[PATCH v4 2/4] crypto: mxs-dcp - Add support for dcp clk

From: Leonard Crestez
Date: Wed Oct 17 2018 - 08:38:09 EST


On 6ull and 6sll the DCP block has a clock which needs to be explicitly
enabled.

Add minimal handling for this at probe/remove time.

Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
---
drivers/crypto/mxs-dcp.c | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
index 4e6ff32f8a7e..a2105cf33abb 100644
--- a/drivers/crypto/mxs-dcp.c
+++ b/drivers/crypto/mxs-dcp.c
@@ -18,10 +18,11 @@
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/stmp_device.h>
+#include <linux/clk.h>

#include <crypto/aes.h>
#include <crypto/sha.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
@@ -80,10 +81,11 @@ struct dcp {

struct completion completion[DCP_MAX_CHANS];
spinlock_t lock[DCP_MAX_CHANS];
struct task_struct *thread[DCP_MAX_CHANS];
struct crypto_queue queue[DCP_MAX_CHANS];
+ struct clk *dcp_clk;
};

enum dcp_chan {
DCP_CHAN_HASH_SHA = 0,
DCP_CHAN_CRYPTO = 2,
@@ -1051,15 +1053,28 @@ static int mxs_dcp_probe(struct platform_device *pdev)
return -ENOMEM;

/* Re-align the structure so it fits the DCP constraints. */
sdcp->coh = PTR_ALIGN(sdcp->coh, DCP_ALIGNMENT);

- /* Restart the DCP block. */
- ret = stmp_reset_block(sdcp->base);
+ /* DCP clock is optional, only used on some SOCs */
+ sdcp->dcp_clk = devm_clk_get(dev, "dcp");
+ if (IS_ERR(sdcp->dcp_clk)) {
+ if (sdcp->dcp_clk != ERR_PTR(-ENOENT))
+ return PTR_ERR(sdcp->dcp_clk);
+ sdcp->dcp_clk = NULL;
+ }
+ ret = clk_prepare_enable(sdcp->dcp_clk);
if (ret)
return ret;

+ /* Restart the DCP block. */
+ ret = stmp_reset_block(sdcp->base);
+ if (ret) {
+ dev_err(dev, "Failed reset\n");
+ goto err_disable_unprepare_clk;
+ }
+
/* Initialize control register. */
writel(MXS_DCP_CTRL_GATHER_RESIDUAL_WRITES |
MXS_DCP_CTRL_ENABLE_CONTEXT_CACHING | 0xf,
sdcp->base + MXS_DCP_CTRL);

@@ -1092,11 +1107,12 @@ static int mxs_dcp_probe(struct platform_device *pdev)
/* Create the SHA and AES handler threads. */
sdcp->thread[DCP_CHAN_HASH_SHA] = kthread_run(dcp_chan_thread_sha,
NULL, "mxs_dcp_chan/sha");
if (IS_ERR(sdcp->thread[DCP_CHAN_HASH_SHA])) {
dev_err(dev, "Error starting SHA thread!\n");
- return PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
+ ret = PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
+ goto err_disable_unprepare_clk;
}

sdcp->thread[DCP_CHAN_CRYPTO] = kthread_run(dcp_chan_thread_aes,
NULL, "mxs_dcp_chan/aes");
if (IS_ERR(sdcp->thread[DCP_CHAN_CRYPTO])) {
@@ -1149,10 +1165,14 @@ static int mxs_dcp_probe(struct platform_device *pdev)
err_destroy_aes_thread:
kthread_stop(sdcp->thread[DCP_CHAN_CRYPTO]);

err_destroy_sha_thread:
kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
+
+err_disable_unprepare_clk:
+ clk_disable_unprepare(sdcp->dcp_clk);
+
return ret;
}

static int mxs_dcp_remove(struct platform_device *pdev)
{
@@ -1168,10 +1188,12 @@ static int mxs_dcp_remove(struct platform_device *pdev)
crypto_unregister_algs(dcp_aes_algs, ARRAY_SIZE(dcp_aes_algs));

kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
kthread_stop(sdcp->thread[DCP_CHAN_CRYPTO]);

+ clk_disable_unprepare(sdcp->dcp_clk);
+
platform_set_drvdata(pdev, NULL);

global_sdcp = NULL;

return 0;
--
2.17.1