MDIO clock needs to be initialized in u-boot code for SoCs having FMAN-v3(v3H or v3L) controller due to below reasons
-On SoCs that have FMAN-v3H like B4860, default value of MDIO_CLK_DIV bits in mdio_stat(mdio_cfg) register generates mdio clock too high (much higher than 2.5MHz), violating the IEEE specs. -On SOCs that have FMAN-v3L like T1040, default value of MDIO_CLK_DIV bits is zero, so MDIO clock is disabled.
So, for proper functioninig of MDIO, MDIO_CLK_DIV bits needs to be properly initialized. Also this type of initialization is generally done in PBI(pre-bootloader) phase using rcw.But for chips like T1040 which support deep-sleep, such type of initialization cannot be done in PBI phase due to the limitation that during deep-sleep resume, FMAN (MDIO) registers are not accessible in PBI phase. So, mdio clock initailization must be done as part of u-boot.
This initialization code is implemented in memac_phy.c which gets compiled only for SoCs having FMANv3, so no extra compilation flag is required.
Signed-off-by: Priyanka Jain Priyanka.Jain@freescale.com Change-Id: I1d2240fe424ecda55a9028190108a2677228ade5 Reviewed-on: http://git.am.freescale.net:8181/9839 Tested-by: Review Code-CDREVIEW CDREVIEW@freescale.com Reviewed-by: Yusong Sun yorksun@freescale.com --- drivers/net/fm/memac_phy.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/net/fm/memac_phy.c b/drivers/net/fm/memac_phy.c index 140e59b..2f4bc11 100644 --- a/drivers/net/fm/memac_phy.c +++ b/drivers/net/fm/memac_phy.c @@ -133,5 +133,17 @@ int fm_memac_mdio_init(bd_t *bis, struct memac_mdio_info *info)
bus->priv = info->regs;
+ /* + * On some platforms like B4860, default value of MDIO_CLK_DIV bits + * in mdio_stat(mdio_cfg) register generates MDIO clock too high + * (much higher than 2.5MHz), violating the IEEE specs. + * On other platforms like T1040, default value of MDIO_CLK_DIV bits + * is zero, so MDIO clock is disabled. + * So, for proper functioning of MDIO, MDIO_CLK_DIV bits needs to + * be properly initialized. + */ + setbits_be32(&((struct memac_mdio_controller *)info->regs)->mdio_stat, + MDIO_STAT_CLKDIV(258)); + return mdio_register(bus); }