Re: [PATCH v2] net: phy: air_en8811h: add AN8811HB MCU assert/deassert support

[Eric Woudstra <ericwouds@gmail.com>]

On 3/26/26 4:35 PM, Lucien.Jheng wrote:
> AN8811HB needs a MCU soft-reset cycle before firmware loading begins.
> Assert the MCU (hold it in reset) and immediately deassert (release)
> via a dedicated PBUS register pair (0x5cf9f8 / 0x5cf9fc), accessed
> through the PHY-addr+8 MDIO bus node rather than the BUCKPBUS indirect
> path.  This clears the MCU state before the firmware loading sequence
> starts.
> 
> Add __air_pbus_reg_write() as a low-level helper for this access, then
> implement an8811hb_mcu_assert() / _deassert() on top of it.  Wire both
> into an8811hb_load_firmware() and en8811h_restart_mcu() so every
> firmware load or MCU restart on AN8811HB correctly sequences the reset
> control registers.
> 
> Fixes: 0a55766b7711 ("net: phy: air_en8811h: add Airoha AN8811HB support")
> Signed-off-by: Lucien Jheng <lucienzx159@gmail.com>
> ---
> Changes in v2:
> - Rewrite commit message: The previous wording was ambiguous,
>   as it suggested the MCU remains asserted during the entire
>   firmware loading process, rather than a quick reset cycle
>   before it starts.
>   Clarify that assert and deassert is an immediate soft-reset
>   cycle to clear MCU state before firmware loading begins.
> - Add Fixes: 0a55766b7711 ("net: phy: air_en8811h: add Airoha AN8811HB
>   support").
> - Change phydev_info() to phydev_dbg() in an8811hb_mcu_assert() and
>   an8811hb_mcu_deassert() to avoid noise during normal boot.
> 
>  drivers/net/phy/air_en8811h.c | 105 ++++++++++++++++++++++++++++++++++
>  1 file changed, 105 insertions(+)
> 
> diff --git a/drivers/net/phy/air_en8811h.c b/drivers/net/phy/air_en8811h.c
> index 29ae73e65caa..01fce1b93618 100644
> --- a/drivers/net/phy/air_en8811h.c
> +++ b/drivers/net/phy/air_en8811h.c
> @@ -170,6 +170,16 @@
>  #define   AN8811HB_CLK_DRV_CKO_LDPWD		BIT(13)
>  #define   AN8811HB_CLK_DRV_CKO_LPPWD		BIT(14)
> 
> +#define AN8811HB_MCU_SW_RST		0x5cf9f8
> +#define   AN8811HB_MCU_SW_RST_HOLD		BIT(16)
> +#define   AN8811HB_MCU_SW_RST_RUN		(BIT(16) | BIT(0))
> +#define AN8811HB_MCU_SW_START		0x5cf9fc
> +#define   AN8811HB_MCU_SW_START_EN		BIT(16)
> +
> +/* MII register constants for PBUS access (PHY addr + 8) */
> +#define AIR_PBUS_ADDR_HIGH		0x1c
> +#define AIR_PBUS_DATA_HIGH		0x10
> +
>  /* Led definitions */
>  #define EN8811H_LED_COUNT	3
> 
> @@ -254,6 +264,36 @@ static int air_phy_write_page(struct phy_device *phydev, int page)
>  	return __phy_write(phydev, AIR_EXT_PAGE_ACCESS, page);
>  }
> 
> +static int __air_pbus_reg_write(struct phy_device *phydev,
> +				u32 pbus_reg, u32 pbus_data)
> +{
> +	struct mii_bus *bus = phydev->mdio.bus;
> +	int pbus_addr = phydev->mdio.addr + 8;
> +	int ret;
> +
> +	ret = __mdiobus_write(bus, pbus_addr, AIR_EXT_PAGE_ACCESS,
> +			      upper_16_bits(pbus_reg));
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = __mdiobus_write(bus, pbus_addr, AIR_PBUS_ADDR_HIGH,
> +			      (pbus_reg & GENMASK(15, 6)) >> 6);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = __mdiobus_write(bus, pbus_addr, (pbus_reg & GENMASK(5, 2)) >> 2,
> +			      lower_16_bits(pbus_data));
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = __mdiobus_write(bus, pbus_addr, AIR_PBUS_DATA_HIGH,
> +			      upper_16_bits(pbus_data));
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +

Maybe you can use mutex_lock() and mutex_unlock() here also, like so:

static int __air_pbus_reg_write(struct mdio_device *mdio, u32 pbus_address,
				u32 pbus_data)
{
	int ret;

	ret = __mdiobus_write(mdio->bus, mdio->addr, AIR_EXT_PAGE_ACCESS,
			      (u16)(pbus_address >> 6));
	if (ret < 0)
		return ret;

	ret = __mdiobus_write(mdio->bus, mdio->addr, (pbus_address >> 2) & 0xf,
			      (u16)pbus_data);
	if (ret < 0)
		return ret;

	ret = __mdiobus_write(mdio->bus, mdio->addr, AIR_PBUS_DATA_HIGH,
			      (u16)(pbus_data >> 16));
	if (ret < 0)
		return ret;

	return 0;
}

static int air_pbus_reg_write(struct mdio_device *mdio, u32 pbus_address,
			      u32 pbus_data)
{
	int ret;

	mutex_lock(&mdio->bus->mdio_lock);

	ret = __air_pbus_reg_write(mdio, pbus_address, pbus_data);
	if (ret < 0)
		dev_err(&mdio->dev, "%s 0x%08x failed: %d\n", __func__,
			pbus_address, ret);

	mutex_unlock(&mdio->bus->mdio_lock);

	return ret;
}

static int __air_pbus_reg_read(struct mdio_device *mdio, u32 pbus_address,
			       u32 *pbus_data)
{
	int ret, pbus_data_low;

	ret = __mdiobus_write(mdio->bus, mdio->addr, AIR_EXT_PAGE_ACCESS,
			      (u16)(pbus_address >> 6));
	if (ret < 0)
		return ret;

	ret = __mdiobus_read(mdio->bus, mdio->addr, (pbus_address >> 2) & 0xf);
	if (ret < 0)
		return ret;
	pbus_data_low = ret;

	ret = __mdiobus_read(mdio->bus, mdio->addr, AIR_PBUS_DATA_HIGH);
	if (ret < 0)
		return ret;

	*pbus_data = (ret << 16) + pbus_data_low;

	return 0;
}

static int air_pbus_reg_read(struct mdio_device *mdio, u32 pbus_address,
			     u32 *pbus_data)
{
	int ret;

	mutex_lock(&mdio->bus->mdio_lock);

	ret = __air_pbus_reg_read(mdio, pbus_address, pbus_data);
	if (ret < 0)
		dev_err(&mdio->dev, "%s 0x%08x failed: %d\n", __func__,
			pbus_address, ret);

	mutex_unlock(&mdio->bus->mdio_lock);

	return ret;
}

With:

#define AIR_PBUS_DATA_HIGH		0x10


>  static int __air_buckpbus_reg_write(struct phy_device *phydev,
>  				    u32 pbus_address, u32 pbus_data)
>  {
> @@ -570,10 +610,65 @@ static int an8811hb_load_file(struct phy_device *phydev, const char *name,
>  	return ret;
>  }
> 
> +static int an8811hb_mcu_assert(struct phy_device *phydev)
> +{
> +	int ret;
> +
> +	phy_lock_mdio_bus(phydev);
> +
> +	ret = __air_pbus_reg_write(phydev, AN8811HB_MCU_SW_RST,
> +				   AN8811HB_MCU_SW_RST_HOLD);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	ret = __air_pbus_reg_write(phydev, AN8811HB_MCU_SW_START, 0);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	msleep(50);
> +	phydev_dbg(phydev, "MCU asserted\n");
> +
> +unlock:
> +	phy_unlock_mdio_bus(phydev);
> +	return ret;
> +}
> +
> +static int an8811hb_mcu_deassert(struct phy_device *phydev)
> +{
> +	int ret;
> +
> +	phy_lock_mdio_bus(phydev);
> +
> +	ret = __air_pbus_reg_write(phydev, AN8811HB_MCU_SW_START,
> +				   AN8811HB_MCU_SW_START_EN);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	ret = __air_pbus_reg_write(phydev, AN8811HB_MCU_SW_RST,
> +				   AN8811HB_MCU_SW_RST_RUN);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	msleep(50);
> +	phydev_dbg(phydev, "MCU deasserted\n");
> +
> +unlock:
> +	phy_unlock_mdio_bus(phydev);
> +	return ret;
> +}
> +
>  static int an8811hb_load_firmware(struct phy_device *phydev)
>  {
>  	int ret;
> 
> +	ret = an8811hb_mcu_assert(phydev);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = an8811hb_mcu_deassert(phydev);
> +	if (ret < 0)
> +		return ret;
> +
>  	ret = air_buckpbus_reg_write(phydev, EN8811H_FW_CTRL_1,
>  				     EN8811H_FW_CTRL_1_START);
>  	if (ret < 0)
> @@ -662,6 +757,16 @@ static int en8811h_restart_mcu(struct phy_device *phydev)
>  {
>  	int ret;
> 
> +	if (phy_id_compare_model(phydev->phy_id, AN8811HB_PHY_ID)) {
> +		ret = an8811hb_mcu_assert(phydev);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = an8811hb_mcu_deassert(phydev);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
>  	ret = air_buckpbus_reg_write(phydev, EN8811H_FW_CTRL_1,
>  				     EN8811H_FW_CTRL_1_START);
>  	if (ret < 0)
> --
> 2.34.1
>