[U-Boot,v4] arm: socfpga: mailbox: Fix off-by-one error on command length checking

A mailbox command contains 1-u32 header + arguments. The "len" variable
only contains the length of the arguments, but not the 1-u32 header.
Include the length of header when checking the ring buffer space to
prevent off-by-one error.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
---
v3->v4:
- Change DWORD to u32 in commit message
- Add note len is in u32 unit in code

v2->v3:
- Update commit description.
---
 arch/arm/mach-socfpga/mailbox_s10.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Ley Foon Tan <ley.foon.tan@intel.com> schrieb am Mi., 24. Apr. 2019, 07:21:

> A mailbox command contains 1-u32 header + arguments. The "len" variable
> only contains the length of the arguments, but not the 1-u32 header.
> Include the length of header when checking the ring buffer space to
> prevent off-by-one error.
>
> Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
> Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
>

Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

---
> v3->v4:
> - Change DWORD to u32 in commit message
> - Add note len is in u32 unit in code
>
> v2->v3:
> - Update commit description.
> ---
>  arch/arm/mach-socfpga/mailbox_s10.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-socfpga/mailbox_s10.c
> b/arch/arm/mach-socfpga/mailbox_s10.c
> index 3c33223936..4498ab55df 100644
> --- a/arch/arm/mach-socfpga/mailbox_s10.c
> +++ b/arch/arm/mach-socfpga/mailbox_s10.c
> @@ -55,11 +55,11 @@ static __always_inline int
> mbox_fill_cmd_circular_buff(u32 header, u32 len,
>         cout = MBOX_READL(MBOX_COUT) % MBOX_CMD_BUFFER_SIZE;
>
>         /* if command buffer is full or not enough free space
> -        * to fit the data
> +        * to fit the data. Note, len is in u32 unit.
>          */
>         if (((cin + 1) % MBOX_CMD_BUFFER_SIZE) == cout ||
>             ((MBOX_CMD_BUFFER_SIZE - cin + cout - 1) %
> -            MBOX_CMD_BUFFER_SIZE) < len)
> +            MBOX_CMD_BUFFER_SIZE) < (len + 1))
>                 return -ENOMEM;
>
>         /* write header to circular buffer */
> --
> 2.19.0
>
>

On 4/24/19 7:21 AM, Ley Foon Tan wrote:
> A mailbox command contains 1-u32 header + arguments. The "len" variable
> only contains the length of the arguments, but not the 1-u32 header.
> Include the length of header when checking the ring buffer space to
> prevent off-by-one error.
> 
> Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
> Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
> ---
> v3->v4:
> - Change DWORD to u32 in commit message
> - Add note len is in u32 unit in code
> 
> v2->v3:
> - Update commit description.
> ---
>  arch/arm/mach-socfpga/mailbox_s10.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-socfpga/mailbox_s10.c b/arch/arm/mach-socfpga/mailbox_s10.c
> index 3c33223936..4498ab55df 100644
> --- a/arch/arm/mach-socfpga/mailbox_s10.c
> +++ b/arch/arm/mach-socfpga/mailbox_s10.c
> @@ -55,11 +55,11 @@ static __always_inline int mbox_fill_cmd_circular_buff(u32 header, u32 len,
>  	cout = MBOX_READL(MBOX_COUT) % MBOX_CMD_BUFFER_SIZE;
>  
>  	/* if command buffer is full or not enough free space
> -	 * to fit the data
> +	 * to fit the data. Note, len is in u32 unit.
>  	 */
>  	if (((cin + 1) % MBOX_CMD_BUFFER_SIZE) == cout ||
>  	    ((MBOX_CMD_BUFFER_SIZE - cin + cout - 1) %
> -	     MBOX_CMD_BUFFER_SIZE) < len)
> +	     MBOX_CMD_BUFFER_SIZE) < (len + 1))
>  		return -ENOMEM;
>  
>  	/* write header to circular buffer */
> 

Applied, thanks.