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Date: Mon, 2 Mar 2020 10:47:26 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: peng.fan@....com, shawnguo@...nel.org, s.hauer@...gutronix.de,
jassisinghbrar@...il.com, robh+dt@...nel.org
Cc: aisheng.dong@....com, Anson.Huang@....com,
linux-kernel@...r.kernel.org, linux-imx@....com,
kernel@...gutronix.de, leonard.crestez@....com, festevam@...il.com,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V3 3/4] mailbox: imx: add SCU MU support
Hi,
On 26.02.20 05:40, peng.fan@....com wrote:
> From: Peng Fan <peng.fan@....com>
>
> i.MX8/8X SCU MU is dedicated for communication between SCU and Cortex-A
> cores from hardware design, and could not be reused for other purpose.
>
> Per i.MX8/8X Reference mannual, Chapter "12.9.2.3.2 Messaging Examples",
> Passing short messages: Transmit register(s) can be used to pass
> short messages from one to four words in length. For example, when
> a four-word message is desired, only one of the registers needs to
> have its corresponding interrupt enable bit set at the receiver side;
> the message’s first three words are written to the registers whose
> interrupt is masked, and the fourth word is written to the other
> register (which triggers an interrupt at the receiver side).
>
> i.MX8/8X SCU firmware IPC is an implementation of passing short
> messages. But current imx-mailbox driver only support one word
> message, i.MX8/8X linux side firmware has to request four TX
> and four RX to support IPC to SCU firmware. This is low efficent
> and more interrupts triggered compared with one TX and
> one RX.
>
> To make SCU MU work,
> - parse the size of msg.
> - Only enable TR0/RR0 interrupt for transmit/receive message.
> - For TX/RX, only support one TX channel and one RX channel
>
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>
> V3:
> Added scu type tx/rx and SCU MU type
>
> drivers/mailbox/imx-mailbox.c | 65 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 64 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mailbox/imx-mailbox.c b/drivers/mailbox/imx-mailbox.c
> index 901a3431fdb5..41664a64c5fd 100644
> --- a/drivers/mailbox/imx-mailbox.c
> +++ b/drivers/mailbox/imx-mailbox.c
> @@ -4,6 +4,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/firmware/imx/ipc.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/kernel.h>
> @@ -38,11 +39,17 @@ enum imx_mu_chan_type {
>
> enum imx_mu_type {
> IMX_MU_TYPE_GENERIC,
> + IMX_MU_TYPE_SCU,
> };
>
> struct imx_mu_priv;
> struct imx_mu_con_priv;
>
> +struct imx_sc_rpc_msg_max {
> + struct imx_sc_rpc_msg hdr;
> + u32 data[7];
> +} __packed __aligned(4);;
> +
> struct imx_mu_dcfg {
> enum imx_mu_type type;
> int (*tx)(struct imx_mu_priv *priv, struct imx_mu_con_priv *cp, void *data);
> @@ -141,6 +148,48 @@ static int imx_mu_generic_rx(struct imx_mu_priv *priv,
> return 0;
> }
>
> +static int imx_mu_scu_tx(struct imx_mu_priv *priv,
> + struct imx_mu_con_priv *cp,
> + void *data)
> +{
> + struct imx_sc_rpc_msg_max *msg = data;
> + u32 *arg = data;
> + int i;
> +
> + switch (cp->type) {
> + case IMX_MU_TYPE_TX:
please add sanity check if msg->hdr.size can be handled by this driver version.
> + for (i = 0; i < msg->hdr.size; i++) {
> + imx_mu_write(priv, *arg++,
> + priv->dcfg->xTR[i % 4]);
> + }
> + imx_mu_xcr_rmw(priv, IMX_MU_xCR_TIEn(cp->idx), 0);
> + break;
> + default:
> + dev_warn_ratelimited(priv->dev, "Send data on wrong channel type: %d\n", cp->type);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int imx_mu_scu_rx(struct imx_mu_priv *priv,
> + struct imx_mu_con_priv *cp)
> +{
> + struct imx_sc_rpc_msg_max msg;
> + u32 *data = (u32 *)&msg;
> + int i;
> +
> + imx_mu_xcr_rmw(priv, 0, IMX_MU_xCR_RIEn(0));
> + *data++ = imx_mu_read(priv, priv->dcfg->xRR[0]);
please add sanity check. the message size should not be higher then sizeof(msg)
> + for (i = 1; i < msg.hdr.size; i++)
> + *data++ = imx_mu_read(priv, priv->dcfg->xRR[i % 4]);
> +
> + imx_mu_xcr_rmw(priv, IMX_MU_xCR_RIEn(0), 0);
Please do not forget to handle properly new msg size in your rx_callback. In previous
implementation the message size was 4byte.
> + mbox_chan_received_data(cp->chan, (void *)&msg);
> +
> + return 0;
> +}
> +
> static void imx_mu_txdb_tasklet(unsigned long data)
> {
> struct imx_mu_con_priv *cp = (struct imx_mu_con_priv *)data;
> @@ -274,6 +323,7 @@ static struct mbox_chan * imx_mu_xlate(struct mbox_controller *mbox,
> const struct of_phandle_args *sp)
> {
> u32 type, idx, chan;
> + struct imx_mu_priv *priv = to_imx_mu_priv(mbox);
>
> if (sp->args_count != 2) {
> dev_err(mbox->dev, "Invalid argument count %d\n", sp->args_count);
> @@ -284,7 +334,9 @@ static struct mbox_chan * imx_mu_xlate(struct mbox_controller *mbox,
> idx = sp->args[1]; /* index */
> chan = type * 4 + idx;
>
> - if (chan >= mbox->num_chans) {
> + if (chan >= mbox->num_chans ||
> + (priv->dcfg->type == IMX_MU_TYPE_SCU &&
> + type < IMX_MU_TYPE_TXDB && idx > 0)) {
We need this check since mbox->num_chans do not reflects new reality. Now we have only 2
channels. One RX and one TX. No idea if we need doorbell channels for SCU. If doorbells
are not supported, it is better to add a separate imx_mu_xlate for SCU
and add SCU specific channel init in probe in addition to:
for (i = 0; i < IMX_MU_CHANS; i++) {
struct imx_mu_con_priv *cp = &priv->con_priv[i];
cp->idx = i % 4;
cp->type = i >> 2;
cp->chan = &priv->mbox_chans[i];
priv->mbox_chans[i].con_priv = cp;
snprintf(cp->irq_desc, sizeof(cp->irq_desc),
"imx_mu_chan[%i-%i]", cp->type, cp->idx);
}
There is no need to init unsupported channels. Please pack it in separate function
> dev_err(mbox->dev, "Not supported channel number: %d. (type: %d, idx: %d)\n", chan, type, idx);
> return ERR_PTR(-EINVAL);
> }
> @@ -401,9 +453,20 @@ static const struct imx_mu_dcfg imx_mu_cfg_imx7ulp = {
> .xCR = 0x64,
> };
>
> +static const struct imx_mu_dcfg imx_mu_cfg_imx8_scu = {
> + .type = IMX_MU_TYPE_SCU,
> + .tx = imx_mu_scu_tx,
> + .rx = imx_mu_scu_rx,
> + .xTR = {0x0, 0x4, 0x8, 0xc},
> + .xRR = {0x10, 0x14, 0x18, 0x1c},
> + .xSR = 0x20,
> + .xCR = 0x24,
> +};
> +
> static const struct of_device_id imx_mu_dt_ids[] = {
> { .compatible = "fsl,imx7ulp-mu", .data = &imx_mu_cfg_imx7ulp },
> { .compatible = "fsl,imx6sx-mu", .data = &imx_mu_cfg_imx6sx },
> + { .compatible = "fsl,imx8-mu-scu", .data = &imx_mu_cfg_imx8_scu },
> { },
> };
> MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);
>
Kind regards,
Oleksij Rempel
--
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