From 4e9f8187aecb00d90ec385f5061c91549103a3cf Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Tue, 3 Oct 2017 10:52:58 +0530 Subject: dmaengine: bcm-sba-raid: Use only single mailbox channel Each mailbox channel used by Broadcom SBA RAID driver is a separate HW ring. Currently, Broadcom SBA RAID driver creates one DMA channel using one or more mailbox channels. When we are using more than one mailbox channels for a DMA channel, the sba_request are distributed evenly among multiple mailbox channels which results in sba_request being completed out-of-order. The above described out-of-order completion of sba_request breaks the dma_async_is_complete() API because it assumes DMA cookies are completed in orderly fashion. To ensure correct behaviour of dma_async_is_complete() API, this patch updates Broadcom SBA RAID driver to use only single mailbox channel. If additional mailbox channels are specified in DT then those will be ignored. Signed-off-by: Anup Patel Reviewed-by: Ray Jui Reviewed-by: Scott Branden Signed-off-by: Vinod Koul --- drivers/dma/bcm-sba-raid.c | 104 ++++++++++++--------------------------------- 1 file changed, 27 insertions(+), 77 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/bcm-sba-raid.c b/drivers/dma/bcm-sba-raid.c index 15c558508345..409da59d9315 100644 --- a/drivers/dma/bcm-sba-raid.c +++ b/drivers/dma/bcm-sba-raid.c @@ -25,11 +25,8 @@ * * The Broadcom SBA RAID driver does not require any register programming * except submitting request to SBA hardware device via mailbox channels. - * This driver implements a DMA device with one DMA channel using a set - * of mailbox channels provided by Broadcom SoC specific ring manager - * driver. To exploit parallelism (as described above), all DMA request - * coming to SBA RAID DMA channel are broken down to smaller requests - * and submitted to multiple mailbox channels in round-robin fashion. + * This driver implements a DMA device with one DMA channel using a single + * mailbox channel provided by Broadcom SoC specific ring manager driver. * For having more SBA DMA channels, we can create more SBA device nodes * in Broadcom SoC specific DTS based on number of hardware rings supported * by Broadcom SoC ring manager. @@ -85,6 +82,7 @@ #define SBA_CMD_GALOIS 0xe #define SBA_MAX_REQ_PER_MBOX_CHANNEL 8192 +#define SBA_MAX_MSG_SEND_PER_MBOX_CHANNEL 8 /* Driver helper macros */ #define to_sba_request(tx) \ @@ -142,9 +140,7 @@ struct sba_device { u32 max_cmds_pool_size; /* Maibox client and Mailbox channels */ struct mbox_client client; - int mchans_count; - atomic_t mchans_current; - struct mbox_chan **mchans; + struct mbox_chan *mchan; struct device *mbox_dev; /* DMA device and DMA channel */ struct dma_device dma_dev; @@ -200,14 +196,6 @@ static inline u32 __pure sba_cmd_pq_c_mdata(u32 d, u32 b1, u32 b0) /* ====== General helper routines ===== */ -static void sba_peek_mchans(struct sba_device *sba) -{ - int mchan_idx; - - for (mchan_idx = 0; mchan_idx < sba->mchans_count; mchan_idx++) - mbox_client_peek_data(sba->mchans[mchan_idx]); -} - static struct sba_request *sba_alloc_request(struct sba_device *sba) { bool found = false; @@ -231,7 +219,7 @@ static struct sba_request *sba_alloc_request(struct sba_device *sba) * would have completed which will create more * room for new requests. */ - sba_peek_mchans(sba); + mbox_client_peek_data(sba->mchan); return NULL; } @@ -369,15 +357,11 @@ static void sba_cleanup_pending_requests(struct sba_device *sba) static int sba_send_mbox_request(struct sba_device *sba, struct sba_request *req) { - int mchans_idx, ret = 0; - - /* Select mailbox channel in round-robin fashion */ - mchans_idx = atomic_inc_return(&sba->mchans_current); - mchans_idx = mchans_idx % sba->mchans_count; + int ret = 0; /* Send message for the request */ req->msg.error = 0; - ret = mbox_send_message(sba->mchans[mchans_idx], &req->msg); + ret = mbox_send_message(sba->mchan, &req->msg); if (ret < 0) { dev_err(sba->dev, "send message failed with error %d", ret); return ret; @@ -390,7 +374,7 @@ static int sba_send_mbox_request(struct sba_device *sba, } /* Signal txdone for mailbox channel */ - mbox_client_txdone(sba->mchans[mchans_idx], ret); + mbox_client_txdone(sba->mchan, ret); return ret; } @@ -402,13 +386,8 @@ static void _sba_process_pending_requests(struct sba_device *sba) u32 count; struct sba_request *req; - /* - * Process few pending requests - * - * For now, we process ( * 8) - * number of requests at a time. - */ - count = sba->mchans_count * 8; + /* Process few pending requests */ + count = SBA_MAX_MSG_SEND_PER_MBOX_CHANNEL; while (!list_empty(&sba->reqs_pending_list) && count) { /* Get the first pending request */ req = list_first_entry(&sba->reqs_pending_list, @@ -572,7 +551,7 @@ static enum dma_status sba_tx_status(struct dma_chan *dchan, if (ret == DMA_COMPLETE) return ret; - sba_peek_mchans(sba); + mbox_client_peek_data(sba->mchan); return dma_cookie_status(dchan, cookie, txstate); } @@ -1639,7 +1618,7 @@ static int sba_async_register(struct sba_device *sba) static int sba_probe(struct platform_device *pdev) { - int i, ret = 0, mchans_count; + int ret = 0; struct sba_device *sba; struct platform_device *mbox_pdev; struct of_phandle_args args; @@ -1652,12 +1631,11 @@ static int sba_probe(struct platform_device *pdev) sba->dev = &pdev->dev; platform_set_drvdata(pdev, sba); - /* Number of channels equals number of mailbox channels */ + /* Number of mailbox channels should be atleast 1 */ ret = of_count_phandle_with_args(pdev->dev.of_node, "mboxes", "#mbox-cells"); if (ret <= 0) return -ENODEV; - mchans_count = ret; /* Determine SBA version from DT compatible string */ if (of_device_is_compatible(sba->dev->of_node, "brcm,iproc-sba")) @@ -1690,7 +1668,7 @@ static int sba_probe(struct platform_device *pdev) default: return -EINVAL; } - sba->max_req = SBA_MAX_REQ_PER_MBOX_CHANNEL * mchans_count; + sba->max_req = SBA_MAX_REQ_PER_MBOX_CHANNEL; sba->max_cmd_per_req = sba->max_pq_srcs + 3; sba->max_xor_srcs = sba->max_cmd_per_req - 1; sba->max_resp_pool_size = sba->max_req * sba->hw_resp_size; @@ -1704,55 +1682,30 @@ static int sba_probe(struct platform_device *pdev) sba->client.knows_txdone = true; sba->client.tx_tout = 0; - /* Allocate mailbox channel array */ - sba->mchans = devm_kcalloc(&pdev->dev, mchans_count, - sizeof(*sba->mchans), GFP_KERNEL); - if (!sba->mchans) - return -ENOMEM; - - /* Request mailbox channels */ - sba->mchans_count = 0; - for (i = 0; i < mchans_count; i++) { - sba->mchans[i] = mbox_request_channel(&sba->client, i); - if (IS_ERR(sba->mchans[i])) { - ret = PTR_ERR(sba->mchans[i]); - goto fail_free_mchans; - } - sba->mchans_count++; + /* Request mailbox channel */ + sba->mchan = mbox_request_channel(&sba->client, 0); + if (IS_ERR(sba->mchan)) { + ret = PTR_ERR(sba->mchan); + goto fail_free_mchan; } - atomic_set(&sba->mchans_current, 0); /* Find-out underlying mailbox device */ ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes", "#mbox-cells", 0, &args); if (ret) - goto fail_free_mchans; + goto fail_free_mchan; mbox_pdev = of_find_device_by_node(args.np); of_node_put(args.np); if (!mbox_pdev) { ret = -ENODEV; - goto fail_free_mchans; + goto fail_free_mchan; } sba->mbox_dev = &mbox_pdev->dev; - /* All mailbox channels should be of same ring manager device */ - for (i = 1; i < mchans_count; i++) { - ret = of_parse_phandle_with_args(pdev->dev.of_node, - "mboxes", "#mbox-cells", i, &args); - if (ret) - goto fail_free_mchans; - mbox_pdev = of_find_device_by_node(args.np); - of_node_put(args.np); - if (sba->mbox_dev != &mbox_pdev->dev) { - ret = -EINVAL; - goto fail_free_mchans; - } - } - /* Prealloc channel resource */ ret = sba_prealloc_channel_resources(sba); if (ret) - goto fail_free_mchans; + goto fail_free_mchan; /* Check availability of debugfs */ if (!debugfs_initialized()) @@ -1779,24 +1732,22 @@ skip_debugfs: goto fail_free_resources; /* Print device info */ - dev_info(sba->dev, "%s using SBAv%d and %d mailbox channels", + dev_info(sba->dev, "%s using SBAv%d mailbox channel from %s", dma_chan_name(&sba->dma_chan), sba->ver+1, - sba->mchans_count); + dev_name(sba->mbox_dev)); return 0; fail_free_resources: debugfs_remove_recursive(sba->root); sba_freeup_channel_resources(sba); -fail_free_mchans: - for (i = 0; i < sba->mchans_count; i++) - mbox_free_channel(sba->mchans[i]); +fail_free_mchan: + mbox_free_channel(sba->mchan); return ret; } static int sba_remove(struct platform_device *pdev) { - int i; struct sba_device *sba = platform_get_drvdata(pdev); dma_async_device_unregister(&sba->dma_dev); @@ -1805,8 +1756,7 @@ static int sba_remove(struct platform_device *pdev) sba_freeup_channel_resources(sba); - for (i = 0; i < sba->mchans_count; i++) - mbox_free_channel(sba->mchans[i]); + mbox_free_channel(sba->mchan); return 0; } -- cgit v1.2.3