crypto: atmel-aes - add debug facilities to monitor register accesses.

This feature should not be enabled in release but can be usefull for
developers who need to monitor register accesses at some specific places.
Set the AES_FLAGS_DUMP_REG flag inside dd->flags to start monitoring the
I/O accesses, clear it to stop monitoring.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/atmel-aes.c

@@ -75,6 +75,7 @@
 
 #define AES_FLAGS_INIT		BIT(2)
 #define AES_FLAGS_BUSY		BIT(3)
+#define AES_FLAGS_DUMP_REG	BIT(4)
 
 #define AES_FLAGS_PERSISTENT	(AES_FLAGS_INIT | AES_FLAGS_BUSY)
 
@@ -197,16 +198,128 @@ static struct atmel_aes_drv atmel_aes = {
 	.lock = __SPIN_LOCK_UNLOCKED(atmel_aes.lock),
 };
 
+#ifdef VERBOSE_DEBUG
+static const char *atmel_aes_reg_name(u32 offset, char *tmp, size_t sz)
+{
+	switch (offset) {
+	case AES_CR:
+		return "CR";
+
+	case AES_MR:
+		return "MR";
+
+	case AES_ISR:
+		return "ISR";
+
+	case AES_IMR:
+		return "IMR";
+
+	case AES_IER:
+		return "IER";
+
+	case AES_IDR:
+		return "IDR";
+
+	case AES_KEYWR(0):
+	case AES_KEYWR(1):
+	case AES_KEYWR(2):
+	case AES_KEYWR(3):
+	case AES_KEYWR(4):
+	case AES_KEYWR(5):
+	case AES_KEYWR(6):
+	case AES_KEYWR(7):
+		snprintf(tmp, sz, "KEYWR[%u]", (offset - AES_KEYWR(0)) >> 2);
+		break;
+
+	case AES_IDATAR(0):
+	case AES_IDATAR(1):
+	case AES_IDATAR(2):
+	case AES_IDATAR(3):
+		snprintf(tmp, sz, "IDATAR[%u]", (offset - AES_IDATAR(0)) >> 2);
+		break;
+
+	case AES_ODATAR(0):
+	case AES_ODATAR(1):
+	case AES_ODATAR(2):
+	case AES_ODATAR(3):
+		snprintf(tmp, sz, "ODATAR[%u]", (offset - AES_ODATAR(0)) >> 2);
+		break;
+
+	case AES_IVR(0):
+	case AES_IVR(1):
+	case AES_IVR(2):
+	case AES_IVR(3):
+		snprintf(tmp, sz, "IVR[%u]", (offset - AES_IVR(0)) >> 2);
+		break;
+
+	case AES_AADLENR:
+		return "AADLENR";
+
+	case AES_CLENR:
+		return "CLENR";
+
+	case AES_GHASHR(0):
+	case AES_GHASHR(1):
+	case AES_GHASHR(2):
+	case AES_GHASHR(3):
+		snprintf(tmp, sz, "GHASHR[%u]", (offset - AES_GHASHR(0)) >> 2);
+		break;
+
+	case AES_TAGR(0):
+	case AES_TAGR(1):
+	case AES_TAGR(2):
+	case AES_TAGR(3):
+		snprintf(tmp, sz, "TAGR[%u]", (offset - AES_TAGR(0)) >> 2);
+		break;
+
+	case AES_CTRR:
+		return "CTRR";
+
+	case AES_GCMHR(0):
+	case AES_GCMHR(1):
+	case AES_GCMHR(2):
+	case AES_GCMHR(3):
+		snprintf(tmp, sz, "GCMHR[%u]", (offset - AES_GCMHR(0)) >> 2);
+
+	default:
+		snprintf(tmp, sz, "0x%02x", offset);
+		break;
+	}
+
+	return tmp;
+}
+#endif /* VERBOSE_DEBUG */
+
 /* Shared functions */
 
 static inline u32 atmel_aes_read(struct atmel_aes_dev *dd, u32 offset)
 {
-	return readl_relaxed(dd->io_base + offset);
+	u32 value = readl_relaxed(dd->io_base + offset);
+
+#ifdef VERBOSE_DEBUG
+	if (dd->flags & AES_FLAGS_DUMP_REG) {
+		char tmp[16];
+
+		dev_vdbg(dd->dev, "read 0x%08x from %s\n", value,
+			 atmel_aes_reg_name(offset, tmp, sizeof(tmp)));
+	}
+#endif /* VERBOSE_DEBUG */
+
+	return value;
 }
 
 static inline void atmel_aes_write(struct atmel_aes_dev *dd,
 					u32 offset, u32 value)
 {
+#ifdef VERBOSE_DEBUG
+	if (dd->flags & AES_FLAGS_DUMP_REG) {
+		char tmp[16];
+
+		dev_vdbg(dd->dev, "write 0x%08x into %s\n", value,
+			 atmel_aes_reg_name(offset, tmp));
+	}
+#endif /* VERBOSE_DEBUG */
+
 	writel_relaxed(value, dd->io_base + offset);
 }