[PATCH] soc: imx: imx8m-blk-ctrl: set LCDIF panic read hurry level

[Marco Felsch]

On 22-12-20, Lucas Stach wrote:
> When the LCDIF block signals a panic condition due to the display FIFO
> falling below the threshold, the priority at the NoC level is boosted
> to the value set in the LCDIF_ARCACHE_CTRL register of i.MX8MP mediamix
> blk-ctrl. Same as all other blk-ctrl registers this register is reset
> when the domain is powered down. Initialize the panic hurry levels for
> both LCIF interfaces to the maximium priority (same as downstream TF-A
> and proven to work with the other priorities set in the interconnect
> driver) when coming back from power down.
> 
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>

lgtm apart a minor nit, please see below.

Reviewed-by: Marco Felsch <m.felsch at pengutronix.de>

> ---
>  drivers/soc/imx/imx8m-blk-ctrl.c | 27 +++++++++++++++++++++------
>  1 file changed, 21 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
> index 00879615a701..b93b296c47be 100644
> --- a/drivers/soc/imx/imx8m-blk-ctrl.c
> +++ b/drivers/soc/imx/imx8m-blk-ctrl.c
> @@ -4,6 +4,7 @@
>   * Copyright 2021 Pengutronix, Lucas Stach <kernel at pengutronix.de>
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/device.h>
>  #include <linux/interconnect.h>
>  #include <linux/module.h>
> @@ -649,6 +650,10 @@ static const struct imx8m_blk_ctrl_data imx8mn_disp_blk_ctl_dev_data = {
>  	.num_domains = ARRAY_SIZE(imx8mn_disp_blk_ctl_domain_data),
>  };
>  
> +#define LCDIF_ARCACHE_CTRL	0x4c
> +#define  LCDIF_1_RD_HURRY	GENMASK(15, 13)
> +#define  LCDIF_0_RD_HURRY	GENMASK(12, 10)
           ^
Was this extra space intended?

Regards,
  Marco

> +
>  static int imx8mp_media_power_notifier(struct notifier_block *nb,
>  				unsigned long action, void *data)
>  {
> @@ -662,14 +667,24 @@ static int imx8mp_media_power_notifier(struct notifier_block *nb,
>  	regmap_set_bits(bc->regmap, BLK_CLK_EN, BIT(8));
>  	regmap_set_bits(bc->regmap, BLK_SFT_RSTN, BIT(8));
>  
> -	/*
> -	 * On power up we have no software backchannel to the GPC to
> -	 * wait for the ADB handshake to happen, so we just delay for a
> -	 * bit. On power down the GPC driver waits for the handshake.
> -	 */
> -	if (action == GENPD_NOTIFY_ON)
> +	if (action == GENPD_NOTIFY_ON) {
> +		/*
> +		 * On power up we have no software backchannel to the GPC to
> +		 * wait for the ADB handshake to happen, so we just delay for a
> +		 * bit. On power down the GPC driver waits for the handshake.
> +		 */
>  		udelay(5);
>  
> +		/*
> +		 * Set panic read hurry level for both LCDIF interfaces to
> +		 * maximum priority to minimize chances of display FIFO
> +		 * underflow.
> +		 */
> +		regmap_set_bits(bc->regmap, LCDIF_ARCACHE_CTRL,
> +				FIELD_PREP(LCDIF_1_RD_HURRY, 7) |
> +				FIELD_PREP(LCDIF_0_RD_HURRY, 7));
> +	}
> +
>  	return NOTIFY_OK;
>  }
>  
> -- 
> 2.30.2
> 
> 
>