From 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 31 Jan 2020 10:58:13 +0530 Subject: firmware: arm_scmi: Make scmi core independent of the transport type 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 and all struct shared_mem related code to a new file: shmem.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 Link: https://lore.kernel.org/r/8698a3cec199b8feab35c2339f02dc232bfd773b.1580448239.git.viresh.kumar@linaro.org Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/shmem.c | 83 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 drivers/firmware/arm_scmi/shmem.c (limited to 'drivers/firmware/arm_scmi/shmem.c') diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c new file mode 100644 index 000000000000..ca0ffd302ea2 --- /dev/null +++ b/drivers/firmware/arm_scmi/shmem.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * For transport using shared mem structure. + * + * Copyright (C) 2019 ARM Ltd. + */ + +#include +#include +#include + +#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[0]; +}; + +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); +} -- cgit v1.2.3