root/drivers/hid/intel-ish-hid/ishtp/dma-if.c

DEFINITIONS

1. ishtp_cl_alloc_dma_buf
2. ishtp_cl_free_dma_buf
3. ishtp_cl_get_dma_send_buf
4. ishtp_cl_release_dma_acked_mem

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ISHTP DMA I/F functions
   4  *
   5  * Copyright (c) 2003-2016, Intel Corporation.
   6  */
   7 
   8 #include <linux/slab.h>
   9 #include <linux/sched.h>
  10 #include <linux/wait.h>
  11 #include <linux/delay.h>
  12 #include <linux/dma-mapping.h>
  13 #include "ishtp-dev.h"
  14 #include "client.h"
  15 
  16 /**
  17  * ishtp_cl_alloc_dma_buf() - Allocate DMA RX and TX buffer
  18  * @dev: ishtp device
  19  *
  20  * Allocate RX and TX DMA buffer once during bus setup.
  21  * It allocates 1MB, RX and TX DMA buffer, which are divided
  22  * into slots.
  23  */
  24 void    ishtp_cl_alloc_dma_buf(struct ishtp_device *dev)
  25 {
  26         dma_addr_t      h;
  27 
  28         if (dev->ishtp_host_dma_tx_buf)
  29                 return;
  30 
  31         dev->ishtp_host_dma_tx_buf_size = 1024*1024;
  32         dev->ishtp_host_dma_rx_buf_size = 1024*1024;
  33 
  34         /* Allocate Tx buffer and init usage bitmap */
  35         dev->ishtp_host_dma_tx_buf = dma_alloc_coherent(dev->devc,
  36                                         dev->ishtp_host_dma_tx_buf_size,
  37                                         &h, GFP_KERNEL);
  38         if (dev->ishtp_host_dma_tx_buf)
  39                 dev->ishtp_host_dma_tx_buf_phys = h;
  40 
  41         dev->ishtp_dma_num_slots = dev->ishtp_host_dma_tx_buf_size /
  42                                                 DMA_SLOT_SIZE;
  43 
  44         dev->ishtp_dma_tx_map = kcalloc(dev->ishtp_dma_num_slots,
  45                                         sizeof(uint8_t),
  46                                         GFP_KERNEL);
  47         spin_lock_init(&dev->ishtp_dma_tx_lock);
  48 
  49         /* Allocate Rx buffer */
  50         dev->ishtp_host_dma_rx_buf = dma_alloc_coherent(dev->devc,
  51                                         dev->ishtp_host_dma_rx_buf_size,
  52                                          &h, GFP_KERNEL);
  53 
  54         if (dev->ishtp_host_dma_rx_buf)
  55                 dev->ishtp_host_dma_rx_buf_phys = h;
  56 }
  57 
  58 /**
  59  * ishtp_cl_free_dma_buf() - Free DMA RX and TX buffer
  60  * @dev: ishtp device
  61  *
  62  * Free DMA buffer when all clients are released. This is
  63  * only happens during error path in ISH built in driver
  64  * model
  65  */
  66 void    ishtp_cl_free_dma_buf(struct ishtp_device *dev)
  67 {
  68         dma_addr_t      h;
  69 
  70         if (dev->ishtp_host_dma_tx_buf) {
  71                 h = dev->ishtp_host_dma_tx_buf_phys;
  72                 dma_free_coherent(dev->devc, dev->ishtp_host_dma_tx_buf_size,
  73                                   dev->ishtp_host_dma_tx_buf, h);
  74         }
  75 
  76         if (dev->ishtp_host_dma_rx_buf) {
  77                 h = dev->ishtp_host_dma_rx_buf_phys;
  78                 dma_free_coherent(dev->devc, dev->ishtp_host_dma_rx_buf_size,
  79                                   dev->ishtp_host_dma_rx_buf, h);
  80         }
  81 
  82         kfree(dev->ishtp_dma_tx_map);
  83         dev->ishtp_host_dma_tx_buf = NULL;
  84         dev->ishtp_host_dma_rx_buf = NULL;
  85         dev->ishtp_dma_tx_map = NULL;
  86 }
  87 
  88 /*
  89  * ishtp_cl_get_dma_send_buf() - Get a DMA memory slot
  90  * @dev:        ishtp device
  91  * @size:       Size of memory to get
  92  *
  93  * Find and return free address of "size" bytes in dma tx buffer.
  94  * the function will mark this address as "in-used" memory.
  95  *
  96  * Return: NULL when no free buffer else a buffer to copy
  97  */
  98 void *ishtp_cl_get_dma_send_buf(struct ishtp_device *dev,
  99                                 uint32_t size)
 100 {
 101         unsigned long   flags;
 102         int i, j, free;
 103         /* additional slot is needed if there is rem */
 104         int required_slots = (size / DMA_SLOT_SIZE)
 105                 + 1 * (size % DMA_SLOT_SIZE != 0);
 106 
 107         spin_lock_irqsave(&dev->ishtp_dma_tx_lock, flags);
 108         for (i = 0; i <= (dev->ishtp_dma_num_slots - required_slots); i++) {
 109                 free = 1;
 110                 for (j = 0; j < required_slots; j++)
 111                         if (dev->ishtp_dma_tx_map[i+j]) {
 112                                 free = 0;
 113                                 i += j;
 114                                 break;
 115                         }
 116                 if (free) {
 117                         /* mark memory as "caught" */
 118                         for (j = 0; j < required_slots; j++)
 119                                 dev->ishtp_dma_tx_map[i+j] = 1;
 120                         spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
 121                         return (i * DMA_SLOT_SIZE) +
 122                                 (unsigned char *)dev->ishtp_host_dma_tx_buf;
 123                 }
 124         }
 125         spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
 126         dev_err(dev->devc, "No free DMA buffer to send msg\n");
 127         return NULL;
 128 }
 129 
 130 /*
 131  * ishtp_cl_release_dma_acked_mem() - Release DMA memory slot
 132  * @dev:        ishtp device
 133  * @msg_addr:   message address of slot
 134  * @size:       Size of memory to get
 135  *
 136  * Release_dma_acked_mem - returnes the acked memory to free list.
 137  * (from msg_addr, size bytes long)
 138  */
 139 void ishtp_cl_release_dma_acked_mem(struct ishtp_device *dev,
 140                                     void *msg_addr,
 141                                     uint8_t size)
 142 {
 143         unsigned long   flags;
 144         int acked_slots = (size / DMA_SLOT_SIZE)
 145                 + 1 * (size % DMA_SLOT_SIZE != 0);
 146         int i, j;
 147 
 148         if ((msg_addr - dev->ishtp_host_dma_tx_buf) % DMA_SLOT_SIZE) {
 149                 dev_err(dev->devc, "Bad DMA Tx ack address\n");
 150                 return;
 151         }
 152 
 153         i = (msg_addr - dev->ishtp_host_dma_tx_buf) / DMA_SLOT_SIZE;
 154         spin_lock_irqsave(&dev->ishtp_dma_tx_lock, flags);
 155         for (j = 0; j < acked_slots; j++) {
 156                 if ((i + j) >= dev->ishtp_dma_num_slots ||
 157                                         !dev->ishtp_dma_tx_map[i+j]) {
 158                         /* no such slot, or memory is already free */
 159                         spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
 160                         dev_err(dev->devc, "Bad DMA Tx ack address\n");
 161                         return;
 162                 }
 163                 dev->ishtp_dma_tx_map[i+j] = 0;
 164         }
 165         spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
 166 }