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LF-976 firmware: imx: scu: Ensure sequential TX 

SCU requires that all messages words are written sequentially but linux MU
driver implements multiple independent channels for each register so ordering
between different channels must be ensured by SCU API interface.

Wait for tx_done before every send to ensure that no queueing happens at the
mailbox channel level.

Reported-by: Franck LENORMAND <franck.lenormand@nxp.com>
Acked-by: Ye Li <ye.li@nxp.com>
[ Based on initial work from Franck LENORMAND <franck.lenormand@nxp.com> ]
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>

(cherry picked from commit f7021eaa04ecb71b85ae8b653d673e44a7cbcfc4)
5.4-rM2-2.2.x-imx-squashed
Leonard Crestez 2020-02-19 10:00:20 +02:00 committed by Jason Liu
parent 19bfbc82d9
commit 42c2753d88
1 changed files with 27 additions and 0 deletions
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27
drivers/firmware/imx/imx-scu.c
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@ -32,6 +32,7 @@ struct imx_sc_chan {
struct mbox_client cl;
struct mbox_chan *ch;
int idx;
struct completion tx_done;
};
struct imx_sc_ipc {
@ -103,6 +104,14 @@ int imx_scu_get_handle(struct imx_sc_ipc **ipc)
}
EXPORT_SYMBOL(imx_scu_get_handle);
/* Callback called when the word of a message is ack-ed, eg read by SCU */
static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
{
struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);
complete(&sc_chan->tx_done);
}
static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
{
struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
@ -146,6 +155,19 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
for (i = 0; i < hdr.size; i++) {
sc_chan = &sc_ipc->chans[i % 4];
/*
* SCU requires that all messages words are written
* sequentially but linux MU driver implements multiple
* independent channels for each register so ordering between
* different channels must be ensured by SCU API interface.
*
* Wait for tx_done before every send to ensure that no
* queueing happens at the mailbox channel level.
*/
wait_for_completion(&sc_chan->tx_done);
reinit_completion(&sc_chan->tx_done);
ret = mbox_send_message(sc_chan->ch, &data[i]);
if (ret < 0)
return ret;
@ -240,6 +262,11 @@ static int imx_scu_probe(struct platform_device *pdev)
cl->knows_txdone = true;
cl->rx_callback = imx_scu_rx_callback;
/* Initial tx_done completion as "done" */
cl->tx_done = imx_scu_tx_done;
init_completion(&sc_chan->tx_done);
complete(&sc_chan->tx_done);
sc_chan->sc_ipc = sc_ipc;
sc_chan->idx = i % 4;
sc_chan->ch = mbox_request_channel_byname(cl, chan_name);