hwrng: cn10k - Add extended trng register support

The way random data is read from hardware has changed from
Octeon CN10KA-B0 and later SoCs onwards. A new set of registers
have been added to read random data and to verify whether the
read data is valid or not. This patch extends and uses
RNM_PF_TRNG_DAT and RNM_PF_TRNG_STS CSRs to read random number
and status for the applicable silicon variants.

Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/cn10k-rng.c b/drivers/char/hw_random/cn10k-rng.c
index c1193f8..0cd7e1a 100644 (file)
--- a/drivers/char/hw_random/cn10k-rng.c
+++ b/drivers/char/hw_random/cn10k-rng.c
@@ -23,14 +23,49 @@
 #define RNM_PF_RANDOM          0x400
 #define RNM_TRNG_RESULT                0x408
 
+/* Extended TRNG Read and Status Registers */
+#define RNM_PF_TRNG_DAT                0x1000
+#define RNM_PF_TRNG_RES                0x1008
+
 struct cn10k_rng {
        void __iomem *reg_base;
        struct hwrng ops;
        struct pci_dev *pdev;
+       /* Octeon CN10K-A A0/A1, CNF10K-A A0/A1 and CNF10K-B A0/B0
+        * does not support extended TRNG registers
+        */
+       bool extended_trng_regs;
 };
 
 #define PLAT_OCTEONTX_RESET_RNG_EBG_HEALTH_STATE     0xc2000b0f
 
+#define PCI_SUBSYS_DEVID_CN10K_A_RNG   0xB900
+#define PCI_SUBSYS_DEVID_CNF10K_A_RNG  0xBA00
+#define PCI_SUBSYS_DEVID_CNF10K_B_RNG  0xBC00
+
+static bool cn10k_is_extended_trng_regs_supported(struct pci_dev *pdev)
+{
+       /* CN10K-A A0/A1 */
+       if ((pdev->subsystem_device == PCI_SUBSYS_DEVID_CN10K_A_RNG) &&
+           (!pdev->revision || (pdev->revision & 0xff) == 0x50 ||
+            (pdev->revision & 0xff) == 0x51))
+               return false;
+
+       /* CNF10K-A A0 */
+       if ((pdev->subsystem_device == PCI_SUBSYS_DEVID_CNF10K_A_RNG) &&
+           (!pdev->revision || (pdev->revision & 0xff) == 0x60 ||
+            (pdev->revision & 0xff) == 0x61))
+               return false;
+
+       /* CNF10K-B A0/B0 */
+       if ((pdev->subsystem_device == PCI_SUBSYS_DEVID_CNF10K_B_RNG) &&
+           (!pdev->revision || (pdev->revision & 0xff) == 0x70 ||
+            (pdev->revision & 0xff) == 0x74))
+               return false;
+
+       return true;
+}
+
 static unsigned long reset_rng_health_state(struct cn10k_rng *rng)
 {
        struct arm_smccc_res res;
@@ -63,9 +98,23 @@ static int check_rng_health(struct cn10k_rng *rng)
        return 0;
 }
 
-static void cn10k_read_trng(struct cn10k_rng *rng, u64 *value)
+/* Returns true when valid data available otherwise return false */
+static bool cn10k_read_trng(struct cn10k_rng *rng, u64 *value)
 {
+       u16 retry_count = 0;
        u64 upper, lower;
+       u64 status;
+
+       if (rng->extended_trng_regs) {
+               do {
+                       *value = readq(rng->reg_base + RNM_PF_TRNG_DAT);
+                       if (*value)
+                               return true;
+                       status = readq(rng->reg_base + RNM_PF_TRNG_RES);
+                       if (!status && (retry_count++ > 0x1000))
+                               return false;
+               } while (!status);
+       }
 
        *value = readq(rng->reg_base + RNM_PF_RANDOM);
 
@@ -82,6 +131,7 @@ static void cn10k_read_trng(struct cn10k_rng *rng, u64 *value)
 
                *value = (upper & 0xFFFFFFFF00000000) | (lower & 0xFFFFFFFF);
        }
+       return true;
 }
 
 static int cn10k_rng_read(struct hwrng *hwrng, void *data,
@@ -100,7 +150,8 @@ static int cn10k_rng_read(struct hwrng *hwrng, void *data,
        size = max;
 
        while (size >= 8) {
-               cn10k_read_trng(rng, &value);
+               if (!cn10k_read_trng(rng, &value))
+                       goto out;
 
                *((u64 *)pos) = value;
                size -= 8;
@@ -108,7 +159,8 @@ static int cn10k_rng_read(struct hwrng *hwrng, void *data,
        }
 
        if (size > 0) {
-               cn10k_read_trng(rng, &value);
+               if (!cn10k_read_trng(rng, &value))
+                       goto out;
 
                while (size > 0) {
                        *pos = (u8)value;
@@ -118,6 +170,7 @@ static int cn10k_rng_read(struct hwrng *hwrng, void *data,
                }
        }
 
+out:
        return max - size;
 }
 
@@ -144,9 +197,11 @@ static int cn10k_rng_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (!rng->ops.name)
                return -ENOMEM;
 
-       rng->ops.read    = cn10k_rng_read;
+       rng->ops.read = cn10k_rng_read;
        rng->ops.priv = (unsigned long)rng;
 
+       rng->extended_trng_regs = cn10k_is_extended_trng_regs_supported(pdev);
+
        reset_rng_health_state(rng);
 
        err = devm_hwrng_register(&pdev->dev, &rng->ops);