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