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Message-ID: <20231019082916.25a536fd@xps-13>
Date: Thu, 19 Oct 2023 08:29:16 +0200
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: Frank Li <Frank.Li@....com>
Cc: alexandre.belloni@...tlin.com, conor.culhane@...vaco.com,
imx@...ts.linux.dev, joe@...ches.com,
linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 Resent 3/6] i3c: master: svc: fix ibi may not return
mandatory data byte
Hi Frank,
Frank.Li@....com wrote on Wed, 18 Oct 2023 11:59:23 -0400:
> MSTATUS[RXPEND] is only updated after the data transfer cycle started. This
> creates an issue when the I3C clock is slow, and the CPU is running fast
> enough that MSTATUS[RXPEND] may not be updated when the code reach checking
> point. As a result, mandatory data are being missed.
reaches
can be missed
> Add a wait for MSTATUS[COMPLETE] to ensure that all mandatory data is
> already in FIFO.
>
> Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
> Cc: stable@...r.kernel.org
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
>
> Notes:
> Change from v1 to v2
> - update commit message
> it also works without mandatory bytes
This could be mentioned in the commit log?
>
> drivers/i3c/master/svc-i3c-master.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index abebef666b2bb..dd06b7c9333f1 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -332,6 +332,7 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
> struct i3c_ibi_slot *slot;
> unsigned int count;
> u32 mdatactrl;
> + int ret, val;
> u8 *buf;
>
> slot = i3c_generic_ibi_get_free_slot(data->ibi_pool);
> @@ -341,6 +342,13 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
> slot->len = 0;
> buf = slot->data;
>
> + ret = readl_relaxed_poll_timeout(master->regs + SVC_I3C_MSTATUS, val,
> + SVC_I3C_MSTATUS_COMPLETE(val), 0, 1000);
> + if (ret) {
> + dev_err(master->dev, "Timeout when polling for COMPLETE\n");
> + return ret;
> + }
> +
> while (SVC_I3C_MSTATUS_RXPEND(readl(master->regs + SVC_I3C_MSTATUS)) &&
> slot->len < SVC_I3C_FIFO_SIZE) {
> mdatactrl = readl(master->regs + SVC_I3C_MDATACTRL);
Thanks,
Miquèl
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