With CONFIG_DEBUG_SG is enabled and when dma mode is used, below dump is seen,
------------[ cut here ]------------ kernel BUG at include/linux/scatterlist.h:140! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-00459-g9f087b9-dirty #7 Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) task: ffffffc036868000 ti: ffffffc036870000 task.ti: ffffffc036870000 PC is at qup_sg_set_buf.isra.13+0x138/0x154 LR is at qup_sg_set_buf.isra.13+0x50/0x154 pc : [<ffffffc0005a0ed8>] lr : [<ffffffc0005a0df0>] pstate: 60000145 sp : ffffffc0368735c0 x29: ffffffc0368735c0 x28: ffffffc036873752 x27: ffffffc035233018 x26: ffffffc000c4e000 x25: 0000000000000000 x24: 0000000000000004 x23: 0000000000000000 x22: ffffffc035233668 x21: ffffff80004e3000 x20: ffffffc0352e0018 x19: 0000004000000000 x18: 0000000000000028 x17: 0000000000000004 x16: ffffffc0017a39c8 x15: 0000000000001cdf x14: ffffffc0019929d8 x13: ffffffc0352e0018 x12: 0000000000000000 x11: 0000000000000001 x10: 0000000000000001 x9 : ffffffc0012b2d70 x8 : ffffff80004e3000 x7 : 0000000000000018 x6 : 0000000030000000 x5 : ffffffc00199f018 x4 : ffffffc035233018 x3 : 0000000000000004 x2 : 00000000c0000000 x1 : 0000000000000003 x0 : 0000000000000000 Process swapper/0 (pid: 1, stack limit = 0xffffffc036870020) Stack: (0xffffffc0368735c0 to 0xffffffc036874000) Change allocation of sg buffers from dma_coherent memory to kzalloc to fix the issue. Signed-off-by: Sricharan R <[email protected]> Reviewed-by: Andy Gross <[email protected]> --- drivers/i2c/busses/i2c-qup.c | 53 ++++++++++++++------------------------------ 1 file changed, 17 insertions(+), 36 deletions(-) diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c index 23eaabb..8620e99 100644 --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -585,8 +585,8 @@ static void qup_i2c_bam_cb(void *data) } static int qup_sg_set_buf(struct scatterlist *sg, void *buf, - struct qup_i2c_tag *tg, unsigned int buflen, - struct qup_i2c_dev *qup, int map, int dir) + unsigned int buflen, struct qup_i2c_dev *qup, + int dir) { int ret; @@ -595,9 +595,6 @@ static int qup_sg_set_buf(struct scatterlist *sg, void *buf, if (!ret) return -EINVAL; - if (!map) - sg_dma_address(sg) = tg->addr + ((u8 *)buf - tg->start); - return 0; } @@ -670,16 +667,15 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, /* scratch buf to read the start and len tags */ ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++], &qup->brx.tag.start[0], - &qup->brx.tag, - 2, qup, 0, 0); + 2, qup, DMA_FROM_DEVICE); if (ret) return ret; ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++], &msg->buf[limit * i], - NULL, tlen, qup, - 1, DMA_FROM_DEVICE); + tlen, qup, + DMA_FROM_DEVICE); if (ret) return ret; @@ -688,7 +684,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, } ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], &qup->start_tag.start[off], - &qup->start_tag, len, qup, 0, 0); + len, qup, DMA_TO_DEVICE); if (ret) return ret; @@ -696,8 +692,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, /* scratch buf to read the BAM EOT and FLUSH tags */ ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++], &qup->brx.tag.start[0], - &qup->brx.tag, 2, - qup, 0, 0); + 2, qup, DMA_FROM_DEVICE); if (ret) return ret; } else { @@ -709,17 +704,15 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, len = qup_i2c_set_tags(tags, qup, msg, 1); ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], - tags, - &qup->start_tag, len, - qup, 0, 0); + tags, len, + qup, DMA_TO_DEVICE); if (ret) return ret; tx_len += len; ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], &msg->buf[limit * i], - NULL, tlen, qup, 1, - DMA_TO_DEVICE); + tlen, qup, DMA_TO_DEVICE); if (ret) return ret; i++; @@ -738,8 +731,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, QUP_BAM_FLUSH_STOP; ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], &qup->btx.tag.start[0], - &qup->btx.tag, len, - qup, 0, 0); + len, qup, DMA_TO_DEVICE); if (ret) return ret; tx_nents += 1; @@ -1268,6 +1260,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, } } + idx = 0; + do { if (msgs[idx].len == 0) { ret = -EINVAL; @@ -1407,27 +1401,21 @@ static int qup_i2c_probe(struct platform_device *pdev) /* 2 tag bytes for each block + 5 for start, stop tags */ size = blocks * 2 + 5; - qup->dpool = dma_pool_create("qup_i2c-dma-pool", &pdev->dev, - size, 4, 0); - qup->start_tag.start = dma_pool_alloc(qup->dpool, GFP_KERNEL, - &qup->start_tag.addr); + qup->start_tag.start = devm_kzalloc(&pdev->dev, + size, GFP_KERNEL); if (!qup->start_tag.start) { ret = -ENOMEM; goto fail_dma; } - qup->brx.tag.start = dma_pool_alloc(qup->dpool, - GFP_KERNEL, - &qup->brx.tag.addr); + qup->brx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL); if (!qup->brx.tag.start) { ret = -ENOMEM; goto fail_dma; } - qup->btx.tag.start = dma_pool_alloc(qup->dpool, - GFP_KERNEL, - &qup->btx.tag.addr); + qup->btx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL); if (!qup->btx.tag.start) { ret = -ENOMEM; goto fail_dma; @@ -1566,13 +1554,6 @@ static int qup_i2c_remove(struct platform_device *pdev) struct qup_i2c_dev *qup = platform_get_drvdata(pdev); if (qup->is_dma) { - dma_pool_free(qup->dpool, qup->start_tag.start, - qup->start_tag.addr); - dma_pool_free(qup->dpool, qup->brx.tag.start, - qup->brx.tag.addr); - dma_pool_free(qup->dpool, qup->btx.tag.start, - qup->btx.tag.addr); - dma_pool_destroy(qup->dpool); dma_release_channel(qup->btx.dma); dma_release_channel(qup->brx.dma); } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
