linux-kernel - Re: [PATCH v5 5/6] i3c: master: svc: wait for Manual ACK/NACK Done before next step

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Message-ID: <20241001221551.27dc2301@xps-13>
Date: Tue, 1 Oct 2024 22:15:51 +0200
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: Frank Li <Frank.Li@....com>
Cc: Conor Culhane <conor.culhane@...vaco.com>, Alexandre Belloni
 <alexandre.belloni@...tlin.com>, linux-i3c@...ts.infradead.org,
 linux-kernel@...r.kernel.org, imx@...ts.linux.dev
Subject: Re: [PATCH v5 5/6] i3c: master: svc: wait for Manual ACK/NACK Done
 before next step

Hi Frank,

Frank.Li@....com wrote on Tue, 01 Oct 2024 12:02:54 -0400:

> Wait for the controller to complete emitting ACK/NACK, otherwise the next
> command may be omitted by the hardware.
> 
> A "command done" check in svc_i3c_master_nack(ack)_ibi() and change the

Add a?

> return type to int to flag possible timeouts.
> 
> Reviewed-by: Miquel Raynal <miquel.raynal@...tlin.com>
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> Change from v3 to v4
> - rework commit message
> - add miquel's review tag
> - directly return readl(...)
> ---
>  drivers/i3c/master/svc-i3c-master.c | 29 +++++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index 1ee6ce186195c..3388c9af63fcc 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -388,10 +388,11 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
>  	return 0;
>  }
>  
> -static void svc_i3c_master_ack_ibi(struct svc_i3c_master *master,
> +static int svc_i3c_master_ack_ibi(struct svc_i3c_master *master,
>  				   bool mandatory_byte)
>  {
>  	unsigned int ibi_ack_nack;
> +	u32 reg;
>  
>  	ibi_ack_nack = SVC_I3C_MCTRL_REQUEST_IBI_ACKNACK;
>  	if (mandatory_byte)
> @@ -400,18 +401,30 @@ static void svc_i3c_master_ack_ibi(struct svc_i3c_master *master,
>  		ibi_ack_nack |= SVC_I3C_MCTRL_IBIRESP_ACK_WITHOUT_BYTE;
>  
>  	writel(ibi_ack_nack, master->regs + SVC_I3C_MCTRL);
> +
> +	return readl_poll_timeout_atomic(master->regs + SVC_I3C_MSTATUS, reg,
> +					 SVC_I3C_MSTATUS_MCTRLDONE(reg), 1, 1000);
> +
>  }
>  
> -static void svc_i3c_master_nack_ibi(struct svc_i3c_master *master)
> +static int svc_i3c_master_nack_ibi(struct svc_i3c_master *master)
>  {
> +	int ret;
> +	u32 reg;
> +
>  	writel(SVC_I3C_MCTRL_REQUEST_IBI_ACKNACK |
>  	       SVC_I3C_MCTRL_IBIRESP_NACK,
>  	       master->regs + SVC_I3C_MCTRL);
> +
> +	ret = readl_poll_timeout_atomic(master->regs + SVC_I3C_MSTATUS, reg,
> +					SVC_I3C_MSTATUS_MCTRLDONE(reg), 1, 1000);
> +	return ret;
>  }
>  
>  static int svc_i3c_master_handle_ibi_won(struct svc_i3c_master *master, u32 mstatus)
>  {
>  	u32 ibitype;
> +	int ret = 0;
>  
>  	ibitype = SVC_I3C_MSTATUS_IBITYPE(mstatus);
>  
> @@ -421,10 +434,10 @@ static int svc_i3c_master_handle_ibi_won(struct svc_i3c_master *master, u32 msta
>  	switch (ibitype) {
>  	case SVC_I3C_MSTATUS_IBITYPE_HOT_JOIN:
>  	case SVC_I3C_MSTATUS_IBITYPE_MASTER_REQUEST:
> -		svc_i3c_master_nack_ibi(master);
> +		ret = svc_i3c_master_nack_ibi(master);
>  	}
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static void svc_i3c_master_ibi_work(struct work_struct *work)
> @@ -935,7 +948,9 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master,
>  			if (ret)
>  				break;
>  		} else if (SVC_I3C_MSTATUS_IBIWON(reg)) {
> -			svc_i3c_master_handle_ibi_won(master, reg);
> +			ret = svc_i3c_master_handle_ibi_won(master, reg);
> +			if (ret)
> +				break;
>  			continue;
>  		} else if (SVC_I3C_MSTATUS_MCTRLDONE(reg)) {
>  			if (SVC_I3C_MSTATUS_STATE_IDLE(reg) &&
> @@ -1209,7 +1224,9 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
>  		 * start.
>  		 */
>  		if (SVC_I3C_MSTATUS_IBIWON(reg)) {
> -			svc_i3c_master_handle_ibi_won(master, reg);
> +			ret = svc_i3c_master_handle_ibi_won(master, reg);
> +			if (ret)
> +				goto emit_stop;
>  			continue;
>  		}
>  
> 


Thanks,
Miquèl