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/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/remoteproc/mtk_scp.h>
  13
  14 #include "mtk_common.h"
  15
  16 /**
  17  * scp_ipi_register() - register an ipi function
  18  *
  19  * @scp:        mtk_scp structure
  20  * @id:         IPI ID
  21  * @handler:    IPI handler
  22  * @priv:       private data for IPI handler
  23  *
  24  * Register an ipi function to receive ipi interrupt from SCP.
  25  *
  26  * Returns 0 if ipi registers successfully, -error on error.
  27  */
  28 int scp_ipi_register(struct mtk_scp *scp,
  29                      u32 id,
  30                      scp_ipi_handler_t handler,
  31                      void *priv)
  32 {
  33         if (!scp) {
  34                 dev_err(scp->dev, "scp device is not ready\n");
  35                 return -EPROBE_DEFER;
  36         }
  37
  38         if (WARN_ON(id >= SCP_IPI_MAX) || WARN_ON(handler == NULL))
  39                 return -EINVAL;
  40
  41         scp_ipi_lock(scp, id);
  42         scp->ipi_desc[id].handler = handler;
  43         scp->ipi_desc[id].priv = priv;
  44         scp_ipi_unlock(scp, id);
  45
  46         return 0;
  47 }
  48 EXPORT_SYMBOL_GPL(scp_ipi_register);
  49
  50 /**
  51  * scp_ipi_unregister() - unregister an ipi function
  52  *
  53  * @scp:        mtk_scp structure
  54  * @id:         IPI ID
  55  *
  56  * Unregister an ipi function to receive ipi interrupt from SCP.
  57  */
  58 void scp_ipi_unregister(struct mtk_scp *scp, u32 id)
  59 {
  60         if (!scp)
  61                 return;
  62
  63         if (WARN_ON(id >= SCP_IPI_MAX))
  64                 return;
  65
  66         scp_ipi_lock(scp, id);
  67         scp->ipi_desc[id].handler = NULL;
  68         scp->ipi_desc[id].priv = NULL;
  69         scp_ipi_unlock(scp, id);
  70 }
  71 EXPORT_SYMBOL_GPL(scp_ipi_unregister);
  72
  73 /*
  74  * scp_memcpy_aligned() - Copy src to dst, where dst is in SCP SRAM region.
  75  *
  76  * @dst:        Pointer to the destination buffer, should be in SCP SRAM region.
  77  * @src:        Pointer to the source buffer.
  78  * @len:        Length of the source buffer to be copied.
  79  *
  80  * Since AP access of SCP SRAM don't support byte write, this always write a
  81  * full word at a time, and may cause some extra bytes to be written at the
  82  * beginning & ending of dst.
  83  */
  84 void scp_memcpy_aligned(void __iomem *dst, const void *src, unsigned int len)
  85 {
  86         void __iomem *ptr;
  87         u32 val;
  88         unsigned int i = 0, remain;
  89
  90         if (!IS_ALIGNED((unsigned long)dst, 4)) {
  91                 ptr = (void __iomem *)ALIGN_DOWN((unsigned long)dst, 4);
  92                 i = 4 - (dst - ptr);
  93                 val = readl_relaxed(ptr);
  94                 memcpy((u8 *)&val + (4 - i), src, i);
  95                 writel_relaxed(val, ptr);
  96         }
  97
  98         __iowrite32_copy(dst + i, src + i, (len - i) / 4);
  99         remain = (len - i) % 4;
 100
 101         if (remain > 0) {
 102                 val = readl_relaxed(dst + len - remain);
 103                 memcpy(&val, src + len - remain, remain);
 104                 writel_relaxed(val, dst + len - remain);
 105         }
 106 }
 107 EXPORT_SYMBOL_GPL(scp_memcpy_aligned);
 108
 109 /**
 110  * scp_ipi_lock() - Lock before operations of an IPI ID
 111  *
 112  * @scp:        mtk_scp structure
 113  * @id:         IPI ID
 114  *
 115  * Note: This should not be used by drivers other than mtk_scp.
 116  */
 117 void scp_ipi_lock(struct mtk_scp *scp, u32 id)
 118 {
 119         if (WARN_ON(id >= SCP_IPI_MAX))
 120                 return;
 121         mutex_lock(&scp->ipi_desc[id].lock);
 122 }
 123 EXPORT_SYMBOL_GPL(scp_ipi_lock);
 124
 125 /**
 126  * scp_ipi_lock() - Unlock after operations of an IPI ID
 127  *
 128  * @scp:        mtk_scp structure
 129  * @id:         IPI ID
 130  *
 131  * Note: This should not be used by drivers other than mtk_scp.
 132  */
 133 void scp_ipi_unlock(struct mtk_scp *scp, u32 id)
 134 {
 135         if (WARN_ON(id >= SCP_IPI_MAX))
 136                 return;
 137         mutex_unlock(&scp->ipi_desc[id].lock);
 138 }
 139 EXPORT_SYMBOL_GPL(scp_ipi_unlock);
 140
 141 /**
 142  * scp_ipi_send() - send data from AP to scp.
 143  *
 144  * @scp:        mtk_scp structure
 145  * @id:         IPI ID
 146  * @buf:        the data buffer
 147  * @len:        the data buffer length
 148  * @wait:       number of msecs to wait for ack. 0 to skip waiting.
 149  *
 150  * This function is thread-safe. When this function returns,
 151  * SCP has received the data and starts the processing.
 152  * When the processing completes, IPI handler registered
 153  * by scp_ipi_register will be called in interrupt context.
 154  *
 155  * Returns 0 if sending data successfully, -error on error.
 156  **/
 157 int scp_ipi_send(struct mtk_scp *scp, u32 id, void *buf, unsigned int len,
 158                  unsigned int wait)
 159 {
 160         struct mtk_share_obj __iomem *send_obj = scp->send_buf;
 161         unsigned long timeout;
 162         int ret;
 163
 164         if (WARN_ON(id <= SCP_IPI_INIT) || WARN_ON(id >= SCP_IPI_MAX) ||
 165             WARN_ON(id == SCP_IPI_NS_SERVICE) ||
 166             WARN_ON(len > sizeof(send_obj->share_buf)) || WARN_ON(!buf))
 167                 return -EINVAL;
 168
 169         mutex_lock(&scp->send_lock);
 170
 171         ret = clk_prepare_enable(scp->clk);
 172         if (ret) {
 173                 dev_err(scp->dev, "failed to enable clock\n");
 174                 goto unlock_mutex;
 175         }
 176
 177          /* Wait until SCP receives the last command */
 178         timeout = jiffies + msecs_to_jiffies(2000);
 179         do {
 180                 if (time_after(jiffies, timeout)) {
 181                         dev_err(scp->dev, "%s: IPI timeout!\n", __func__);
 182                         ret = -ETIMEDOUT;
 183                         goto clock_disable;
 184                 }
 185         } while (readl(scp->reg_base + MT8183_HOST_TO_SCP));
 186
 187         scp_memcpy_aligned(send_obj->share_buf, buf, len);
 188
 189         writel(len, &send_obj->len);
 190         writel(id, &send_obj->id);
 191
 192         scp->ipi_id_ack[id] = false;
 193         /* send the command to SCP */
 194         writel(MT8183_HOST_IPC_INT_BIT, scp->reg_base + MT8183_HOST_TO_SCP);
 195
 196         if (wait) {
 197                 /* wait for SCP's ACK */
 198                 timeout = msecs_to_jiffies(wait);
 199                 ret = wait_event_timeout(scp->ack_wq,
 200                                          scp->ipi_id_ack[id],
 201                                          timeout);
 202                 scp->ipi_id_ack[id] = false;
 203                 if (WARN(!ret, "scp ipi %d ack time out !", id))
 204                         ret = -EIO;
 205                 else
 206                         ret = 0;
 207         }
 208
 209 clock_disable:
 210         clk_disable_unprepare(scp->clk);
 211 unlock_mutex:
 212         mutex_unlock(&scp->send_lock);
 213
 214         return ret;
 215 }
 216 EXPORT_SYMBOL_GPL(scp_ipi_send);
 217
 218 MODULE_LICENSE("GPL v2");
 219 MODULE_DESCRIPTION("MediaTek scp IPI interface");