crypto: sun4i-ss - enable pm_runtime

This patch enables power management on the Security System.
sun4i-ss now depends on PM because it simplify code and prevent some ifdef.
But this is not a problem since arch maintainer want ARCH_SUNXI to
depend on PM in the future.

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/Kconfig

@@ -660,6 +660,7 @@ config CRYPTO_DEV_IMGTEC_HASH
 config CRYPTO_DEV_SUN4I_SS
 	tristate "Support for Allwinner Security System cryptographic accelerator"
 	depends on ARCH_SUNXI && !64BIT
+	depends on PM
 	select CRYPTO_MD5
 	select CRYPTO_SHA1
 	select CRYPTO_AES

drivers/crypto/sunxi-ss/sun4i-ss-cipher.c

@@ -480,6 +480,7 @@ int sun4i_ss_cipher_init(struct crypto_tfm *tfm)
 	struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
 	struct sun4i_ss_alg_template *algt;
 	const char *name = crypto_tfm_alg_name(tfm);
+	int err;
 
 	memset(op, 0, sizeof(struct sun4i_tfm_ctx));
 
@@ -497,13 +498,22 @@ int sun4i_ss_cipher_init(struct crypto_tfm *tfm)
 		return PTR_ERR(op->fallback_tfm);
 	}
 
+	err = pm_runtime_get_sync(op->ss->dev);
+	if (err < 0)
+		goto error_pm;
+
 	return 0;
+error_pm:
+	crypto_free_sync_skcipher(op->fallback_tfm);
+	return err;
 }
 
 void sun4i_ss_cipher_exit(struct crypto_tfm *tfm)
 {
 	struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
+
 	crypto_free_sync_skcipher(op->fallback_tfm);
+	pm_runtime_put(op->ss->dev);
 }
 
 /* check and set the AES key, prepare the mode to be used */

drivers/crypto/sunxi-ss/sun4i-ss-core.c

@@ -44,7 +44,8 @@ static struct sun4i_ss_alg_template ss_algs[] = {
 				.cra_blocksize = MD5_HMAC_BLOCK_SIZE,
 				.cra_ctxsize = sizeof(struct sun4i_req_ctx),
 				.cra_module = THIS_MODULE,
-				.cra_init = sun4i_hash_crainit
+				.cra_init = sun4i_hash_crainit,
+				.cra_exit = sun4i_hash_craexit,
 			}
 		}
 	}
@@ -70,7 +71,8 @@ static struct sun4i_ss_alg_template ss_algs[] = {
 				.cra_blocksize = SHA1_BLOCK_SIZE,
 				.cra_ctxsize = sizeof(struct sun4i_req_ctx),
 				.cra_module = THIS_MODULE,
-				.cra_init = sun4i_hash_crainit
+				.cra_init = sun4i_hash_crainit,
+				.cra_exit = sun4i_hash_craexit,
 			}
 		}
 	}
@@ -223,17 +225,26 @@ static struct sun4i_ss_alg_template ss_algs[] = {
 #endif
 };
 
-static void sun4i_ss_disable(struct sun4i_ss_ctx *ss)
+/*
+ * Power management strategy: The device is suspended unless a TFM exists for
+ * one of the algorithms proposed by this driver.
+ */
+static int sun4i_ss_pm_suspend(struct device *dev)
 {
+	struct sun4i_ss_ctx *ss = dev_get_drvdata(dev);
+
 	if (ss->reset)
 		reset_control_assert(ss->reset);
 
 	clk_disable_unprepare(ss->ssclk);
 	clk_disable_unprepare(ss->busclk);
+	return 0;
 }
 
-static int sun4i_ss_enable(struct sun4i_ss_ctx *ss)
+static int sun4i_ss_pm_resume(struct device *dev)
 {
+	struct sun4i_ss_ctx *ss = dev_get_drvdata(dev);
+
 	int err;
 
 	err = clk_prepare_enable(ss->busclk);
@@ -258,10 +269,38 @@ static int sun4i_ss_enable(struct sun4i_ss_ctx *ss)
 
 	return err;
 err_enable:
-	sun4i_ss_disable(ss);
+	sun4i_ss_pm_suspend(dev);
 	return err;
 }
 
+const struct dev_pm_ops sun4i_ss_pm_ops = {
+	SET_RUNTIME_PM_OPS(sun4i_ss_pm_suspend, sun4i_ss_pm_resume, NULL)
+};
+
+/*
+ * When power management is enabled, this function enables the PM and set the
+ * device as suspended
+ * When power management is disabled, this function just enables the device
+ */
+static int sun4i_ss_pm_init(struct sun4i_ss_ctx *ss)
+{
+	int err;
+
+	pm_runtime_use_autosuspend(ss->dev);
+	pm_runtime_set_autosuspend_delay(ss->dev, 2000);
+
+	err = pm_runtime_set_suspended(ss->dev);
+	if (err)
+		return err;
+	pm_runtime_enable(ss->dev);
+	return err;
+}
+
+static void sun4i_ss_pm_exit(struct sun4i_ss_ctx *ss)
+{
+	pm_runtime_disable(ss->dev);
+}
+
 static int sun4i_ss_probe(struct platform_device *pdev)
 {
 	u32 v;
@@ -308,10 +347,6 @@ static int sun4i_ss_probe(struct platform_device *pdev)
 		ss->reset = NULL;
 	}
 
-	err = sun4i_ss_enable(ss);
-	if (err)
-		goto error_enable;
-
 	/*
 	 * Check that clock have the correct rates given in the datasheet
 	 * Try to set the clock to the maximum allowed
@@ -319,7 +354,7 @@ static int sun4i_ss_probe(struct platform_device *pdev)
 	err = clk_set_rate(ss->ssclk, cr_mod);
 	if (err) {
 		dev_err(&pdev->dev, "Cannot set clock rate to ssclk\n");
-		goto error_enable;
+		return err;
 	}
 
 	/*
@@ -347,12 +382,26 @@ static int sun4i_ss_probe(struct platform_device *pdev)
 		dev_warn(&pdev->dev, "Clock ss is at %lu (%lu MHz) (must be <= %lu)\n",
 			 cr, cr / 1000000, cr_mod);
 
+	ss->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ss);
+
+	spin_lock_init(&ss->slock);
+
+	err = sun4i_ss_pm_init(ss);
+	if (err)
+		return err;
+
 	/*
 	 * Datasheet named it "Die Bonding ID"
 	 * I expect to be a sort of Security System Revision number.
 	 * Since the A80 seems to have an other version of SS
 	 * this info could be useful
 	 */
+
+	err = pm_runtime_get_sync(ss->dev);
+	if (err < 0)
+		goto error_pm;
+
 	writel(SS_ENABLED, ss->base + SS_CTL);
 	v = readl(ss->base + SS_CTL);
 	v >>= 16;
@@ -360,9 +409,7 @@ static int sun4i_ss_probe(struct platform_device *pdev)
 	dev_info(&pdev->dev, "Die ID %d\n", v);
 	writel(0, ss->base + SS_CTL);
 
-	ss->dev = &pdev->dev;
-
-	spin_lock_init(&ss->slock);
+	pm_runtime_put_sync(ss->dev);
 
 	for (i = 0; i < ARRAY_SIZE(ss_algs); i++) {
 		ss_algs[i].ss = ss;
@@ -392,7 +439,6 @@ static int sun4i_ss_probe(struct platform_device *pdev)
 			break;
 		}
 	}
-	platform_set_drvdata(pdev, ss);
 	return 0;
 error_alg:
 	i--;
@@ -409,8 +455,8 @@ error_alg:
 			break;
 		}
 	}
-error_enable:
-	sun4i_ss_disable(ss);
+error_pm:
+	sun4i_ss_pm_exit(ss);
 	return err;
 }
 
@@ -433,8 +479,7 @@ static int sun4i_ss_remove(struct platform_device *pdev)
 		}
 	}
 
-	writel(0, ss->base + SS_CTL);
-	sun4i_ss_disable(ss);
+	sun4i_ss_pm_exit(ss);
 	return 0;
 }
 
@@ -449,6 +494,7 @@ static struct platform_driver sun4i_ss_driver = {
 	.remove         = sun4i_ss_remove,
 	.driver         = {
 		.name           = "sun4i-ss",
+		.pm		= &sun4i_ss_pm_ops,
 		.of_match_table	= a20ss_crypto_of_match_table,
 	},
 };

drivers/crypto/sunxi-ss/sun4i-ss-hash.c

@@ -19,17 +19,29 @@ int sun4i_hash_crainit(struct crypto_tfm *tfm)
 	struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
 	struct ahash_alg *alg = __crypto_ahash_alg(tfm->__crt_alg);
 	struct sun4i_ss_alg_template *algt;
+	int err;
 
 	memset(op, 0, sizeof(struct sun4i_tfm_ctx));
 
 	algt = container_of(alg, struct sun4i_ss_alg_template, alg.hash);
 	op->ss = algt->ss;
 
+	err = pm_runtime_get_sync(op->ss->dev);
+	if (err < 0)
+		return err;
+
 	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
 				 sizeof(struct sun4i_req_ctx));
 	return 0;
 }
 
+void sun4i_hash_craexit(struct crypto_tfm *tfm)
+{
+	struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
+
+	pm_runtime_put(op->ss->dev);
+}
+
 /* sun4i_hash_init: initialize request context */
 int sun4i_hash_init(struct ahash_request *areq)
 {

drivers/crypto/sunxi-ss/sun4i-ss-prng.c

@@ -17,7 +17,7 @@ int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
 {
 	struct sun4i_ss_alg_template *algt;
 	struct rng_alg *alg = crypto_rng_alg(tfm);
-	int i;
+	int i, err;
 	u32 v;
 	u32 *data = (u32 *)dst;
 	const u32 mode = SS_OP_PRNG | SS_PRNG_CONTINUE | SS_ENABLED;
@@ -28,6 +28,10 @@ int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
 	algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
 	ss = algt->ss;
 
+	err = pm_runtime_get_sync(ss->dev);
+	if (err < 0)
+		return err;
+
 	spin_lock_bh(&ss->slock);
 
 	writel(mode, ss->base + SS_CTL);
@@ -52,5 +56,8 @@ int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
 
 	writel(0, ss->base + SS_CTL);
 	spin_unlock_bh(&ss->slock);
+
+	pm_runtime_put(ss->dev);
+
 	return 0;
 }

drivers/crypto/sunxi-ss/sun4i-ss.h

@@ -22,6 +22,7 @@
 #include <linux/scatterlist.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
+#include <linux/pm_runtime.h>
 #include <crypto/md5.h>
 #include <crypto/skcipher.h>
 #include <crypto/sha.h>
@@ -177,6 +178,7 @@ struct sun4i_req_ctx {
 };
 
 int sun4i_hash_crainit(struct crypto_tfm *tfm);
+void sun4i_hash_craexit(struct crypto_tfm *tfm);
 int sun4i_hash_init(struct ahash_request *areq);
 int sun4i_hash_update(struct ahash_request *areq);
 int sun4i_hash_final(struct ahash_request *areq);