drivers/remoteproc/mtk_scp_ipi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright (c) 2019 MediaTek Inc.
   4
   5 #include <asm/barrier.h>
   6 #include <linux/clk.h>
   7 #include <linux/err.h>
   8 #include <linux/io.h>
   9 #include <linux/iopoll.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/time64.h>
  14 #include <linux/remoteproc/mtk_scp.h>
  15
  16 #include "mtk_common.h"
  17
  18 #define SCP_TIMEOUT_US          (2000 * USEC_PER_MSEC)
  19
  20 /**
  21  * scp_ipi_register() - register an ipi function
  22  *
  23  * @scp:        mtk_scp structure
  24  * @id:         IPI ID
  25  * @handler:    IPI handler
  26  * @priv:       private data for IPI handler
  27  *
  28  * Register an ipi function to receive ipi interrupt from SCP.
  29  *
  30  * Return: 0 if ipi registers successfully, -error on error.
  31  */
  32 int scp_ipi_register(struct mtk_scp *scp,
  33                      u32 id,
  34                      scp_ipi_handler_t handler,
  35                      void *priv)
  36 {
  37         if (!scp)
  38                 return -EPROBE_DEFER;
  39
  40         if (WARN_ON(id >= SCP_IPI_MAX) || WARN_ON(handler == NULL))
  41                 return -EINVAL;
  42
  43         scp_ipi_lock(scp, id);
  44         scp->ipi_desc[id].handler = handler;
  45         scp->ipi_desc[id].priv = priv;
  46         scp_ipi_unlock(scp, id);
  47
  48         return 0;
  49 }
  50 EXPORT_SYMBOL_GPL(scp_ipi_register);
  51
  52 /**
  53  * scp_ipi_unregister() - unregister an ipi function
  54  *
  55  * @scp:        mtk_scp structure
  56  * @id:         IPI ID
  57  *
  58  * Unregister an ipi function to receive ipi interrupt from SCP.
  59  */
  60 void scp_ipi_unregister(struct mtk_scp *scp, u32 id)
  61 {
  62         if (!scp)
  63                 return;
  64
  65         if (WARN_ON(id >= SCP_IPI_MAX))
  66                 return;
  67
  68         scp_ipi_lock(scp, id);
  69         scp->ipi_desc[id].handler = NULL;
  70         scp->ipi_desc[id].priv = NULL;
  71         scp_ipi_unlock(scp, id);
  72 }
  73 EXPORT_SYMBOL_GPL(scp_ipi_unregister);
  74
  75 /*
  76  * scp_memcpy_aligned() - Copy src to dst, where dst is in SCP SRAM region.
  77  *
  78  * @dst:        Pointer to the destination buffer, should be in SCP SRAM region.
  79  * @src:        Pointer to the source buffer.
  80  * @len:        Length of the source buffer to be copied.
  81  *
  82  * Since AP access of SCP SRAM don't support byte write, this always write a
  83  * full word at a time, and may cause some extra bytes to be written at the
  84  * beginning & ending of dst.
  85  */
  86 void scp_memcpy_aligned(void __iomem *dst, const void *src, unsigned int len)
  87 {
  88         void __iomem *ptr;
  89         u32 val;
  90         unsigned int i = 0, remain;
  91
  92         if (!IS_ALIGNED((unsigned long)dst, 4)) {
  93                 ptr = (void __iomem *)ALIGN_DOWN((unsigned long)dst, 4);
  94                 i = 4 - (dst - ptr);
  95                 val = readl_relaxed(ptr);
  96                 memcpy((u8 *)&val + (4 - i), src, i);
  97                 writel_relaxed(val, ptr);
  98         }
  99
 100         __iowrite32_copy(dst + i, src + i, (len - i) / 4);
 101         remain = (len - i) % 4;
 102
 103         if (remain > 0) {
 104                 val = readl_relaxed(dst + len - remain);
 105                 memcpy(&val, src + len - remain, remain);
 106                 writel_relaxed(val, dst + len - remain);
 107         }
 108 }
 109 EXPORT_SYMBOL_GPL(scp_memcpy_aligned);
 110
 111 /**
 112  * scp_ipi_lock() - Lock before operations of an IPI ID
 113  *
 114  * @scp:        mtk_scp structure
 115  * @id:         IPI ID
 116  *
 117  * Note: This should not be used by drivers other than mtk_scp.
 118  */
 119 void scp_ipi_lock(struct mtk_scp *scp, u32 id)
 120 {
 121         if (WARN_ON(id >= SCP_IPI_MAX))
 122                 return;
 123         mutex_lock(&scp->ipi_desc[id].lock);
 124 }
 125 EXPORT_SYMBOL_GPL(scp_ipi_lock);
 126
 127 /**
 128  * scp_ipi_unlock() - Unlock after operations of an IPI ID
 129  *
 130  * @scp:        mtk_scp structure
 131  * @id:         IPI ID
 132  *
 133  * Note: This should not be used by drivers other than mtk_scp.
 134  */
 135 void scp_ipi_unlock(struct mtk_scp *scp, u32 id)
 136 {
 137         if (WARN_ON(id >= SCP_IPI_MAX))
 138                 return;
 139         mutex_unlock(&scp->ipi_desc[id].lock);
 140 }
 141 EXPORT_SYMBOL_GPL(scp_ipi_unlock);
 142
 143 /**
 144  * scp_ipi_send() - send data from AP to scp.
 145  *
 146  * @scp:        mtk_scp structure
 147  * @id:         IPI ID
 148  * @buf:        the data buffer
 149  * @len:        the data buffer length
 150  * @wait:       number of msecs to wait for ack. 0 to skip waiting.
 151  *
 152  * This function is thread-safe. When this function returns,
 153  * SCP has received the data and starts the processing.
 154  * When the processing completes, IPI handler registered
 155  * by scp_ipi_register will be called in interrupt context.
 156  *
 157  * Return: 0 if sending data successfully, -error on error.
 158  **/
 159 int scp_ipi_send(struct mtk_scp *scp, u32 id, void *buf, unsigned int len,
 160                  unsigned int wait)
 161 {
 162         struct mtk_share_obj __iomem *send_obj = scp->send_buf;
 163         u32 val;
 164         int ret;
 165         const struct mtk_scp_sizes_data *scp_sizes;
 166
 167         scp_sizes = scp->data->scp_sizes;
 168
 169         if (WARN_ON(id <= SCP_IPI_INIT) || WARN_ON(id >= SCP_IPI_MAX) ||
 170             WARN_ON(id == SCP_IPI_NS_SERVICE) ||
 171             WARN_ON(len > scp_sizes->ipi_share_buffer_size) || WARN_ON(!buf))
 172                 return -EINVAL;
 173
 174         ret = clk_prepare_enable(scp->clk);
 175         if (ret) {
 176                 dev_err(scp->dev, "failed to enable clock\n");
 177                 return ret;
 178         }
 179
 180         mutex_lock(&scp->send_lock);
 181
 182          /* Wait until SCP receives the last command */
 183         ret = readl_poll_timeout_atomic(scp->cluster->reg_base + scp->data->host_to_scp_reg,
 184                                         val, !val, 0, SCP_TIMEOUT_US);
 185         if (ret) {
 186                 dev_err(scp->dev, "%s: IPI timeout!\n", __func__);
 187                 goto unlock_mutex;
 188         }
 189
 190         scp_memcpy_aligned(&send_obj->share_buf, buf, len);
 191
 192         writel(len, &send_obj->len);
 193         writel(id, &send_obj->id);
 194
 195         scp->ipi_id_ack[id] = false;
 196         /* send the command to SCP */
 197         writel(scp->data->host_to_scp_int_bit,
 198                scp->cluster->reg_base + scp->data->host_to_scp_reg);
 199
 200         if (wait) {
 201                 /* wait for SCP's ACK */
 202                 ret = wait_event_timeout(scp->ack_wq,
 203                                          scp->ipi_id_ack[id],
 204                                          msecs_to_jiffies(wait));
 205                 scp->ipi_id_ack[id] = false;
 206                 if (WARN(!ret, "scp ipi %d ack time out !", id))
 207                         ret = -EIO;
 208                 else
 209                         ret = 0;
 210         }
 211
 212 unlock_mutex:
 213         mutex_unlock(&scp->send_lock);
 214         clk_disable_unprepare(scp->clk);
 215
 216         return ret;
 217 }
 218 EXPORT_SYMBOL_GPL(scp_ipi_send);
 219
 220 MODULE_LICENSE("GPL v2");
 221 MODULE_DESCRIPTION("MediaTek scp IPI interface");