is not mapped

Posted by Philippe Mathieu-Daudé 8 years, 6 months ago

From the Exynos4210 User Manual [1]:

14.4.1.3 I2CADDn (MULTI-MASTER I2C-Bus Address Register)
  [7-1] slave address, latched from the I2C-bus.
  bit [0] is not mapped.

[1]: Exynos_4_Dual_45nm_User_Manaul_Public_REV1.00-0.pdf

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/i2c/exynos4210_i2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/i2c/exynos4210_i2c.c b/hw/i2c/exynos4210_i2c.c
index c96fa7d7be..e6a9ca8f03 100644
--- a/hw/i2c/exynos4210_i2c.c
+++ b/hw/i2c/exynos4210_i2c.c
@@ -243,7 +243,7 @@ static void exynos4210_i2c_write(void *opaque, hwaddr offset,
         break;
     case I2CADD_ADDR:
         if ((s->i2cstat & I2CSTAT_OUTPUT_EN) == 0) {
-            s->i2cadd = v;
+            s->i2cadd = v & ~1;
         }
         break;
     case I2CDS_ADDR:
-- 
2.13.3

Re: [Qemu-devel] [PATCH for 2.10 v2 20/20] i2c/exynos4210: fix write to I2CADD register, bit 0 is not mapped

Posted by Michael Tokarev 8 years, 6 months ago

27.07.2017 05:42, Philippe Mathieu-Daudé wrote:
> From the Exynos4210 User Manual [1]:
> 
> 14.4.1.3 I2CADDn (MULTI-MASTER I2C-Bus Address Register)
>   [7-1] slave address, latched from the I2C-bus.
>   bit [0] is not mapped.
> 
> [1]: Exynos_4_Dual_45nm_User_Manaul_Public_REV1.00-0.pdf

Okay, so what happens when one writes to bit0?

> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  hw/i2c/exynos4210_i2c.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/i2c/exynos4210_i2c.c b/hw/i2c/exynos4210_i2c.c
> index c96fa7d7be..e6a9ca8f03 100644
> --- a/hw/i2c/exynos4210_i2c.c
> +++ b/hw/i2c/exynos4210_i2c.c
> @@ -243,7 +243,7 @@ static void exynos4210_i2c_write(void *opaque, hwaddr offset,
>          break;
>      case I2CADD_ADDR:
>          if ((s->i2cstat & I2CSTAT_OUTPUT_EN) == 0) {
> -            s->i2cadd = v;
> +            s->i2cadd = v & ~1;

Maybe a comment is a good idea here, saying that bit0 is unmapped.

Thanks,

/mjt