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 dev_dbg(dev, "can't request DMA tx channel\n"); 29 ret = PTR_ERR(dma->chan_tx); 30 goto fail_al; 31 } 32 33 memset(&dma_sconfig, 0, sizeof(dma_sconfig)); 34 dma_sconfig.dst_addr = phy_addr + txdr_offset; 35 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 36 dma_sconfig.dst_maxburst = 1; 37 dma_sconfig.direction = DMA_MEM_TO_DEV; 38 ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig); 39 if (ret < 0) { 40 dev_err(dev, "can't configure tx channel\n"); 41 goto fail_tx; 42 } 43 44 /* Request and configure I2C RX dma channel */ 45 dma->chan_rx = dma_request_chan(dev, "rx"); 46 if (IS_ERR(dma->chan_rx)) { 47 dev_err(dev, "can't request DMA rx channel\n"); 48 ret = PTR_ERR(dma->chan_rx); 49 goto fail_tx; 50 } 51 52 memset(&dma_sconfig, 0, sizeof(dma_sconfig)); 53 dma_sconfig.src_addr = phy_addr + rxdr_offset; 54 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 55 dma_sconfig.src_maxburst = 1; 56 dma_sconfig.direction = DMA_DEV_TO_MEM; 57 ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig); 58 if (ret < 0) { 59 dev_err(dev, "can't configure rx channel\n"); 60 goto fail_rx; 61 } 62 63 init_completion(&dma->dma_complete); 64 65 dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", 66 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); 67 68 return dma; 69 70 fail_rx: 71 dma_release_channel(dma->chan_rx); 72 fail_tx: 73 dma_release_channel(dma->chan_tx); 74 fail_al: 75 devm_kfree(dev, dma); 76 dev_info(dev, "can't use DMA\n"); 77 78 return ERR_PTR(ret); 79 } 80 81 void stm32_i2c_dma_free(struct stm32_i2c_dma *dma) 82 { 83 dma->dma_buf = 0; 84 dma->dma_len = 0; 85 86 dma_release_channel(dma->chan_tx); 87 dma->chan_tx = NULL; 88 89 dma_release_channel(dma->chan_rx); 90 dma->chan_rx = NULL; 91 92 dma->chan_using = NULL; 93 } 94 95 int stm32_i2c_prep_dma_xfer(struct device *dev, struct stm32_i2c_dma *dma, 96 bool rd_wr, u32 len, u8 *buf, 97 dma_async_tx_callback callback, 98 void *dma_async_param) 99 { 100 struct dma_async_tx_descriptor *txdesc; 101 struct device *chan_dev; 102 int ret; 103 104 if (rd_wr) { 105 dma->chan_using = dma->chan_rx; 106 dma->dma_transfer_dir = DMA_DEV_TO_MEM; 107 dma->dma_data_dir = DMA_FROM_DEVICE; 108 } else { 109 dma->chan_using = dma->chan_tx; 110 dma->dma_transfer_dir = DMA_MEM_TO_DEV; 111 dma->dma_data_dir = DMA_TO_DEVICE; 112 } 113 114 dma->dma_len = len; 115 chan_dev = dma->chan_using->device->dev; 116 117 dma->dma_buf = dma_map_single(chan_dev, buf, dma->dma_len, 118 dma->dma_data_dir); 119 if (dma_mapping_error(chan_dev, dma->dma_buf)) { 120 dev_err(dev, "DMA mapping failed\n"); 121 return -EINVAL; 122 } 123 124 txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf, 125 dma->dma_len, 126 dma->dma_transfer_dir, 127 DMA_PREP_INTERRUPT); 128 if (!txdesc) { 129 dev_err(dev, "Not able to get desc for DMA xfer\n"); 130 ret = -EINVAL; 131 goto err; 132 } 133 134 reinit_completion(&dma->dma_complete); 135 136 txdesc->callback = callback; 137 txdesc->callback_param = dma_async_param; 138 ret = dma_submit_error(dmaengine_submit(txdesc)); 139 if (ret < 0) { 140 dev_err(dev, "DMA submit failed\n"); 141 goto err; 142 } 143 144 dma_async_issue_pending(dma->chan_using); 145 146 return 0; 147 148 err: 149 dma_unmap_single(chan_dev, dma->dma_buf, dma->dma_len, 150 dma->dma_data_dir); 151 return ret; 152 } 153