crypto: tegra - Add Tegra Security Engine driver

Add support for Tegra Security Engine which can accelerate various
crypto algorithms. The Engine has two separate instances within for
AES and HASH algorithms respectively.

The driver registers two crypto engines - one for AES and another for
HASH algorithms and these operate independently and both uses the host1x
bus. Additionally, it provides  hardware-assisted key protection for up
to 15 symmetric keys which it can use for the cipher operations.
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

MAINTAINERS

@@ -21702,6 +21702,11 @@ M:	Prashant Gaikwad <pgaikwad@nvidia.com>
 S:	Supported
 F:	drivers/clk/tegra/
 
+TEGRA CRYPTO DRIVERS
+M:	Akhil R <akhilrajeev@nvidia.com>
+S:	Supported
+F:	drivers/crypto/tegra/*
+
 TEGRA DMA DRIVERS
 M:	Laxman Dewangan <ldewangan@nvidia.com>
 M:	Jon Hunter <jonathanh@nvidia.com>

drivers/crypto/Kconfig

@@ -660,6 +660,14 @@ config CRYPTO_DEV_ROCKCHIP_DEBUG
 	  This will create /sys/kernel/debug/rk3288_crypto/stats for displaying
 	  the number of requests per algorithm and other internal stats.
 
+config CRYPTO_DEV_TEGRA
+	tristate "Enable Tegra Security Engine"
+	depends on TEGRA_HOST1X
+	select CRYPTO_ENGINE
+
+	help
+	  Select this to enable Tegra Security Engine which accelerates various
+	  AES encryption/decryption and HASH algorithms.
 
 config CRYPTO_DEV_ZYNQMP_AES
 	tristate "Support for Xilinx ZynqMP AES hw accelerator"

drivers/crypto/Makefile

@@ -41,6 +41,7 @@ obj-$(CONFIG_CRYPTO_DEV_SAHARA) += sahara.o
 obj-$(CONFIG_CRYPTO_DEV_SL3516) += gemini/
 obj-y += stm32/
 obj-$(CONFIG_CRYPTO_DEV_TALITOS) += talitos.o
+obj-$(CONFIG_CRYPTO_DEV_TEGRA) += tegra/
 obj-$(CONFIG_CRYPTO_DEV_VIRTIO) += virtio/
 #obj-$(CONFIG_CRYPTO_DEV_VMX) += vmx/
 obj-$(CONFIG_CRYPTO_DEV_BCM_SPU) += bcm/

drivers/crypto/tegra/Makefile

+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
+tegra-se-objs := tegra-se-key.o tegra-se-main.o
+
+tegra-se-y += tegra-se-aes.o
+tegra-se-y += tegra-se-hash.o
+
+obj-$(CONFIG_CRYPTO_DEV_TEGRA) += tegra-se.o

drivers/crypto/tegra/tegra-se-key.c

+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+/*
+ * Crypto driver file to manage keys of NVIDIA Security Engine.
+ */
+
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <crypto/aes.h>
+
+#include "tegra-se.h"
+
+#define SE_KEY_FULL_MASK		GENMASK(SE_MAX_KEYSLOT, 0)
+
+/* Reserve keyslot 0, 14, 15 */
+#define SE_KEY_RSVD_MASK		(BIT(0) | BIT(14) | BIT(15))
+#define SE_KEY_VALID_MASK		(SE_KEY_FULL_MASK & ~SE_KEY_RSVD_MASK)
+
+/* Mutex lock to guard keyslots */
+static DEFINE_MUTEX(kslt_lock);
+
+/* Keyslot bitmask (0 = available, 1 = in use/not available) */
+static u16 tegra_se_keyslots = SE_KEY_RSVD_MASK;
+
+static u16 tegra_keyslot_alloc(void)
+{
+	u16 keyid;
+
+	mutex_lock(&kslt_lock);
+	/* Check if all key slots are full */
+	if (tegra_se_keyslots == GENMASK(SE_MAX_KEYSLOT, 0)) {
+		mutex_unlock(&kslt_lock);
+		return 0;
+	}
+
+	keyid = ffz(tegra_se_keyslots);
+	tegra_se_keyslots |= BIT(keyid);
+
+	mutex_unlock(&kslt_lock);
+
+	return keyid;
+}
+
+static void tegra_keyslot_free(u16 slot)
+{
+	mutex_lock(&kslt_lock);
+	tegra_se_keyslots &= ~(BIT(slot));
+	mutex_unlock(&kslt_lock);
+}
+
+static unsigned int tegra_key_prep_ins_cmd(struct tegra_se *se, u32 *cpuvaddr,
+					   const u32 *key, u32 keylen, u16 slot, u32 alg)
+{
+	int i = 0, j;
+
+	cpuvaddr[i++] = host1x_opcode_setpayload(1);
+	cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->op);
+	cpuvaddr[i++] = SE_AES_OP_WRSTALL | SE_AES_OP_DUMMY;
+
+	cpuvaddr[i++] = host1x_opcode_setpayload(1);
+	cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->manifest);
+	cpuvaddr[i++] = se->manifest(se->owner, alg, keylen);
+	cpuvaddr[i++] = host1x_opcode_setpayload(1);
+	cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->key_dst);
+
+	cpuvaddr[i++] = SE_AES_KEY_DST_INDEX(slot);
+
+	for (j = 0; j < keylen / 4; j++) {
+		/* Set key address */
+		cpuvaddr[i++] = host1x_opcode_setpayload(1);
+		cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->key_addr);
+		cpuvaddr[i++] = j;
+
+		/* Set key data */
+		cpuvaddr[i++] = host1x_opcode_setpayload(1);
+		cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->key_data);
+		cpuvaddr[i++] = key[j];
+	}
+
+	cpuvaddr[i++] = host1x_opcode_setpayload(1);
+	cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->config);
+	cpuvaddr[i++] = SE_CFG_INS;
+
+	cpuvaddr[i++] = host1x_opcode_setpayload(1);
+	cpuvaddr[i++] = se_host1x_opcode_incr_w(se->hw->regs->op);
+	cpuvaddr[i++] = SE_AES_OP_WRSTALL | SE_AES_OP_START |
+			SE_AES_OP_LASTBUF;
+
+	cpuvaddr[i++] = se_host1x_opcode_nonincr(host1x_uclass_incr_syncpt_r(), 1);
+	cpuvaddr[i++] = host1x_uclass_incr_syncpt_cond_f(1) |
+			host1x_uclass_incr_syncpt_indx_f(se->syncpt_id);
+
+	dev_dbg(se->dev, "key-slot %u key-manifest %#x\n",
+		slot, se->manifest(se->owner, alg, keylen));
+
+	return i;
+}
+
+static bool tegra_key_in_kslt(u32 keyid)
+{
+	bool ret;
+
+	if (keyid > SE_MAX_KEYSLOT)
+		return false;
+
+	mutex_lock(&kslt_lock);
+	ret = ((BIT(keyid) & SE_KEY_VALID_MASK) &&
+		(BIT(keyid) & tegra_se_keyslots));
+	mutex_unlock(&kslt_lock);
+
+	return ret;
+}
+
+static int tegra_key_insert(struct tegra_se *se, const u8 *key,
+			    u32 keylen, u16 slot, u32 alg)
+{
+	const u32 *keyval = (u32 *)key;
+	u32 *addr = se->cmdbuf->addr, size;
+
+	size = tegra_key_prep_ins_cmd(se, addr, keyval, keylen, slot, alg);
+
+	return tegra_se_host1x_submit(se, size);
+}
+
+void tegra_key_invalidate(struct tegra_se *se, u32 keyid, u32 alg)
+{
+	u8 zkey[AES_MAX_KEY_SIZE] = {0};
+
+	if (!keyid)
+		return;
+
+	/* Overwrite the key with 0s */
+	tegra_key_insert(se, zkey, AES_MAX_KEY_SIZE, keyid, alg);
+
+	tegra_keyslot_free(keyid);
+}
+
+int tegra_key_submit(struct tegra_se *se, const u8 *key, u32 keylen, u32 alg, u32 *keyid)
+{
+	int ret;
+
+	/* Use the existing slot if it is already allocated */
+	if (!tegra_key_in_kslt(*keyid)) {
+		*keyid = tegra_keyslot_alloc();
+		if (!(*keyid)) {
+			dev_err(se->dev, "failed to allocate key slot\n");
+			return -ENOMEM;
+		}
+	}
+
+	ret = tegra_key_insert(se, key, keylen, *keyid, alg);
+	if (ret)
+		return ret;
+
+	return 0;
+}