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// SPDX-License-Identifier: GPL-2.0
/*
* For transport using shared mem structure.
*
* Copyright (C) 2019 ARM Ltd.
*/
#include <linux/io.h>
#include <linux/processor.h>
#include <linux/types.h>
#include "common.h"
/*
* 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[];
};
void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer)
{
/*
* Ideally channel must be free by now unless OS timeout last
* request and platform continued to process the same, wait
* until it releases the shared memory, otherwise we may endup
* overwriting its response with new message payload or vice-versa
*/
spin_until_cond(ioread32(&shmem->channel_status) &
SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE);
/* Mark channel busy + clear error */
iowrite32(0x0, &shmem->channel_status);
iowrite32(xfer->hdr.poll_completion ? 0 : SCMI_SHMEM_FLAG_INTR_ENABLED,
&shmem->flags);
iowrite32(sizeof(shmem->msg_header) + xfer->tx.len, &shmem->length);
iowrite32(pack_scmi_header(&xfer->hdr), &shmem->msg_header);
if (xfer->tx.buf)
memcpy_toio(shmem->msg_payload, xfer->tx.buf, xfer->tx.len);
}
u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem)
{
return ioread32(&shmem->msg_header);
}
void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer)
{
xfer->hdr.status = ioread32(shmem->msg_payload);
/* Skip the length of header and status in shmem area i.e 8 bytes */
xfer->rx.len = min_t(size_t, xfer->rx.len,
ioread32(&shmem->length) - 8);
/* Take a copy to the rx buffer.. */
memcpy_fromio(xfer->rx.buf, shmem->msg_payload + 4, xfer->rx.len);
}
bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer)
{
u16 xfer_id;
xfer_id = MSG_XTRACT_TOKEN(ioread32(&shmem->msg_header));
if (xfer->hdr.seq != xfer_id)
return false;
return ioread32(&shmem->channel_status) &
(SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR |
SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE);
}
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