Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753580AbbDQJLP (ORCPT ); Fri, 17 Apr 2015 05:11:15 -0400 Received: from exprod5og104.obsmtp.com ([64.18.0.178]:41487 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752990AbbDQJLE (ORCPT ); Fri, 17 Apr 2015 05:11:04 -0400 MIME-Version: 1.0 In-Reply-To: <2380806.YAnOxsf686@wuerfel> References: <1429212673-22254-1-git-send-email-rsahu@apm.com> <2380806.YAnOxsf686@wuerfel> Date: Fri, 17 Apr 2015 14:41:02 +0530 Message-ID: Subject: Re: [PATCH v3] dmaengine: xgene-dma: Fix sparse wannings and coccinelle warnings From: Rameshwar Sahu To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Vinod Koul , dan.j.williams@intel.com, devicetree@vger.kernel.org, jcm@redhat.com, patches@apm.com, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3029 Lines: 85 Hi Arnd, On Fri, Apr 17, 2015 at 2:19 PM, Arnd Bergmann wrote: > On Friday 17 April 2015 01:01:13 Rameshwar Prasad Sahu wrote: >> v3 changes: >> * Minor changes in length setting in DMA descriptor >> >> v2 changes: >> * Code cleanup >> * Changed way of setting DMA descriptors for big-endian >> >> This patch fixes compilation sparse warnings like incorrect type in assignment >> (different base types), cast to restricted __le64, symbol >> '__UNIQUE_ID_author__COUNTER__' has multiple initializers etc and >> coccinelle warnings (No need to set .owner here. The core will do it.) >> >> This patch is based on slave-dma / for-linus branch. >> (commit: 9f2fd0dfa594d857fbdaeda523ff7a46f16567f5 [26/28] >> dmaengine: Add support for APM X-Gene SoC DMA engine driver) >> >> Reported-by: kbuild test robot >> Signed-off-by: Rameshwar Prasad Sahu > > Looks good now, > > Reviewed-by: Arnd Bergmann > > There is one small enhancement that you could still do and I'll shut up after > that ;-) > >> >> -static void *xgene_dma_lookup_ext8(u64 *desc, int idx) >> +static __le64 *xgene_dma_lookup_ext8(struct xgene_dma_desc_hw *desc, int idx) >> { >> - return (idx % 2) ? (desc + idx - 1) : (desc + idx + 1); >> + switch (idx) { >> + case 0: >> + return &desc->m1; >> + case 1: >> + return &desc->m0; >> + case 2: >> + return &desc->m3; >> + case 3: >> + return &desc->m2; >> + default: >> + pr_err("Invalid dma descriptor index\n"); >> + } >> + >> + return NULL; >> } >> > ... > >> /* Set 1st to 5th source addresses */ >> for (i = 0; i < src_cnt; i++) { >> len = *nbytes; >> - xgene_dma_set_src_buffer((i == 0) ? (desc1 + 8) : >> + xgene_dma_set_src_buffer((i == 0) ? &desc1->m1 : >> xgene_dma_lookup_ext8(desc2, i - 1), >> &len, &src[i]); >> - XGENE_DMA_DESC_MULTI_SET(desc1, scf[i], i); >> + desc1->m2 |= cpu_to_le64((scf[i] << ((i + 1) * 8))); >> } > > If you just unroll this loop, you get code that is smaller and easier to > understand: > > /* Set 1st to 5th source addresses */ > xgene_dma_set_src_buffer(&desc1->m1, &len, &src[0]); > xgene_dma_set_src_buffer(&desc2->m0, &len, &src[1]); > xgene_dma_set_src_buffer(&desc2->m3, &len, &src[2]); > xgene_dma_set_src_buffer(&desc2->m2, &len, &src[3]); > desc1->m2 |= cpu_to_le64(scf[0] | scf[1] << 8 | scf[2] << 16 | scf[3] << 24); Actually here, in run time src_cnt value can be 2 or 3 upto 5, so we can't unroll it. > > Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/