LXR uboot/drivers/firmware/scmi/smt.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved.
   4 * Copyright (C) 2019-2020 Linaro Limited.
   5 */
   6
   7#define LOG_CATEGORY UCLASS_SCMI_AGENT
   8
   9#include <common.h>
  10#include <cpu_func.h>
  11#include <dm.h>
  12#include <dm/device_compat.h>
  13#include <errno.h>
  14#include <scmi_agent.h>
  15#include <asm/cache.h>
  16#include <asm/system.h>
  17#include <dm/ofnode.h>
  18#include <linux/compat.h>
  19#include <linux/io.h>
  20#include <linux/ioport.h>
  21
  22#include "smt.h"
  23
  24/**
  25 * Get shared memory configuration defined by the referred DT phandle
  26 * Return with a errno compliant value.
  27 */
  28int scmi_dt_get_smt_buffer(struct udevice *dev, struct scmi_smt *smt)
  29{
  30        int ret;
  31        struct ofnode_phandle_args args;
  32        struct resource resource;
  33
  34        ret = dev_read_phandle_with_args(dev, "shmem", NULL, 0, 0, &args);
  35        if (ret)
  36                return ret;
  37
  38        ret = ofnode_read_resource(args.node, 0, &resource);
  39        if (ret)
  40                return ret;
  41
  42        smt->size = resource_size(&resource);
  43        if (smt->size < sizeof(struct scmi_smt_header)) {
  44                dev_err(dev, "Shared memory buffer too small\n");
  45                return -EINVAL;
  46        }
  47
  48        smt->buf = devm_ioremap(dev, resource.start, smt->size);
  49        if (!smt->buf)
  50                return -ENOMEM;
  51
  52#ifdef CONFIG_ARM
  53        if (dcache_status())
  54                mmu_set_region_dcache_behaviour(ALIGN_DOWN((uintptr_t)smt->buf, MMU_SECTION_SIZE),
  55                                                ALIGN(smt->size, MMU_SECTION_SIZE),
  56                                                DCACHE_OFF);
  57
  58#endif
  59
  60        return 0;
  61}
  62
  63/**
  64 * Write SCMI message @msg into a SMT shared buffer @smt.
  65 * Return 0 on success and with a negative errno in case of error.
  66 */
  67int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt,
  68                          struct scmi_msg *msg)
  69{
  70        struct scmi_smt_header *hdr = (void *)smt->buf;
  71
  72        if ((!msg->in_msg && msg->in_msg_sz) ||
  73            (!msg->out_msg && msg->out_msg_sz))
  74                return -EINVAL;
  75
  76        if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) {
  77                dev_dbg(dev, "Channel busy\n");
  78                return -EBUSY;
  79        }
  80
  81        if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) ||
  82            smt->size < (sizeof(*hdr) + msg->out_msg_sz)) {
  83                dev_dbg(dev, "Buffer too small\n");
  84                return -ETOOSMALL;
  85        }
  86
  87        /* Load message in shared memory */
  88        hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
  89        hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header);
  90        hdr->msg_header = SMT_HEADER_TOKEN(0) |
  91                          SMT_HEADER_MESSAGE_TYPE(0) |
  92                          SMT_HEADER_PROTOCOL_ID(msg->protocol_id) |
  93                          SMT_HEADER_MESSAGE_ID(msg->message_id);
  94
  95        memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz);
  96
  97        return 0;
  98}
  99
 100/**
 101 * Read SCMI message from a SMT shared buffer @smt and copy it into @msg.
 102 * Return 0 on success and with a negative errno in case of error.
 103 */
 104int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt,
 105                            struct scmi_msg *msg)
 106{
 107        struct scmi_smt_header *hdr = (void *)smt->buf;
 108
 109        if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) {
 110                dev_err(dev, "Channel unexpectedly busy\n");
 111                return -EBUSY;
 112        }
 113
 114        if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) {
 115                dev_err(dev, "Channel error reported, reset channel\n");
 116                return -ECOMM;
 117        }
 118
 119        if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) {
 120                dev_err(dev, "Buffer to small\n");
 121                return -ETOOSMALL;
 122        }
 123
 124        /* Get the data */
 125        msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header);
 126        memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz);
 127
 128        return 0;
 129}
 130
 131/**
 132 * Clear SMT flags in shared buffer to allow further message exchange
 133 */
 134void scmi_clear_smt_channel(struct scmi_smt *smt)
 135{
 136        struct scmi_smt_header *hdr = (void *)smt->buf;
 137
 138        hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR;
 139}
 140