Re: [PATCH 4/4] firmware: arm_ffa: Add support for FFA_MSG_SEND2

[Sudeep Holla <sudeep.holla@arm.com>]

On Tue, Apr 16, 2024 at 08:26:55AM +0100, Bertrand Marquis wrote:
> Hi Sudeep,
> 
> > On 15 Apr 2024, at 18:05, Sudeep Holla <sudeep.holla@arm.com> wrote:
> >
> > The FFA_MSG_SEND2 can be  used to transmit a partition message from
> > the Tx buffer of the sender(the driver in this case) endpoint to the Rx
> > buffer of the receiver endpoint.
> >
> > An invocation of the FFA_MSG_SEND2 transfers the ownership to the
> > receiver endpoint(or any intermediate consumer). Completion of an
> > FFA_MSG_SEND2 invocation transfers the ownership back to the sender
> > endpoint.
> >
> > The framework defines the FFA_MSG_SEND2 interface to transmit a partition
> > message from the Tx buffer of the sender to the Rx buffer of a receiver
> > and inform the scheduler that the receiver must be run.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > ---
> > drivers/firmware/arm_ffa/driver.c | 40 +++++++++++++++++++++++++++++++++++++++
> > include/linux/arm_ffa.h           |  9 +++++++++
> > 2 files changed, 49 insertions(+)
> >
> > diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> > index d5087e4f6d35..6c2602f7e7cc 100644
> > --- a/drivers/firmware/arm_ffa/driver.c
> > +++ b/drivers/firmware/arm_ffa/driver.c
> > @@ -344,6 +344,34 @@ static int ffa_msg_send_direct_req(u16 src_id, u16 dst_id, bool mode_32bit,
> > return -EINVAL;
> > }
> >
> > +static int ffa_msg_send2(u16 src_id, u16 dst_id, void *buf, size_t sz)
> > +{
> > + u32 src_dst_ids = PACK_TARGET_INFO(src_id, dst_id);
> > + struct ffa_indirect_msg_hdr *msg;
> > + ffa_value_t ret;
> > +
> > + mutex_lock(&drv_info->tx_lock);
> > +
> > + msg = drv_info->tx_buffer;
> > + msg->flags = 0;
> > + msg->res0 = 0;
> > + msg->offset = sizeof(*msg);
> > + msg->send_recv_id = src_dst_ids;
> > + msg->size = sz;
> > + memcpy(msg + msg->offset, buf, sz);
> 
> Here there should be a check that the user is not trying to send more data
> than what can fit in the TX Buffer.
>

Good point.

> Other than that LGTM.
>

Thanks!

--
Regards,
Sudeep

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