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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 <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Anup Patel 2017-10-03 10:52:58 +05:30 committed by Vinod Koul
parent 5d74aa7f64
commit 4e9f8187ae
1 changed files with 27 additions and 77 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

104
drivers/dma/bcm-sba-raid.c
View File

@ -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 (<number_of_mailbox_channels> * 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;
}