Hi Peppe,
On Mon, Dec 9, 2013 at 3:14 PM, Giuseppe CAVALLARO
<peppe.cavallaro@xxxxxx> wrote:
> Hello Chen-Yu
>
>
> On 12/6/2013 6:29 PM, Chen-Yu Tsai wrote:
>>
>> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
>> ---
>>
>> Guiseppe previously stated that the "stmmaceth" clock is the
>> main clock that drives the IP. The stmmac driver does not
>> enable this clock during the probe phase. When the driver is
>> built in to the kernel, this is fine because the clock maybe
>> on by default, or the boot loader had enabled it.
>>
>> If stmmac is built as a module, when the module is loaded,
>> the clock may be found unused and disabled by the kernel.
>
>
> the clk_prepare_enable is then called in the open.
> Is it not working for you?
> Do you mean that the stmmac_hw_init fails if you do not move
> the clk_get and clk_prepare_enable on top of the stmmac_dvr_probe?
>
Exactly. The clock needs to be enabled prior to stmmac_dvr_probe.
Otherwise, stmmac_mdio_register will fail to find a usable PHY.
The DWMAC core I am working with does not support chip ID or
HW capability flags. I suspect those would fail, too.
Disabling the clock at the end of stmmac_dvr_probe is to make
sure it plays nice with existing power management callbacks.
Chen-Yu
>>
>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 24
>> +++++++++++++----------
>> 1 file changed, 14 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> index 8d4ccd3..7da71ed 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> @@ -2688,10 +2688,17 @@ struct stmmac_priv *stmmac_dvr_probe(struct device
>> *device,
>> if ((phyaddr >= 0) && (phyaddr <= 31))
>> priv->plat->phy_addr = phyaddr;
>>
>> + priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
>> + if (IS_ERR(priv->stmmac_clk)) {
>> + pr_warn("%s: warning: cannot get CSR clock\n", __func__);
>> + goto error_clk_get;
>> + }
>> + clk_prepare_enable(priv->stmmac_clk);
>> +
>> /* Init MAC and get the capabilities */
>> ret = stmmac_hw_init(priv);
>> if (ret)
>> - goto error_free_netdev;
>> + goto error_hw_init;
>>
>> ndev->netdev_ops = &stmmac_netdev_ops;
>>
>> @@ -2729,12 +2736,6 @@ struct stmmac_priv *stmmac_dvr_probe(struct device
>> *device,
>> goto error_netdev_register;
>> }
>>
>> - priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
>> - if (IS_ERR(priv->stmmac_clk)) {
>> - pr_warn("%s: warning: cannot get CSR clock\n", __func__);
>> - goto error_clk_get;
>> - }
>> -
>> /* If a specific clk_csr value is passed from the platform
>> * this means that the CSR Clock Range selection cannot be
>> * changed at run-time and it is fixed. Viceversa the driver'll
>> try to
>> @@ -2759,15 +2760,18 @@ struct stmmac_priv *stmmac_dvr_probe(struct device
>> *device,
>> }
>> }
>>
>> + clk_disable_unprepare(priv->stmmac_clk);
>> +
>> return priv;
>>
>> error_mdio_register:
>> - clk_put(priv->stmmac_clk);
>> -error_clk_get:
>> unregister_netdev(ndev);
>> error_netdev_register:
>> netif_napi_del(&priv->napi);
>> -error_free_netdev:
>> +error_hw_init:
>> + clk_disable_unprepare(priv->stmmac_clk);
>> + clk_put(priv->stmmac_clk);
>> +error_clk_get:
>> free_netdev(ndev);
>>
>> return NULL;
>>
>
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