From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCH] Revert "mmc: dw_mmc: Add check for IDMAC configuration" Date: Tue, 11 Sep 2012 13:46:05 +0900 Message-ID: <504EC20D.2030105@samsung.com> References: <00d801cd8fc4$738f8540$5aae8fc0$%jun@samsung.com> <504EBFCA.3080203@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout1.samsung.com ([203.254.224.24]:55669 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751566Ab2IKEqK (ORCPT ); Tue, 11 Sep 2012 00:46:10 -0400 Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MA600EQI58SK1I0@mailout1.samsung.com> for linux-mmc@vger.kernel.org; Tue, 11 Sep 2012 13:46:08 +0900 (KST) Received: from [10.90.51.55] by mmp1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MA600IDP58WPE90@mmp1.samsung.com> for linux-mmc@vger.kernel.org; Tue, 11 Sep 2012 13:46:08 +0900 (KST) In-reply-to: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Girish K S Cc: Jaehoon Chung , Seungwon Jeon , linux-mmc@vger.kernel.org, cjb@laptop.org, will.newton@imgtec.com, James Hogan On 09/11/2012 01:40 PM, Girish K S wrote: > On 11 September 2012 10:06, Jaehoon Chung wrote: >> On 09/11/2012 12:46 PM, Girish K S wrote: >>> On 11 September 2012 07:53, Seungwon Jeon wrote: >>>> This reverts commit 94c6cee91(Add check for IDMAC configuration). >>>> Synopsys says that only if internal dmac is not present, optional >>>> external dma interface is present. When internal dmac is present, >>>> '0' value in DMA_INTERFACE of HCON is reasonable. DMA_INTERFACE >>>> indicates external dma interface. And idmac initialization is >>>> prohibited now. So, let's revert this commit. >>> >>> There is no register, or a field in any register which says IDMAC present. >>> I can see only use_idmac bit field in CTRL register. >>> So in first place how will i know whether IDMAC is present? Have you >>> assumed that IDMAC is present. >>> I would like to know without assuming, whether IDMAC is present. >>> If i have missed out something let me know. i will check and revert back >> I understood that if INTERNAL_DMAC at HCON register is set to 1, we didn't consdier the DMA_INTERFACE's value. > I cannot see any field by name INTERNAL_DMAC in the HCON: can you > please tell me the bit position of it. > I think INTERNAL_DMAC is the signal interface to AXI master. Sorry, You're right. there is no field for INTERNAL_DMAC at HCON register. >> So although dma_interface is set to 0 or others, host can use the internal DMA. >> >> Best Regards, >> Jaehoon Chung >>> >>>> >>>> CC: Girish K S >>>> Signed-off-by: Seungwon Jeon >>>> --- >>>> drivers/mmc/host/dw_mmc.c | 15 ++------------- >>>> 1 files changed, 2 insertions(+), 13 deletions(-) >>>> >>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c >>>> index 36f98c0..dcbe9aa 100644 >>>> --- a/drivers/mmc/host/dw_mmc.c >>>> +++ b/drivers/mmc/host/dw_mmc.c >>>> @@ -405,23 +405,11 @@ static void dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len) >>>> static int dw_mci_idmac_init(struct dw_mci *host) >>>> { >>>> struct idmac_desc *p; >>>> - int i, dma_support; >>>> + int i; >>>> >>>> /* Number of descriptors in the ring buffer */ >>>> host->ring_size = PAGE_SIZE / sizeof(struct idmac_desc); >>>> >>>> - /* Check if Hardware Configuration Register has support for DMA */ >>>> - dma_support = (mci_readl(host, HCON) >> 16) & 0x3; >>>> - >>>> - if (!dma_support || dma_support > 2) { >>>> - dev_err(&host->dev, >>>> - "Host Controller does not support IDMA Tx.\n"); >>>> - host->dma_ops = NULL; >>>> - return -ENODEV; >>>> - } >>>> - >>>> - dev_info(&host->dev, "Using internal DMA controller.\n"); >>>> - >>>> /* Forward link the descriptor list */ >>>> for (i = 0, p = host->sg_cpu; i < host->ring_size - 1; i++, p++) >>>> p->des3 = host->sg_dma + (sizeof(struct idmac_desc) * (i + 1)); >>>> @@ -1895,6 +1883,7 @@ static void dw_mci_init_dma(struct dw_mci *host) >>>> /* Determine which DMA interface to use */ >>>> #ifdef CONFIG_MMC_DW_IDMAC >>>> host->dma_ops = &dw_mci_idmac_ops; >>>> + dev_info(&host->dev, "Using internal DMA controller.\n"); >>>> #endif >>>> >>>> if (!host->dma_ops) >>>> -- >>>> 1.7.0.4 >>>> >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >