Subject: Re: [PATCH 2/2] net: mvneta: fix usage as a module on RGMII configurations

From: Gregory CLEMENT <[email-masked]>
Date: Wed, 02 Apr 2014 16:15:17 +0200

Hi,

On 26/03/2014 00:25, Thomas Petazzoni wrote:
> Commit 5445eaf309ff ('mvneta: Try to fix mvneta when compiled as
> module') fixed the mvneta driver to make it work properly when loaded
> as a module in SGMII configuration, which was tested successful by the
> author on the Armada XP OpenBlocks AX3, which uses SGMII.
> 
> However, it turns out that the Armada XP GP, which uses RGMII, is
> affected by a similar problem: its SERDES configuration is lost when
> mvneta is loaded as a module, because this configuration is set by the
> bootloader, and then lost because the clock is gated by the clock
> framework until the mvneta driver is loaded again and the clock is
> re-enabled.
> 
> However, it turns out that for the RGMII case, setting the SERDES
> configuration is not sufficient: the PCS enable bit in the
> MVNETA_GMAC_CTRL_2 register must also be set, like in the SGMII
> configuration.
> 
> Therefore, this commit reworks the SGMII/RGMII initialization: the
> only difference between the two now is a different SERDES
> configuration, all the rest is identical.
> 
> In detail, to achieve this, the commit:
> 
>  * Renames MVNETA_SGMII_SERDES_CFG to MVNETA_SERDES_CFG because it is
>    not specific to SGMII, but also used on RGMII configurations.
> 
>  * Adds a MVNETA_RGMII_SERDES_PROTO definition, that must be used as
>    the MVNETA_SERDES_CFG value in RGMII configurations.
> 
>  * Removes the mvneta_gmac_rgmii_set() and mvneta_port_sgmii_config()
>    functions, and instead directly do the SGMII/RGMII configuration in
>    mvneta_port_up(), from where those functions where called. It is
>    worth mentioning that mvneta_gmac_rgmii_set() had an 'enable'
>    parameter that was always passed as '1', so it was pretty useless.
> 
>  * Reworks the mvneta_port_up() function to set the MVNETA_SERDES_CFG
>    register to the appropriate value depending on the RGMII vs. SGMII
>    configuration. It also unconditionally set the PCS_ENABLE bit (was
>    already done for SGMII, but is now also needed for RGMII), and sets
>    the PORT_RGMII bit (which was already done for both SGMII and
>    RGMII).
> 
> This commit was successfully tested with mvneta compiled as a module,
> on both the OpenBlocks AX3 (SGMII configuration) and the Armada XP GP
> (RGMII configuration).

Unfortunately with this patch, mvneta doesn't work anymore on the
Mirabox (Armada 370 based board) on 3.14.I didn't managed to do a
simple ping.

Once I removed this commit then the driver worked again.

Gregory

> 
> Reported-by: Steve McIntyre <[email-masked]>
> Cc: [email-masked] # 3.11.x: 5445eaf309ff mvneta: Try to fix mvneta when compiled as module
> Signed-off-by: Thomas Petazzoni <[email-masked]>
> ---
>  drivers/net/ethernet/marvell/mvneta.c | 41 +++++++----------------------------
>  1 file changed, 8 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index d6b04d0..c9c2faa 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -88,8 +88,9 @@
>  #define      MVNETA_TX_IN_PRGRS                  BIT(1)
>  #define      MVNETA_TX_FIFO_EMPTY                BIT(8)
>  #define MVNETA_RX_MIN_FRAME_SIZE                 0x247c
> -#define MVNETA_SGMII_SERDES_CFG			 0x24A0
> +#define MVNETA_SERDES_CFG			 0x24A0
>  #define      MVNETA_SGMII_SERDES_PROTO		 0x0cc7
> +#define      MVNETA_RGMII_SERDES_PROTO		 0x0667
>  #define MVNETA_TYPE_PRIO                         0x24bc
>  #define      MVNETA_FORCE_UNI                    BIT(21)
>  #define MVNETA_TXQ_CMD_1                         0x24e4
> @@ -710,35 +711,6 @@ static void mvneta_rxq_bm_disable(struct mvneta_port *pp,
>  	mvreg_write(pp, MVNETA_RXQ_CONFIG_REG(rxq->id), val);
>  }
>  
> -
> -
> -/* Sets the RGMII Enable bit (RGMIIEn) in port MAC control register */
> -static void mvneta_gmac_rgmii_set(struct mvneta_port *pp, int enable)
> -{
> -	u32  val;
> -
> -	val = mvreg_read(pp, MVNETA_GMAC_CTRL_2);
> -
> -	if (enable)
> -		val |= MVNETA_GMAC2_PORT_RGMII;
> -	else
> -		val &= ~MVNETA_GMAC2_PORT_RGMII;
> -
> -	mvreg_write(pp, MVNETA_GMAC_CTRL_2, val);
> -}
> -
> -/* Config SGMII port */
> -static void mvneta_port_sgmii_config(struct mvneta_port *pp)
> -{
> -	u32 val;
> -
> -	val = mvreg_read(pp, MVNETA_GMAC_CTRL_2);
> -	val |= MVNETA_GMAC2_PCS_ENABLE;
> -	mvreg_write(pp, MVNETA_GMAC_CTRL_2, val);
> -
> -	mvreg_write(pp, MVNETA_SGMII_SERDES_CFG, MVNETA_SGMII_SERDES_PROTO);
> -}
> -
>  /* Start the Ethernet port RX and TX activity */
>  static void mvneta_port_up(struct mvneta_port *pp)
>  {
> @@ -2756,12 +2728,15 @@ static void mvneta_port_power_up(struct mvneta_port *pp, int phy_mode)
>  	mvreg_write(pp, MVNETA_UNIT_INTR_CAUSE, 0);
>  
>  	if (phy_mode == PHY_INTERFACE_MODE_SGMII)
> -		mvneta_port_sgmii_config(pp);
> +		mvreg_write(pp, MVNETA_SERDES_CFG, MVNETA_SGMII_SERDES_PROTO);
> +	else
> +		mvreg_write(pp, MVNETA_SERDES_CFG, MVNETA_RGMII_SERDES_PROTO);
>  
> -	mvneta_gmac_rgmii_set(pp, 1);
> +	val = mvreg_read(pp, MVNETA_GMAC_CTRL_2);
> +
> +	val |= MVNETA_GMAC2_PCS_ENABLE | MVNETA_GMAC2_PORT_RGMII;
>  
>  	/* Cancel Port Reset */
> -	val = mvreg_read(pp, MVNETA_GMAC_CTRL_2);
>  	val &= ~MVNETA_GMAC2_PORT_RESET;
>  	mvreg_write(pp, MVNETA_GMAC_CTRL_2, val);
>  
> 

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com