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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * i2c-stm32.c4 *5 * Copyright (C) M'boumba Cedric Madianga 20176 * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>7 */8 9#include "i2c-stm32.h"10 11/* Functions for DMA support */12struct 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 ret = dev_err_probe(dev, ret,31 "can't request DMA tx channel\n");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 ret = dev_err_probe(dev, ret,52 "can't request DMA rx channel\n");53 54 goto fail_tx;55 }56 57 memset(&dma_sconfig, 0, sizeof(dma_sconfig));58 dma_sconfig.src_addr = phy_addr + rxdr_offset;59 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;60 dma_sconfig.src_maxburst = 1;61 dma_sconfig.direction = DMA_DEV_TO_MEM;62 ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig);63 if (ret < 0) {64 dev_err(dev, "can't configure rx channel\n");65 goto fail_rx;66 }67 68 init_completion(&dma->dma_complete);69 70 dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n",71 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));72 73 return dma;74 75fail_rx:76 dma_release_channel(dma->chan_rx);77fail_tx:78 dma_release_channel(dma->chan_tx);79fail_al:80 devm_kfree(dev, dma);81 82 return ERR_PTR(ret);83}84 85void stm32_i2c_dma_free(struct stm32_i2c_dma *dma)86{87 dma->dma_buf = 0;88 dma->dma_len = 0;89 90 dma_release_channel(dma->chan_tx);91 dma->chan_tx = NULL;92 93 dma_release_channel(dma->chan_rx);94 dma->chan_rx = NULL;95 96 dma->chan_using = NULL;97}98 99int stm32_i2c_prep_dma_xfer(struct device *dev, struct stm32_i2c_dma *dma,100 bool rd_wr, u32 len, u8 *buf,101 dma_async_tx_callback callback,102 void *dma_async_param)103{104 struct dma_async_tx_descriptor *txdesc;105 struct device *chan_dev;106 int ret;107 108 if (rd_wr) {109 dma->chan_using = dma->chan_rx;110 dma->dma_transfer_dir = DMA_DEV_TO_MEM;111 dma->dma_data_dir = DMA_FROM_DEVICE;112 } else {113 dma->chan_using = dma->chan_tx;114 dma->dma_transfer_dir = DMA_MEM_TO_DEV;115 dma->dma_data_dir = DMA_TO_DEVICE;116 }117 118 dma->dma_len = len;119 chan_dev = dma->chan_using->device->dev;120 121 dma->dma_buf = dma_map_single(chan_dev, buf, dma->dma_len,122 dma->dma_data_dir);123 if (dma_mapping_error(chan_dev, dma->dma_buf)) {124 dev_err(dev, "DMA mapping failed\n");125 return -EINVAL;126 }127 128 txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf,129 dma->dma_len,130 dma->dma_transfer_dir,131 DMA_PREP_INTERRUPT);132 if (!txdesc) {133 dev_err(dev, "Not able to get desc for DMA xfer\n");134 ret = -EINVAL;135 goto err;136 }137 138 reinit_completion(&dma->dma_complete);139 140 txdesc->callback = callback;141 txdesc->callback_param = dma_async_param;142 ret = dma_submit_error(dmaengine_submit(txdesc));143 if (ret < 0) {144 dev_err(dev, "DMA submit failed\n");145 goto err;146 }147 148 dma_async_issue_pending(dma->chan_using);149 150 return 0;151 152err:153 dma_unmap_single(chan_dev, dma->dma_buf, dma->dma_len,154 dma->dma_data_dir);155 return ret;156}157