From: Bharat Bhushan bharat.bhus...@freescale.com
The caam job rings (input/output job ring) are allocated using
dma_map_single(). These job rings can be visualized as the ring
buffers in which the jobs are en-queued/de-queued. The s/w enqueues
the jobs in input job ring which h/w dequeues and after processing
it copies the jobs in output job ring. Software then de-queues the
job from output ring. Using dma_map/unmap_single() is not preferred
way to allocate memory for this type of requirements because this
adds un-necessary complexity.
Example, if bounce buffer (SWIOTLB) will get used then to make any
change visible in this memory to other processing unit requires
dmap_unmap_single() or dma_sync_single_for_cpu/device(). The
dma_unmap_single() can not be used as this will free the bounce
buffer, this will require changing the job rings on running system
and I seriously doubt that it will be not possible or very complex
to implement. Also using dma_sync_single_for_cpu/device() will also
add unnecessary complexity.
The simple and preferred way is using dma_alloc_coherent() for these
type of memory requirements.
This resolves the Linux boot crash issue when swiotlb=force is set
in bootargs on systems which have memory more than 4G.
Signed-off-by: Bharat Bhushan bharat.bhus...@freescale.com
---
This patch is based on git://git.freescale.com/crypto/cryptodev.git master
which have Kim Phillip's [PATCH 00/20] crypto: caam - driver updates
patches, which are already sent uptream.
drivers/crypto/caam/jr.c | 45 +
1 files changed, 9 insertions(+), 36 deletions(-)
diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c
index 7074a1a..53c8c51 100644
--- a/drivers/crypto/caam/jr.c
+++ b/drivers/crypto/caam/jr.c
@@ -339,10 +339,11 @@ static int caam_jr_init(struct device *dev)
if (error)
return error;
- jrp-inpring = kzalloc(sizeof(dma_addr_t) * JOBR_DEPTH,
- GFP_KERNEL | GFP_DMA);
- jrp-outring = kzalloc(sizeof(struct jr_outentry) *
- JOBR_DEPTH, GFP_KERNEL | GFP_DMA);
+ jrp-inpring = dma_alloc_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
+ inpbusaddr, GFP_KERNEL);
+
+ jrp-outring = dma_alloc_coherent(dev, sizeof(struct jr_outentry) *
+ JOBR_DEPTH, outbusaddr, GFP_KERNEL);
jrp-entinfo = kzalloc(sizeof(struct caam_jrentry_info) * JOBR_DEPTH,
GFP_KERNEL);
@@ -358,31 +359,6 @@ static int caam_jr_init(struct device *dev)
jrp-entinfo[i].desc_addr_dma = !0;
/* Setup rings */
- inpbusaddr = dma_map_single(dev, jrp-inpring,
- sizeof(dma_addr_t) * JOBR_DEPTH,
- DMA_BIDIRECTIONAL);
- if (dma_mapping_error(dev, inpbusaddr)) {
- dev_err(dev, caam_jr_init(): can't map input ring\n);
- kfree(jrp-inpring);
- kfree(jrp-outring);
- kfree(jrp-entinfo);
- return -EIO;
- }
-
- outbusaddr = dma_map_single(dev, jrp-outring,
- sizeof(struct jr_outentry) * JOBR_DEPTH,
- DMA_BIDIRECTIONAL);
- if (dma_mapping_error(dev, outbusaddr)) {
- dev_err(dev, caam_jr_init(): can't map output ring\n);
- dma_unmap_single(dev, inpbusaddr,
-sizeof(dma_addr_t) * JOBR_DEPTH,
-DMA_BIDIRECTIONAL);
- kfree(jrp-inpring);
- kfree(jrp-outring);
- kfree(jrp-entinfo);
- return -EIO;
- }
-
jrp-inp_ring_write_index = 0;
jrp-out_ring_read_index = 0;
jrp-head = 0;
@@ -426,13 +402,10 @@ int caam_jr_shutdown(struct device *dev)
/* Free rings */
inpbusaddr = rd_reg64(jrp-rregs-inpring_base);
outbusaddr = rd_reg64(jrp-rregs-outring_base);
- dma_unmap_single(dev, outbusaddr,
-sizeof(struct jr_outentry) * JOBR_DEPTH,
-DMA_BIDIRECTIONAL);
- dma_unmap_single(dev, inpbusaddr, sizeof(dma_addr_t) * JOBR_DEPTH,
-DMA_BIDIRECTIONAL);
- kfree(jrp-outring);
- kfree(jrp-inpring);
+ dma_free_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
+ jrp-inpring, inpbusaddr);
+ dma_free_coherent(dev, sizeof(struct jr_outentry) * JOBR_DEPTH,
+ jrp-outring, outbusaddr);
kfree(jrp-entinfo);
return ret;
--
1.7.0.4
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