crypto: caam - enable prediction resistance in HRWNG

Instantiate CAAM RNG with prediction resistance enabled to improve its
quality (with PR on DRNG is forced to reseed from TRNG every time
random data is generated).

Management Complex firmware with version lower than 10.20.0
doesn't provide prediction resistance support. Consider this
and only instantiate rng when mc f/w version is lower.

Signed-off-by: Andrey Smirnov <[e-mail]>
Signed-off-by: Andrei Botila <[e-mail]>
Cc: Chris Healy <[e-mail]>
Cc: Lucas Stach <[e-mail]>
Cc: Horia Geantă <[e-mail]>
Cc: Herbert Xu <[e-mail]>
Cc: Iuliana Prodan <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Reviewed-by: Horia Geantă <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/caam/Kconfig

···
 	depends on FSL_SOC || ARCH_MXC || ARCH_LAYERSCAPE
 	select SOC_BUS
 	select CRYPTO_DEV_FSL_CAAM_COMMON
+	imply FSL_MC_BUS
 	help
 	  Enables the driver module for Freescale's Cryptographic Accelerator
 	  and Assurance Module (CAAM), also known as the SEC version 4 (SEC4).

drivers/crypto/caam/caamrng.c

···
 {
 	init_job_desc(desc, 0);	/* + 1 cmd_sz */
 	/* Generate random bytes: + 1 cmd_sz */
-	append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG);
+	append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG |
+			 OP_ALG_PR_ON);
 	/* Store bytes: + 1 cmd_sz + caam_ptr_sz  */
 	append_fifo_store(desc, dst_dma, len, FIFOST_TYPE_RNGSTORE);
 

drivers/crypto/caam/ctrl.c

···
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/sys_soc.h>
+#include <linux/fsl/mc.h>
 
 #include "compat.h"
 #include "regs.h"
···
 	init_job_desc(desc, 0);
 
 	op_flags = OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG |
-			(handle << OP_ALG_AAI_SHIFT) | OP_ALG_AS_INIT;
+			(handle << OP_ALG_AAI_SHIFT) | OP_ALG_AS_INIT |
+			OP_ALG_PR_ON;
 
 	/* INIT RNG in non-test mode */
 	append_operation(desc, op_flags);
···
 		return -ENOMEM;
 
 	for (sh_idx = 0; sh_idx < RNG4_MAX_HANDLES; sh_idx++) {
+		const u32 rdsta_if = RDSTA_IF0 << sh_idx;
+		const u32 rdsta_pr = RDSTA_PR0 << sh_idx;
+		const u32 rdsta_mask = rdsta_if | rdsta_pr;
 		/*
 		 * If the corresponding bit is set, this state handle
 		 * was initialized by somebody else, so it's left alone.
 		 */
-		if ((1 << sh_idx) & state_handle_mask)
-			continue;
+		if (rdsta_if & state_handle_mask) {
+			if (rdsta_pr & state_handle_mask)
+				continue;
+
+			dev_info(ctrldev,
+				 "RNG4 SH%d was previously instantiated without prediction resistance. Tearing it down\n",
+				 sh_idx);
+
+			ret = deinstantiate_rng(ctrldev, rdsta_if);
+			if (ret)
+				break;
+		}
 
 		/* Create the descriptor for instantiating RNG State Handle */
 		build_instantiation_desc(desc, sh_idx, gen_sk);
···
 		if (ret)
 			break;
 
-		rdsta_val = rd_reg32(&ctrl->r4tst[0].rdsta) & RDSTA_IFMASK;
+		rdsta_val = rd_reg32(&ctrl->r4tst[0].rdsta) & RDSTA_MASK;
 		if ((status && status != JRSTA_SSRC_JUMP_HALT_CC) ||
-		    !(rdsta_val & (1 << sh_idx))) {
+		    (rdsta_val & rdsta_mask) != rdsta_mask) {
 			ret = -EAGAIN;
 			break;
 		}
···
 }
 #endif
 
+#ifdef CONFIG_FSL_MC_BUS
+static bool check_version(struct fsl_mc_version *mc_version, u32 major,
+			  u32 minor, u32 revision)
+{
+	if (mc_version->major > major)
+		return true;
+
+	if (mc_version->major == major) {
+		if (mc_version->minor > minor)
+			return true;
+
+		if (mc_version->minor == minor &&
+		    mc_version->revision > revision)
+			return true;
+	}
+
+	return false;
+}
+#endif
+
 /* Probe routine for CAAM top (controller) level */
 static int caam_probe(struct platform_device *pdev)
 {
···
 	u8 rng_vid;
 	int pg_size;
 	int BLOCK_OFFSET = 0;
+	bool pr_support = false;
 
 	ctrlpriv = devm_kzalloc(&pdev->dev, sizeof(*ctrlpriv), GFP_KERNEL);
 	if (!ctrlpriv)
···
 
 	/* Get the IRQ of the controller (for security violations only) */
 	ctrlpriv->secvio_irq = irq_of_parse_and_map(nprop, 0);
+	np = of_find_compatible_node(NULL, NULL, "fsl,qoriq-mc");
+	ctrlpriv->mc_en = !!np;
+	of_node_put(np);
+
+#ifdef CONFIG_FSL_MC_BUS
+	if (ctrlpriv->mc_en) {
+		struct fsl_mc_version *mc_version;
+
+		mc_version = fsl_mc_get_version();
+		if (mc_version)
+			pr_support = check_version(mc_version, 10, 20, 0);
+		else
+			return -EPROBE_DEFER;
+	}
+#endif
 
 	/*
 	 * Enable DECO watchdogs and, if this is a PHYS_ADDR_T_64BIT kernel,
···
 	 * In case of SoCs with Management Complex, MC f/w performs
 	 * the configuration.
 	 */
-	np = of_find_compatible_node(NULL, NULL, "fsl,qoriq-mc");
-	ctrlpriv->mc_en = !!np;
-	of_node_put(np);
-
 	if (!ctrlpriv->mc_en)
 		clrsetbits_32(&ctrl->mcr, MCFGR_AWCACHE_MASK,
 			      MCFGR_AWCACHE_CACH | MCFGR_AWCACHE_BUFF |
···
 	 * already instantiated, do RNG instantiation
 	 * In case of SoCs with Management Complex, RNG is managed by MC f/w.
 	 */
-	if (!ctrlpriv->mc_en && rng_vid >= 4) {
+	if (!(ctrlpriv->mc_en && pr_support) && rng_vid >= 4) {
 		ctrlpriv->rng4_sh_init =
 			rd_reg32(&ctrl->r4tst[0].rdsta);
 		/*
···
 		 * to regenerate these keys before the next POR.
 		 */
 		gen_sk = ctrlpriv->rng4_sh_init & RDSTA_SKVN ? 0 : 1;
-		ctrlpriv->rng4_sh_init &= RDSTA_IFMASK;
+		ctrlpriv->rng4_sh_init &= RDSTA_MASK;
 		do {
 			int inst_handles =
 				rd_reg32(&ctrl->r4tst[0].rdsta) &
-								RDSTA_IFMASK;
+								RDSTA_MASK;
 			/*
 			 * If either SH were instantiated by somebody else
 			 * (e.g. u-boot) then it is assumed that the entropy
···
 		 * Set handles init'ed by this module as the complement of the
 		 * already initialized ones
 		 */
-		ctrlpriv->rng4_sh_init = ~ctrlpriv->rng4_sh_init & RDSTA_IFMASK;
+		ctrlpriv->rng4_sh_init = ~ctrlpriv->rng4_sh_init & RDSTA_MASK;
 
 		/* Enable RDB bit so that RNG works faster */
 		clrsetbits_32(&ctrl->scfgr, 0, SCFGR_RDBENABLE);

drivers/crypto/caam/desc.h

···
 #define OP_ALG_ICV_OFF		(0 << OP_ALG_ICV_SHIFT)
 #define OP_ALG_ICV_ON		(1 << OP_ALG_ICV_SHIFT)
 
+#define OP_ALG_PR_ON		BIT(1)
+
 #define OP_ALG_DIR_SHIFT	0
 #define OP_ALG_DIR_MASK		1
 #define OP_ALG_DECRYPT		0

drivers/crypto/caam/regs.h

···
 	u32 rsvd1[40];
 #define RDSTA_SKVT 0x80000000
 #define RDSTA_SKVN 0x40000000
+#define RDSTA_PR0 BIT(4)
+#define RDSTA_PR1 BIT(5)
 #define RDSTA_IF0 0x00000001
 #define RDSTA_IF1 0x00000002
-#define RDSTA_IFMASK (RDSTA_IF1 | RDSTA_IF0)
+#define RDSTA_MASK (RDSTA_PR1 | RDSTA_PR0 | RDSTA_IF1 | RDSTA_IF0)
 	u32 rdsta;
 	u32 rsvd2[15];
 };