2013-03-12 08:28:56

by Vakul Garg

Subject: [PATCHv1] crypto: caam - set RDB bit in security configuration register

This change is required for post SEC-5.0 devices which have RNG4.
Setting RDB in security configuration register allows CAAM to use the
"Random Data Buffer" to be filled by a single request. The Random Data
Buffer is large enough for ten packets to get their IVs from a single
request. If the Random Data Buffer is not enabled, then each IV causes a
separate request, and RNG4 hardware cannot keep up resulting in lower
IPSEC throughput if random IVs are used.

Signed-off-by: Vakul Garg <[email protected]>
---
Sorry for repeated sending.
Resending as suggested by Herbert.

Changes in v1: Addressed Kim Philip's comments.
(a) Limit commit message to 75 characters.
(b) Relocated code to set RDB bit in RNG4 initialisation section

drivers/crypto/caam/ctrl.c | 3 +++
drivers/crypto/caam/regs.h | 4 +++-
2 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index bf20dd8..79278d5 100644
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -304,6 +304,9 @@ static int caam_probe(struct platform_device *pdev)
caam_remove(pdev);
return ret;
}
+
+ /* Enable RDB bit so that RNG works faster */
+ setbits32(&topregs->ctrl.scfgr, SCFGR_RDBENABLE);
}

/* NOTE: RTIC detection ought to go here, around Si time */
diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h
index 3223fc6..cd6feda 100644
--- a/drivers/crypto/caam/regs.h
+++ b/drivers/crypto/caam/regs.h
@@ -252,7 +252,8 @@ struct caam_ctrl {
/* Read/Writable */
u32 rsvd1;
u32 mcr; /* MCFG Master Config Register */
- u32 rsvd2[2];
+ u32 rsvd2;
+ u32 scfgr; /* SCFGR, Security Config Register */

/* Bus Access Configuration Section 010-11f */
/* Read/Writable */
@@ -299,6 +300,7 @@ struct caam_ctrl {
#define MCFGR_WDFAIL 0x20000000 /* DECO watchdog force-fail */
#define MCFGR_DMA_RESET 0x10000000
#define MCFGR_LONG_PTR 0x00010000 /* Use >32-bit desc addressing */
+#define SCFGR_RDBENABLE 0x00000400

/* AXI read cache control */
#define MCFGR_ARCACHE_SHIFT 12
--
1.7.7.6

2013-03-21 09:54:49

by Herbert Xu

Subject: Re: [PATCHv1] crypto: caam - set RDB bit in security configuration register

On Tue, Mar 12, 2013 at 01:55:21PM +0530, Vakul Garg wrote:
> This change is required for post SEC-5.0 devices which have RNG4.
> Setting RDB in security configuration register allows CAAM to use the
> "Random Data Buffer" to be filled by a single request. The Random Data
> Buffer is large enough for ten packets to get their IVs from a single
> request. If the Random Data Buffer is not enabled, then each IV causes a
> separate request, and RNG4 hardware cannot keep up resulting in lower
> IPSEC throughput if random IVs are used.
>
> Signed-off-by: Vakul Garg <[email protected]>

Patch applied. Thanks!
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt