Messages in this thread | | | Subject | Re: [PATCH V3] firmware: arm_scmi: Make scmi core independent of the transport type | From | Cristian Marussi <> | Date | Wed, 22 Jan 2020 12:44:32 +0000 |
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Hi
On 21/01/2020 08:27, Viresh Kumar wrote: > The SCMI specification is fairly independent of the transport protocol, > which can be a simple mailbox (already implemented) or anything else. > The current Linux implementation however is very much dependent on the > mailbox transport layer. > > This patch makes the SCMI core code (driver.c) independent of the > mailbox transport layer and moves all mailbox related code to a new > file: mailbox.c. > > We can now implement more transport protocols to transport SCMI > messages. > > The transport protocols just need to provide struct scmi_transport_ops, > with its version of the callbacks to enable exchange of SCMI messages. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[snip]
> +/* Offset of fields within the above structure */ > +#define SHMEM_CHANNEL_STATUS offsetof(struct scmi_shared_mem, channel_status) > +#define SHMEM_FLAGS offsetof(struct scmi_shared_mem, flags) > +#define SHMEM_LENGTH offsetof(struct scmi_shared_mem, length) > +#define SHMEM_MSG_HEADER offsetof(struct scmi_shared_mem, msg_header) > +#define SHMEM_MSG_PAYLOAD offsetof(struct scmi_shared_mem, msg_payload) > + > +struct scmi_info; > + > +/** > + * struct scmi_chan_info - Structure representing a SCMI channel information > + * > + * @payload: Transmit/Receive payload area > + * @dev: Reference to device in the SCMI hierarchy corresponding to this > + * channel > + * @handle: Pointer to SCMI entity handle > + * @transport_info: Transport layer related information > + */
commment is obsolete > +struct scmi_chan_info { > + struct scmi_info *info; > + struct device *dev; > + struct scmi_handle *handle; > + void *transport_info; > +}; > + > +/** > + * struct scmi_transport_ops - Structure representing a SCMI transport ops > + * > + * @send_message: Callback to send a message > + * @mark_txdone: Callback to mark tx as done > + * @chan_setup: Callback to allocate and setup a channel > + * @chan_free: Callback to free a channel > + */ commment is obsolete but I would also ask: are all of these operations supposed to be mandatory supported on any possible foreseeable transport ? (beside the obviously needed like send_message)
I'm asking because they are all called straight away from the driver core without any NULL check so that if a new transport should not need one of them it will be forced to anyway implement a dummy one to comply, which it will be needlessly invoked every time.
> +struct scmi_transport_ops { > + bool (*chan_available)(struct device *dev, int idx); > + int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev, bool tx); > + int (*chan_free)(int id, void *p, void *data); > + int (*send_message)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer); > + void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret); > + u32 (*read32)(struct scmi_chan_info *cinfo, unsigned int offset); > + void (*write32)(struct scmi_chan_info *cinfo, u32 val, unsigned int offset); > + void (*memcpy_from)(struct scmi_chan_info *cinfo, void *to, unsigned int offset, long len); > + void (*memcpy_to)(struct scmi_chan_info *cinfo, unsigned int offset, void *from, long len); > + > +}; > + > +/** > + * struct scmi_desc - Description of SoC integration > + * > + * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds) > + * @max_msg: Maximum number of messages that can be pending > + * simultaneously in the system > + * @max_msg_size: Maximum size of data per message that can be handled. > + */ comment is obsolete > +struct scmi_desc { > + struct scmi_transport_ops *ops; > + int max_rx_timeout_ms; > + int max_msg; > + int max_msg_size; > +}; > +
[big snip]
> > -static const struct scmi_desc scmi_generic_desc = { > - .max_rx_timeout_ms = 30, /* We may increase this if required */ > - .max_msg = 20, /* Limited by MBOX_TX_QUEUE_LEN */ > - .max_msg_size = 128, > -}; > - > /* Each compatible listed below must have descriptor associated with it */ > static const struct of_device_id scmi_of_match[] = { > - { .compatible = "arm,scmi", .data = &scmi_generic_desc }, > + { .compatible = "arm,scmi", .data = &scmi_mailbox_desc }, > { /* Sentinel */ }, > };
minor thing: shouldn't the chosen transport being configurable at compile time with some option like CONFIG_SCMI_TRANSPORT_MBOX ? or via DT ? (minor thing in fact since as of now we have only one transport...)
> > diff --git a/drivers/firmware/arm_scmi/mailbox.c b/drivers/firmware/arm_scmi/mailbox.c > new file mode 100644 > index 000000000000..7509e7eb262a > --- /dev/null > +++ b/drivers/firmware/arm_scmi/mailbox.c > @@ -0,0 +1,202 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * System Control and Management Interface (SCMI) Message Mailbox Transport > + * driver. > + * > + * Copyright (C) 2019 ARM Ltd. > + */ > + > +#include <linux/err.h> > +#include <linux/device.h> > +#include <linux/mailbox_client.h> > +#include <linux/of.h> > +#include <linux/of_address.h> > +#include <linux/slab.h> > + > +#include "common.h" > + > +/** > + * struct scmi_mailbox - Structure representing a SCMI mailbox transport > + * > + * @cl: Mailbox Client > + * @chan: Transmit/Receive mailbox channel > + * @cinfo: SCMI channel info > + */ comment is obsolete > +struct scmi_mailbox { > + struct mbox_client cl; > + struct mbox_chan *chan; > + struct scmi_chan_info *cinfo; > + void __iomem *payload; > +}; > +
[snip]
> +static void mailbox_memcpy_from(struct scmi_chan_info *cinfo, void *to, > + unsigned int offset, long len) > +{ > + struct scmi_mailbox *smbox = cinfo->transport_info; > + > + memcpy_fromio(to, smbox->payload + offset, len); > +} > + > +static void mailbox_memcpy_to(struct scmi_chan_info *cinfo, unsigned int offset, > + void *from, long len) > +{ > + struct scmi_mailbox *smbox = cinfo->transport_info; > + > + memcpy_toio(smbox->payload + offset, from, len); > +} > + > +static struct scmi_transport_ops scmi_mailbox_ops = { > + .chan_available = mailbox_chan_available, > + .chan_setup = mailbox_chan_setup, > + .chan_free = mailbox_chan_free, > + .send_message = mailbox_send_message, > + .mark_txdone = mailbox_mark_txdone, > + .read32 = mailbox_read32, > + .write32 = mailbox_write32, > + .memcpy_from = mailbox_memcpy_from, > + .memcpy_to = mailbox_memcpy_to, > +}; > + > +const struct scmi_desc scmi_mailbox_desc = { > + .ops = &scmi_mailbox_ops, > + .max_rx_timeout_ms = 30, /* We may increase this if required */ > + .max_msg = 20, /* Limited by MBOX_TX_QUEUE_LEN */ > + .max_msg_size = 128, > +}; >
Regards
Cristian
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