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Message-ID: <ZamGmNe0KMbEHu+0@lizhi-Precision-Tower-5810>
Date: Thu, 18 Jan 2024 15:14:16 -0500
From: Frank Li <Frank.li@....com>
To: imx@...ts.linux.dev, Miquel Raynal <miquel.raynal@...tlin.com>,
Conor Culhane <conor.culhane@...vaco.com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
"moderated list:SILVACO I3C DUAL-ROLE MASTER" <linux-i3c@...ts.infradead.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] i3c: master: svc: add support for read len bigger
than 255
On Wed, Jan 17, 2024 at 05:50:09PM -0500, Frank Li wrote:
> RDTERM is 8bit. Only support max 255 read transfer for auto terminate. Use
> manual terminate when read len bigger than 255.
>
> When left data length is FIFO size + 1, issue terminate
> (RDTERM(1) | REQUEST_NONE). So hardware will stop fetch data after next
> data.
> │ ◄────────── buff length ────────►│
> │ │
> │ ┌─┬─────────────┤
> │ │ │ FIFO SIZE │
> │ └─┴─────────────┘
> ▲
> │
> Wait FIFO Full and Issue read termniate here!!
>
> Signed-off-by: Frank Li <Frank.Li@....com>
Sorry, please hold. I found failure at corner case.
will improve and send next version later.
Frank
> ---
> drivers/i3c/master/svc-i3c-master.c | 76 ++++++++++++++++++++++++-----
> 1 file changed, 64 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index 5ee4db68988e2..58047ad357791 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -977,7 +977,7 @@ static int svc_i3c_master_do_daa(struct i3c_master_controller *m)
> }
>
> static int svc_i3c_master_read(struct svc_i3c_master *master,
> - u8 *in, unsigned int len)
> + u8 *in, unsigned int len, bool auto_term)
> {
> int offset = 0, i;
> u32 mdctrl, mstatus;
> @@ -995,16 +995,60 @@ static int svc_i3c_master_read(struct svc_i3c_master *master,
> return -ETIMEDOUT;
> }
>
> - mdctrl = readl(master->regs + SVC_I3C_MDATACTRL);
> - count = SVC_I3C_MDATACTRL_RXCOUNT(mdctrl);
> - if (offset + count > len) {
> - dev_err(master->dev, "I3C receive length too long!\n");
> - return -EINVAL;
> - }
> - for (i = 0; i < count; i++)
> - in[offset + i] = readl(master->regs + SVC_I3C_MRDATAB);
> + if (auto_term || completed) {
> + /* auto termate or early termate by target */
> + mdctrl = readl(master->regs + SVC_I3C_MDATACTRL);
> + count = SVC_I3C_MDATACTRL_RXCOUNT(mdctrl);
> + if (offset + count > len) {
> + dev_err(master->dev, "I3C receive length too long!\n");
> + return -EINVAL;
> + }
> + for (i = 0; i < count; i++)
> + in[offset + i] = readl(master->regs + SVC_I3C_MRDATAB);
> +
> + offset += count;
>
> - offset += count;
> + } else {
> + /*
> + * Controller will fill whole RX FIFO in manual mode. FIFO full can prevent
> + * controller continue fetch data from target.
> + *
> + * When left data length is FIFO size + 1, issue terminate
> + * (RDTERM(1) | REQUEST_NONE). So hardware will stop fetch data after next
> + * data.
> + *
> + * │ ◄────────── buff length ────────►│
> + * │ │
> + * │ ┌─┬─────────────┤
> + * │ │ │ FIFO SIZE │
> + * │ └─┴─────────────┘
> + * ▲
> + * │
> + * Wait FIFO Full and Issue read termniate here!!
> + */
> + mdctrl = readl_relaxed(master->regs + SVC_I3C_MDATACTRL);
> + count = SVC_I3C_MDATACTRL_RXCOUNT(mdctrl);
> +
> + if (offset + count + SVC_I3C_FIFO_SIZE < len) {
> + for (i = 0; i < count; i++) {
> + in[offset] = readl_relaxed(master->regs + SVC_I3C_MRDATAB);
> + offset++;
> + }
> + } else {
> + if (count != SVC_I3C_FIFO_SIZE)
> + continue;
> +
> + /* Issue manual read terminate at next data */
> + if (offset + SVC_I3C_FIFO_SIZE == len - 1)
> + writel_relaxed(SVC_I3C_MCTRL_REQUEST_NONE |
> + SVC_I3C_MCTRL_DIR(1) |
> + SVC_I3C_MCTRL_RDTERM(1),
> + master->regs + SVC_I3C_MCTRL);
> +
> + in[offset] = readl_relaxed(master->regs + SVC_I3C_MRDATAB);
> + offset++;
> + }
> + }
> }
>
> return offset;
> @@ -1042,9 +1086,17 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
> u8 *in, const u8 *out, unsigned int xfer_len,
> unsigned int *actual_len, bool continued)
> {
> + int rdterm = 0;
> u32 reg;
> int ret;
>
> + if (rnw)
> + rdterm = xfer_len;
> +
> + /* If read length > max RDTERM in MCTRL, using manual terminate */
> + if (xfer_len > 255)
> + rdterm = 0;
> +
> /* clean SVC_I3C_MINT_IBIWON w1c bits */
> writel(SVC_I3C_MINT_IBIWON, master->regs + SVC_I3C_MSTATUS);
>
> @@ -1053,7 +1105,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
> SVC_I3C_MCTRL_IBIRESP_NACK |
> SVC_I3C_MCTRL_DIR(rnw) |
> SVC_I3C_MCTRL_ADDR(addr) |
> - SVC_I3C_MCTRL_RDTERM(*actual_len),
> + SVC_I3C_MCTRL_RDTERM(rdterm),
> master->regs + SVC_I3C_MCTRL);
>
> ret = readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg,
> @@ -1086,7 +1138,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
> }
>
> if (rnw)
> - ret = svc_i3c_master_read(master, in, xfer_len);
> + ret = svc_i3c_master_read(master, in, xfer_len, !!rdterm);
> else
> ret = svc_i3c_master_write(master, out, xfer_len);
> if (ret < 0)
> --
> 2.34.1
>
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