Messages in this thread | | | From | Peng Fan <> | Subject | RE: [PATCH 2/2] firmware: arm_scmi: mark channel free when init | Date | Fri, 7 Feb 2020 10:44:04 +0000 |
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> Subject: Re: [PATCH 2/2] firmware: arm_scmi: mark channel free when init > > On Fri, Feb 07, 2020 at 02:16:04AM +0000, Peng Fan wrote: > > > > > Subject: Re: [PATCH 2/2] firmware: arm_scmi: mark channel free when > > > init > > > > > > On Thu, Feb 06, 2020 at 08:57:26PM +0800, peng.fan@nxp.com wrote: > > > > From: Peng Fan <peng.fan@nxp.com> > > > > > > > > The firmware itself might not mark channel free, so let's > > > > explicitly mark it free when do initialization. > > > > > > > > Also move struct scmi_shared_mem to common.h > > > > > > > > Signed-off-by: Peng Fan <peng.fan@nxp.com> > > > > --- > > > > drivers/firmware/arm_scmi/common.h | 19 +++++++++++++++++-- > > > > drivers/firmware/arm_scmi/mailbox.c | 2 ++ > > > > drivers/firmware/arm_scmi/shmem.c | 18 ------------------ > > > > 3 files changed, 19 insertions(+), 20 deletions(-) > > > > > > > > diff --git a/drivers/firmware/arm_scmi/common.h > > > > b/drivers/firmware/arm_scmi/common.h > > > > index fd091a4ccbff..5df262a564a4 100644 > > > > --- a/drivers/firmware/arm_scmi/common.h > > > > +++ b/drivers/firmware/arm_scmi/common.h > > > > @@ -211,8 +211,23 @@ extern const struct scmi_desc > > > > scmi_mailbox_desc; void scmi_rx_callback(struct scmi_chan_info > > > > *cinfo, u32 msg_hdr); void scmi_free_channel(struct scmi_chan_info > > > > *cinfo, struct idr *idr, int id); > > > > > > > > -/* shmem related declarations */ > > > > -struct scmi_shared_mem; > > > > +/* > > > > + * SCMI specification requires all parameters, message headers, > > > > +return > > > > + * arguments or any protocol data to be expressed in little > > > > +endian > > > > + * format only. > > > > + */ > > > > +struct scmi_shared_mem { > > > > + __le32 reserved; > > > > + __le32 channel_status; > > > > +#define SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR BIT(1) > > > > +#define SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE BIT(0) > > > > + __le32 reserved1[2]; > > > > + __le32 flags; > > > > +#define SCMI_SHMEM_FLAG_INTR_ENABLED BIT(0) > > > > + __le32 length; > > > > + __le32 msg_header; > > > > + u8 msg_payload[0]; > > > > +}; > > > > > > > > void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem, > > > > struct scmi_xfer *xfer); > > > > diff --git a/drivers/firmware/arm_scmi/mailbox.c > > > > b/drivers/firmware/arm_scmi/mailbox.c > > > > index 68ed58e2a47a..2d34bf6e94e2 100644 > > > > --- a/drivers/firmware/arm_scmi/mailbox.c > > > > +++ b/drivers/firmware/arm_scmi/mailbox.c > > > > @@ -104,6 +104,8 @@ static int mailbox_chan_setup(struct > > > scmi_chan_info *cinfo, struct device *dev, > > > > cinfo->transport_info = smbox; > > > > smbox->cinfo = cinfo; > > > > > > > > + iowrite32(BIT(0), &smbox->shmem->channel_status); > > > > + > > > > > > > +arm list > > > > > If we need this then we may need to put this as a function in > > > shmem.c I am still not convinced if we can do this unconditionally, > > > i.e. will that affect Rx channel if there's notification pending > > > before we initialise. But we can deal with that later. > > > > Per understanding, channel is specific to an agent, it could not be shared. > > So the shmem binded to the channel will not be used by others. > > > > Yes > > > Since this is the initialization process, the firmware might not init the > shmem. > > > > But, is there any particular reason for firmware not to ? It means platform > holds the channel and needs to release it to agent(OSPM) in this case after > initialisation.
It is just my ATF not initialize the shmem area the leave the area with random data.
So I think that some released buggy firmware might also has similar issue.
To support buggy firmware and bug-fixed firmware, I think it might be helpful to init shmem in Linux side.
Thanks, Peng.
> > > The shmem.c shmem_tx_prepare will spin until channel free, so I did the > patch. > > Otherwise it might spin forever. > > > > Yes I guessed that to be reason. > > > I'll add a check as following > > if (tx) > > iowrite32(BIT(0), &smbox->shmem->channel_status); > > > > Not yet, I need answers to above query. > > > I not find a good place to put this in shmem.c (: > > > > Least of the problem :), let us first agree if we have to have it. > > > > > > > Also what about error fields ? I would rather clear it to 0, not > > > just BIT(0) > > > > Tx channel error should also be cleared, fix in v2. > > > > OK but wait for a while before you post for the discussion to end. > > -- > Regards, > Sudeep
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