Re: [RFC Patch net-next 03/10] net: dsa: microchip: add common 100/10Mbps selection function

[Vladimir Oltean <olteanv@gmail.com>]

On Tue, Jul 12, 2022 at 09:33:01PM +0530, Arun Ramadoss wrote:
> This patch adds the function for configuring the 100/10Mbps speed
> selection for the ksz switches. KSZ8795 switch uses Global control 4
> register 0x06 bit 4 for choosing 100/10Mpbs. Other switches uses xMII
> control 1 0xN300 for it.
> For KSZ8795, if the bit is set then 10Mbps is chosen and if bit is
> clear then 100Mbps chosen. For all other switches it is other way
> around, if the bit is set then 100Mbps is chosen.
> So, this patch add the generic function for ksz switch to select the
> 100/10Mbps speed selection. While configuring, first it disables the
> gigabit functionality and then configure the respective speed.
> 
> Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
> ---
>  drivers/net/dsa/microchip/ksz9477_reg.h  |  1 -
>  drivers/net/dsa/microchip/ksz_common.c   | 29 ++++++++++++++++++++++++
>  drivers/net/dsa/microchip/ksz_common.h   |  6 +++++
>  drivers/net/dsa/microchip/lan937x_main.c | 14 ++++--------
>  drivers/net/dsa/microchip/lan937x_reg.h  |  1 -
>  5 files changed, 40 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h
> index f23ed4809e47..2649fdf0bae1 100644
> --- a/drivers/net/dsa/microchip/ksz9477_reg.h
> +++ b/drivers/net/dsa/microchip/ksz9477_reg.h
> @@ -1179,7 +1179,6 @@
>  
>  #define PORT_SGMII_SEL			BIT(7)
>  #define PORT_MII_FULL_DUPLEX		BIT(6)
> -#define PORT_MII_100MBIT		BIT(4)
>  #define PORT_GRXC_ENABLE		BIT(0)
>  
>  #define REG_PORT_XMII_CTRL_1		0x0301
> diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
> index 5ebcd87fc531..f41cd2801210 100644
> --- a/drivers/net/dsa/microchip/ksz_common.c
> +++ b/drivers/net/dsa/microchip/ksz_common.c
> @@ -256,6 +256,7 @@ static const u16 ksz8795_regs[] = {
>  	[S_START_CTRL]			= 0x01,
>  	[S_BROADCAST_CTRL]		= 0x06,
>  	[S_MULTICAST_CTRL]		= 0x04,
> +	[P_XMII_CTRL_0]			= 0x06,
>  	[P_XMII_CTRL_1]			= 0x56,
>  };
>  
> @@ -284,6 +285,8 @@ static const u32 ksz8795_masks[] = {
>  static const u8 ksz8795_values[] = {
>  	[P_MII_1GBIT]			= 1,
>  	[P_MII_NOT_1GBIT]		= 0,
> +	[P_MII_100MBIT]			= 0,
> +	[P_MII_10MBIT]			= 1,

Can you namespace P_GMII_1GBIT/P_GMII_NOT_1GBIT separately from
P_MII_100MBIT/P_MII_10MBIT? Otherwise it's not obvious that the first
set writes to regs[P_XMII_CTRL_1] and the other to regs[P_XMII_CTRL_0].

>  };
>  
>  static const u8 ksz8795_shifts[] = {
> @@ -356,6 +359,7 @@ static const u16 ksz9477_regs[] = {
>  	[S_START_CTRL]			= 0x0300,
>  	[S_BROADCAST_CTRL]		= 0x0332,
>  	[S_MULTICAST_CTRL]		= 0x0331,
> +	[P_XMII_CTRL_0]			= 0x0300,
>  	[P_XMII_CTRL_1]			= 0x0301,
>  };
>  
> @@ -371,11 +375,15 @@ static const u8 ksz9477_shifts[] = {
>  static const u8 ksz9477_values[] = {
>  	[P_MII_1GBIT]			= 0,
>  	[P_MII_NOT_1GBIT]		= 1,
> +	[P_MII_100MBIT]			= 1,
> +	[P_MII_10MBIT]			= 0,
>  };
>  
>  static const u8 ksz9893_values[] = {
>  	[P_MII_1GBIT]			= 1,
>  	[P_MII_NOT_1GBIT]		= 0,
> +	[P_MII_100MBIT]			= 1,
> +	[P_MII_10MBIT]			= 0,
>  };
>  
>  static const u32 lan937x_masks[] = {
> @@ -1418,6 +1426,27 @@ void ksz_set_gbit(struct ksz_device *dev, int port, bool gbit)
>  	ksz_pwrite8(dev, port, regs[P_XMII_CTRL_1], data8);
>  }
>  
> +void ksz_set_100_10mbit(struct ksz_device *dev, int port, int speed)
> +{
> +	const u8 *bitval = dev->info->bitval;
> +	const u16 *regs = dev->info->regs;
> +	u8 data8;
> +
> +	ksz_pread8(dev, port, regs[P_XMII_CTRL_0], &data8);
> +
> +	data8 &= ~P_MII_100MBIT_M;
> +
> +	ksz_set_gbit(dev, port, false);
> +
> +	if (speed == SPEED_100)
> +		data8 |= FIELD_PREP(P_MII_100MBIT_M, bitval[P_MII_100MBIT]);
> +	else
> +		data8 |= FIELD_PREP(P_MII_100MBIT_M, bitval[P_MII_10MBIT]);
> +
> +	/* Write the updated value */
> +	ksz_pwrite8(dev, port, regs[P_XMII_CTRL_0], data8);
> +}
> +
>  static void ksz_phylink_mac_link_up(struct dsa_switch *ds, int port,
>  				    unsigned int mode,
>  				    phy_interface_t interface,
> diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
> index a76dfef6309c..f1fa6feca559 100644
> --- a/drivers/net/dsa/microchip/ksz_common.h
> +++ b/drivers/net/dsa/microchip/ksz_common.h
> @@ -172,6 +172,7 @@ enum ksz_regs {
>  	S_START_CTRL,
>  	S_BROADCAST_CTRL,
>  	S_MULTICAST_CTRL,
> +	P_XMII_CTRL_0,
>  	P_XMII_CTRL_1,
>  };
>  
> @@ -215,6 +216,8 @@ enum ksz_shifts {
>  enum ksz_values {
>  	P_MII_1GBIT,
>  	P_MII_NOT_1GBIT,
> +	P_MII_100MBIT,
> +	P_MII_10MBIT,
>  };
>  
>  struct alu_struct {
> @@ -304,6 +307,7 @@ void ksz_r_mib_stats64(struct ksz_device *dev, int port);
>  void ksz_port_stp_state_set(struct dsa_switch *ds, int port, u8 state);
>  bool ksz_get_gbit(struct ksz_device *dev, int port);
>  void ksz_set_gbit(struct ksz_device *dev, int port, bool gbit);
> +void ksz_set_100_10mbit(struct ksz_device *dev, int port, int speed);
>  extern const struct ksz_chip_data ksz_switch_chips[];
>  
>  /* Common register access functions */
> @@ -468,6 +472,8 @@ static inline int is_lan937x(struct ksz_device *dev)
>  #define SW_START			0x01
>  
>  /* xMII configuration */
> +#define P_MII_100MBIT_M			BIT(4)
> +
>  #define P_MII_1GBIT_M			BIT(6)
>  
>  /* Regmap tables generation */
> diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
> index efca96b02e15..37f63110e5bb 100644
> --- a/drivers/net/dsa/microchip/lan937x_main.c
> +++ b/drivers/net/dsa/microchip/lan937x_main.c
> @@ -346,21 +346,18 @@ static void lan937x_config_interface(struct ksz_device *dev, int port,
>  				     int speed, int duplex,
>  				     bool tx_pause, bool rx_pause)
>  {
> -	u8 xmii_ctrl0, xmii_ctrl1;
> +	u8 xmii_ctrl0;
>  
>  	ksz_pread8(dev, port, REG_PORT_XMII_CTRL_0, &xmii_ctrl0);
> -	ksz_pread8(dev, port, REG_PORT_XMII_CTRL_1, &xmii_ctrl1);
>  
> -	xmii_ctrl0 &= ~(PORT_MII_100MBIT | PORT_MII_FULL_DUPLEX |
> -			PORT_MII_TX_FLOW_CTRL | PORT_MII_RX_FLOW_CTRL);
> +	xmii_ctrl0 &= ~(PORT_MII_FULL_DUPLEX | PORT_MII_TX_FLOW_CTRL |
> +			PORT_MII_RX_FLOW_CTRL);
>  
>  	if (speed == SPEED_1000)
>  		ksz_set_gbit(dev, port, true);
> -	else
> -		ksz_set_gbit(dev, port, false);
>  
> -	if (speed == SPEED_100)
> -		xmii_ctrl0 |= PORT_MII_100MBIT;
> +	if (speed == SPEED_100 || speed == SPEED_10)
> +		ksz_set_100_10mbit(dev, port, speed);

Why don't you create a single ksz_port_set_xmii_speed() entry point, and
this decides whether to call ksz_set_gbit() with true or false depending
on whether the speed was 1000, and ksz_set_100_10mbit() as appropriate?

>  
>  	if (duplex)
>  		xmii_ctrl0 |= PORT_MII_FULL_DUPLEX;
> @@ -372,7 +369,6 @@ static void lan937x_config_interface(struct ksz_device *dev, int port,
>  		xmii_ctrl0 |= PORT_MII_RX_FLOW_CTRL;
>  
>  	ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_0, xmii_ctrl0);
> -	ksz_pwrite8(dev, port, REG_PORT_XMII_CTRL_1, xmii_ctrl1);

Will these remaining ksz_pwrite8 calls to REG_PORT_XMII_CTRL_0 not
overwrite what ksz_set_gbit() is doing?

>  }
>  
>  void lan937x_phylink_get_caps(struct ksz_device *dev, int port,
> diff --git a/drivers/net/dsa/microchip/lan937x_reg.h b/drivers/net/dsa/microchip/lan937x_reg.h
> index 747295d34411..b9364f6a4f8f 100644
> --- a/drivers/net/dsa/microchip/lan937x_reg.h
> +++ b/drivers/net/dsa/microchip/lan937x_reg.h
> @@ -135,7 +135,6 @@
>  #define PORT_SGMII_SEL			BIT(7)
>  #define PORT_MII_FULL_DUPLEX		BIT(6)
>  #define PORT_MII_TX_FLOW_CTRL		BIT(5)
> -#define PORT_MII_100MBIT		BIT(4)
>  #define PORT_MII_RX_FLOW_CTRL		BIT(3)
>  #define PORT_GRXC_ENABLE		BIT(0)
>  
> -- 
> 2.36.1
>