From: Anup Patel <anup.patel@broadcom.com>
To: Vinod Koul <vinod.koul@intel.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S . Miller" <davem@davemloft.net>,
Jassi Brar <jassisinghbrar@gmail.com>
Cc: devicetree@vger.kernel.org, Anup Patel <anup.patel@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
Jon Mason <jonmason@broadcom.com>, Ray Jui <rjui@broadcom.com>,
linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
bcm-kernel-feedback-list@broadcom.com,
linux-crypto@vger.kernel.org, Rob Rice <rob.rice@broadcom.com>,
dmaengine@vger.kernel.org,
Dan Williams <dan.j.williams@intel.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/4] lib/raid6: Add log-of-2 table for RAID6 HW requiring disk position
Date: Fri, 10 Feb 2017 14:37:05 +0530 [thread overview]
Message-ID: <1486717628-17580-2-git-send-email-anup.patel@broadcom.com> (raw)
In-Reply-To: <1486717628-17580-1-git-send-email-anup.patel@broadcom.com>
The raid6_gfexp table represents {2}^n values for 0 <= n < 256. The
Linux async_tx framework pass values from raid6_gfexp as coefficients
for each source to prep_dma_pq() callback of DMA channel with PQ
capability. This creates problem for RAID6 offload engines (such as
Broadcom SBA) which take disk position (i.e. log of {2}) instead of
multiplicative cofficients from raid6_gfexp table.
This patch adds raid6_gflog table having log-of-2 value for any given
x such that 0 <= x < 256. For any given disk coefficient x, the
corresponding disk position is given by raid6_gflog[x]. The RAID6
offload engine driver can use this newly added raid6_gflog table to
get disk position from multiplicative coefficient.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
---
include/linux/raid/pq.h | 1 +
lib/raid6/mktables.c | 20 ++++++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 4d57bba..30f9453 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -142,6 +142,7 @@ int raid6_select_algo(void);
extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
extern const u8 raid6_vgfmul[256][32] __attribute__((aligned(256)));
extern const u8 raid6_gfexp[256] __attribute__((aligned(256)));
+extern const u8 raid6_gflog[256] __attribute__((aligned(256)));
extern const u8 raid6_gfinv[256] __attribute__((aligned(256)));
extern const u8 raid6_gfexi[256] __attribute__((aligned(256)));
diff --git a/lib/raid6/mktables.c b/lib/raid6/mktables.c
index 39787db..e824d08 100644
--- a/lib/raid6/mktables.c
+++ b/lib/raid6/mktables.c
@@ -125,6 +125,26 @@ int main(int argc, char *argv[])
printf("EXPORT_SYMBOL(raid6_gfexp);\n");
printf("#endif\n");
+ /* Compute log-of-2 table */
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_gflog[256] =\n" "{\n");
+ for (i = 0; i < 256; i += 8) {
+ printf("\t");
+ for (j = 0; j < 8; j++) {
+ v = 255;
+ for (k = 0; k < 256; k++)
+ if (exptbl[k] == (i + j)) {
+ v = k;
+ break;
+ }
+ printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
+ }
+ }
+ printf("};\n");
+ printf("#ifdef __KERNEL__\n");
+ printf("EXPORT_SYMBOL(raid6_gflog);\n");
+ printf("#endif\n");
+
/* Compute inverse table x^-1 == x^254 */
printf("\nconst u8 __attribute__((aligned(256)))\n"
"raid6_gfinv[256] =\n" "{\n");
--
2.7.4
next prev parent reply other threads:[~2017-02-10 9:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-10 9:07 [PATCH v3 0/4] Broadcom SBA RAID support Anup Patel
2017-02-10 9:07 ` Anup Patel [this message]
2017-02-10 9:07 ` [PATCH v3 2/4] async_tx: Fix DMA_PREP_FENCE usage in do_async_gen_syndrome() Anup Patel
2017-02-10 9:07 ` [PATCH v3 3/4] dmaengine: Add Broadcom SBA RAID driver Anup Patel
2017-02-10 17:50 ` Dan Williams
2017-02-13 9:13 ` Anup Patel
2017-02-14 4:00 ` Anup Patel
[not found] ` <CAPcyv4hE5gDiHhfaiHDHbhA2xKa45UdzKcSxnQXK-W92sr3Z1g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-02-14 5:24 ` Anup Patel
2017-02-10 9:07 ` [PATCH v3 4/4] dt-bindings: Add DT bindings document for " Anup Patel
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