1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * i2c-stm32.c 4 * 5 * Copyright (C) M'boumba Cedric Madianga 2017 6 * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com> 7 */ 8 9 #include "i2c-stm32.h" 10 11 /* Functions for DMA support */ 12 struct stm32_i2c_dma *stm32_i2c_dma_request(struct device *dev, 13 dma_addr_t phy_addr, 14 u32 txdr_offset, 15 u32 rxdr_offset) 16 { 17 struct stm32_i2c_dma *dma; 18 struct dma_slave_config dma_sconfig; 19 int ret; 20 21 dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); 22 if (!dma) 23 return ERR_PTR(-ENOMEM); 24 25 /* Request and configure I2C TX dma channel */ 26 dma->chan_tx = dma_request_chan(dev, "tx"); 27 if (IS_ERR(dma->chan_tx)) { 28 ret = PTR_ERR(dma->chan_tx); 29 if (ret != -ENODEV) 30 dev_err_probe(dev, ret, "can't request DMA tx channel\n"); 31 32 goto fail_al; 33 } 34 35 memset(&dma_sconfig, 0, sizeof(dma_sconfig)); 36 dma_sconfig.dst_addr = phy_addr + txdr_offset; 37 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 38 dma_sconfig.dst_maxburst = 1; 39 dma_sconfig.direction = DMA_MEM_TO_DEV; 40 ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig); 41 if (ret < 0) { 42 dev_err(dev, "can't configure tx channel\n"); 43 goto fail_tx; 44 } 45 46 /* Request and configure I2C RX dma channel */ 47 dma->chan_rx = dma_request_chan(dev, "rx"); 48 if (IS_ERR(dma->chan_rx)) { 49 ret = PTR_ERR(dma->chan_rx); 50 if (ret != -ENODEV) 51 dev_err_probe(dev, ret, "can't request DMA rx channel\n"); 52 53 goto fail_tx; 54 } 55 56 memset(&dma_sconfig, 0, sizeof(dma_sconfig)); 57 dma_sconfig.src_addr = phy_addr + rxdr_offset; 58 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 59 dma_sconfig.src_maxburst = 1; 60 dma_sconfig.direction = DMA_DEV_TO_MEM; 61 ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig); 62 if (ret < 0) { 63 dev_err(dev, "can't configure rx channel\n"); 64 goto fail_rx; 65 } 66 67 init_completion(&dma->dma_complete); 68 69 dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", 70 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); 71 72 return dma; 73 74 fail_rx: 75 dma_release_channel(dma->chan_rx); 76 fail_tx: 77 dma_release_channel(dma->chan_tx); 78 fail_al: 79 devm_kfree(dev, dma); 80 81 return ERR_PTR(ret); 82 } 83 84 void stm32_i2c_dma_free(struct stm32_i2c_dma *dma) 85 { 86 dma->dma_buf = 0; 87 dma->dma_len = 0; 88 89 dma_release_channel(dma->chan_tx); 90 dma->chan_tx = NULL; 91 92 dma_release_channel(dma->chan_rx); 93 dma->chan_rx = NULL; 94 95 dma->chan_using = NULL; 96 } 97 98 int stm32_i2c_prep_dma_xfer(struct device *dev, struct stm32_i2c_dma *dma, 99 bool rd_wr, u32 len, u8 *buf, 100 dma_async_tx_callback callback, 101 void *dma_async_param) 102 { 103 struct dma_async_tx_descriptor *txdesc; 104 int ret; 105 106 if (rd_wr) { 107 dma->chan_using = dma->chan_rx; 108 dma->dma_transfer_dir = DMA_DEV_TO_MEM; 109 dma->dma_data_dir = DMA_FROM_DEVICE; 110 } else { 111 dma->chan_using = dma->chan_tx; 112 dma->dma_transfer_dir = DMA_MEM_TO_DEV; 113 dma->dma_data_dir = DMA_TO_DEVICE; 114 } 115 116 dma->dma_len = len; 117 118 dma->dma_buf = dma_map_single(dev, buf, dma->dma_len, 119 dma->dma_data_dir); 120 if (dma_mapping_error(dev, dma->dma_buf)) { 121 dev_err(dev, "DMA mapping failed\n"); 122 return -EINVAL; 123 } 124 125 txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf, 126 dma->dma_len, 127 dma->dma_transfer_dir, 128 DMA_PREP_INTERRUPT); 129 if (!txdesc) { 130 dev_err(dev, "Not able to get desc for DMA xfer\n"); 131 ret = -EINVAL; 132 goto err; 133 } 134 135 reinit_completion(&dma->dma_complete); 136 137 txdesc->callback = callback; 138 txdesc->callback_param = dma_async_param; 139 ret = dma_submit_error(dmaengine_submit(txdesc)); 140 if (ret < 0) { 141 dev_err(dev, "DMA submit failed\n"); 142 goto err; 143 } 144 145 dma_async_issue_pending(dma->chan_using); 146 147 return 0; 148 149 err: 150 dma_unmap_single(dev, dma->dma_buf, dma->dma_len, 151 dma->dma_data_dir); 152 return ret; 153 } 154