[PATCH] ARM: stm32: Add additional ID register check for KSZ8851 presence

[Patrice CHOTARD]

Hi Marek

On 5/3/21 1:31 PM, Marek Vasut wrote:
> Currently the code sets eth1addr only if /ethernet1 alias exists in DT,
> the node pointed to by the alias has "micrel,ks8851-mll" compatible
> string, and the KSZ8851 CCR register read indicates programmed EEPROM
> is not connected.
> 
> This is not sufficient to detect cases where the DT still contains the
> KSZ8851 nodes, but the chip itself is not present. Extend the detection
> to handle these cases.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Patrice Chotard <patrice.chotard at foss.st.com>
> Cc: Patrick Delaunay <patrick.delaunay at foss.st.com>
> ---
>  board/dhelectronics/dh_stm32mp1/board.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/board/dhelectronics/dh_stm32mp1/board.c b/board/dhelectronics/dh_stm32mp1/board.c
> index 49b12c4c042..ac1af718d4a 100644
> --- a/board/dhelectronics/dh_stm32mp1/board.c
> +++ b/board/dhelectronics/dh_stm32mp1/board.c
> @@ -86,6 +86,8 @@ DECLARE_GLOBAL_DATA_PTR;
>  #define KS_CCR_EEPROM	BIT(9)
>  #define KS_BE0		BIT(12)
>  #define KS_BE1		BIT(13)
> +#define KS_CIDER	0xC0
> +#define CIDER_ID	0x8870
>  
>  int setup_mac_address(void)
>  {
> @@ -123,11 +125,18 @@ int setup_mac_address(void)
>  	 * is present. If EEPROM is present, it must contain valid
>  	 * MAC address.
>  	 */
> -	u32 reg, ccr;
> +	u32 reg, cider, ccr;
>  	reg = fdt_get_base_address(gd->fdt_blob, off);
>  	if (!reg)
>  		goto out_set_ethaddr;
>  
> +	writew(KS_BE0 | KS_BE1 | KS_CIDER, reg + 2);
> +	cider = readw(reg);
> +	if ((cider & 0xfff0) != CIDER_ID) {
> +		skip_eth1 = true;
> +		goto out_set_ethaddr;
> +	}
> +
>  	writew(KS_BE0 | KS_BE1 | KS_CCR, reg + 2);
>  	ccr = readw(reg);
>  	if (ccr & KS_CCR_EEPROM) {
> 

Reviewed-by: Patrice Chotard <patrice.chotard at foss.st.com>

Thanks
Patrice