15c8a47a5SViresh Kumar // SPDX-License-Identifier: GPL-2.0 25c8a47a5SViresh Kumar /* 35c8a47a5SViresh Kumar * For transport using shared mem structure. 45c8a47a5SViresh Kumar * 55c8a47a5SViresh Kumar * Copyright (C) 2019 ARM Ltd. 65c8a47a5SViresh Kumar */ 75c8a47a5SViresh Kumar 85c8a47a5SViresh Kumar #include <linux/io.h> 95c8a47a5SViresh Kumar #include <linux/processor.h> 105c8a47a5SViresh Kumar #include <linux/types.h> 115c8a47a5SViresh Kumar 125c8a47a5SViresh Kumar #include "common.h" 135c8a47a5SViresh Kumar 145c8a47a5SViresh Kumar /* 155c8a47a5SViresh Kumar * SCMI specification requires all parameters, message headers, return 165c8a47a5SViresh Kumar * arguments or any protocol data to be expressed in little endian 175c8a47a5SViresh Kumar * format only. 185c8a47a5SViresh Kumar */ 195c8a47a5SViresh Kumar struct scmi_shared_mem { 205c8a47a5SViresh Kumar __le32 reserved; 215c8a47a5SViresh Kumar __le32 channel_status; 225c8a47a5SViresh Kumar #define SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR BIT(1) 235c8a47a5SViresh Kumar #define SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE BIT(0) 245c8a47a5SViresh Kumar __le32 reserved1[2]; 255c8a47a5SViresh Kumar __le32 flags; 265c8a47a5SViresh Kumar #define SCMI_SHMEM_FLAG_INTR_ENABLED BIT(0) 275c8a47a5SViresh Kumar __le32 length; 285c8a47a5SViresh Kumar __le32 msg_header; 29*4ddfb4afSGustavo A. R. Silva u8 msg_payload[]; 305c8a47a5SViresh Kumar }; 315c8a47a5SViresh Kumar 325c8a47a5SViresh Kumar void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem, 335c8a47a5SViresh Kumar struct scmi_xfer *xfer) 345c8a47a5SViresh Kumar { 355c8a47a5SViresh Kumar /* 365c8a47a5SViresh Kumar * Ideally channel must be free by now unless OS timeout last 375c8a47a5SViresh Kumar * request and platform continued to process the same, wait 385c8a47a5SViresh Kumar * until it releases the shared memory, otherwise we may endup 395c8a47a5SViresh Kumar * overwriting its response with new message payload or vice-versa 405c8a47a5SViresh Kumar */ 415c8a47a5SViresh Kumar spin_until_cond(ioread32(&shmem->channel_status) & 425c8a47a5SViresh Kumar SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE); 435c8a47a5SViresh Kumar /* Mark channel busy + clear error */ 445c8a47a5SViresh Kumar iowrite32(0x0, &shmem->channel_status); 455c8a47a5SViresh Kumar iowrite32(xfer->hdr.poll_completion ? 0 : SCMI_SHMEM_FLAG_INTR_ENABLED, 465c8a47a5SViresh Kumar &shmem->flags); 475c8a47a5SViresh Kumar iowrite32(sizeof(shmem->msg_header) + xfer->tx.len, &shmem->length); 485c8a47a5SViresh Kumar iowrite32(pack_scmi_header(&xfer->hdr), &shmem->msg_header); 495c8a47a5SViresh Kumar if (xfer->tx.buf) 505c8a47a5SViresh Kumar memcpy_toio(shmem->msg_payload, xfer->tx.buf, xfer->tx.len); 515c8a47a5SViresh Kumar } 525c8a47a5SViresh Kumar 535c8a47a5SViresh Kumar u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem) 545c8a47a5SViresh Kumar { 555c8a47a5SViresh Kumar return ioread32(&shmem->msg_header); 565c8a47a5SViresh Kumar } 575c8a47a5SViresh Kumar 585c8a47a5SViresh Kumar void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, 595c8a47a5SViresh Kumar struct scmi_xfer *xfer) 605c8a47a5SViresh Kumar { 615c8a47a5SViresh Kumar xfer->hdr.status = ioread32(shmem->msg_payload); 625c8a47a5SViresh Kumar /* Skip the length of header and status in shmem area i.e 8 bytes */ 635c8a47a5SViresh Kumar xfer->rx.len = min_t(size_t, xfer->rx.len, 645c8a47a5SViresh Kumar ioread32(&shmem->length) - 8); 655c8a47a5SViresh Kumar 665c8a47a5SViresh Kumar /* Take a copy to the rx buffer.. */ 675c8a47a5SViresh Kumar memcpy_fromio(xfer->rx.buf, shmem->msg_payload + 4, xfer->rx.len); 685c8a47a5SViresh Kumar } 695c8a47a5SViresh Kumar 705c8a47a5SViresh Kumar bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem, 715c8a47a5SViresh Kumar struct scmi_xfer *xfer) 725c8a47a5SViresh Kumar { 735c8a47a5SViresh Kumar u16 xfer_id; 745c8a47a5SViresh Kumar 755c8a47a5SViresh Kumar xfer_id = MSG_XTRACT_TOKEN(ioread32(&shmem->msg_header)); 765c8a47a5SViresh Kumar 775c8a47a5SViresh Kumar if (xfer->hdr.seq != xfer_id) 785c8a47a5SViresh Kumar return false; 795c8a47a5SViresh Kumar 805c8a47a5SViresh Kumar return ioread32(&shmem->channel_status) & 815c8a47a5SViresh Kumar (SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR | 825c8a47a5SViresh Kumar SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE); 835c8a47a5SViresh Kumar } 84