From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCH 2/5] mmc: dw-mmc: ensure that the card is not busy when changing clock. Date: Mon, 27 Aug 2012 10:51:31 +0900 Message-ID: <503AD2A3.4020109@samsung.com> References: <503614A5.5090906@samsung.com> <00ac01cd81ac$3eef2370$bccd6a50$%jun@samsung.com> <503708A2.9030500@samsung.com> <000b01cd83f4$acda02c0$068e0840$%jun@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout2.samsung.com ([203.254.224.25]:16327 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750783Ab2H0Bvd (ORCPT ); Sun, 26 Aug 2012 21:51:33 -0400 Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0M9E007S755HF6G0@mailout2.samsung.com> for linux-mmc@vger.kernel.org; Mon, 27 Aug 2012 10:51:32 +0900 (KST) Received: from [10.90.51.55] by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0M9E00CBG55VVJ10@mmp2.samsung.com> for linux-mmc@vger.kernel.org; Mon, 27 Aug 2012 10:51:32 +0900 (KST) In-reply-to: <000b01cd83f4$acda02c0$068e0840$%jun@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Seungwon Jeon Cc: 'Jaehoon Chung' , 'linux-mmc' , 'Chris Ball' , 'Kyungmin Park' , 'Will Newton' , 'James Hogan' On 08/27/2012 10:38 AM, Seungwon Jeon wrote: > On Friday, August 24, 2012, Jaehoon Chung wrote: >> Hi Seungwon, >> >> On 08/24/2012 12:55 PM, Seungwon Jeon wrote: >>> Hi Jaehoon, >>> >>> On Thursday, August 23, 2012, Jaehoon Chung wrote: >>>> To avoid glitches in the card clock output, >>>> need to check whether card is busy or not. >>> Could you describe the problem more? >> synopsys spec is mentioned. (7.1 Software/Hardware Restrictions) >> "Before disabling clock, ensure that card is not busy due to any previous data command." >> >>> In which situation did you meet this? >> At specific board, i found the problem that didn't inform ciu. >> (It didn't produce always.) >> At that time, i checked the status register whether card is busy or not. >> (Start bit of CMD register is cleared, but card is busy.) >> Current code didn't check the card status. Just check whether the start-bit cleared. >> host regard that command is completed, will send the next command. >> But next command didn't issue because Card is busy. >> This patch can prevent this situation. >> >> If you have any comment or opinion, please let me know. it's great help to me > If you know a point in time, we can reproduce it. Well, i didn't sure that you can reproduce this. On trats board, this problem is produced when kernel is booting. Best Regards, Jaehoon Chung > >> >> Best Regards, >> Jaehoon Chung >>> >>> Thanks, >>> Seungwon Jeon >>>> >>>> Signed-off-by: Jaehoon Chung >>>> Signed-off-by: Kyungmin Park >>>> --- >>>> drivers/mmc/host/dw_mmc.c | 30 ++++++++++++++++++++++++------ >>>> drivers/mmc/host/dw_mmc.h | 1 + >>>> 2 files changed, 25 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c >>>> index 36f98c0..8bef3c2 100644 >>>> --- a/drivers/mmc/host/dw_mmc.c >>>> +++ b/drivers/mmc/host/dw_mmc.c >>>> @@ -623,6 +623,27 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg) >>>> cmd, arg, cmd_status); >>>> } >>>> >>>> +static void dw_mci_inform_ciu(struct dw_mci_slot *slot) >>>> +{ >>>> + struct dw_mci *host = slot->host; >>>> + unsigned long timeout = jiffies + msecs_to_jiffies(500); >>>> + u32 ctrl, status; >>>> + >>>> + do { >>>> + status = mci_readl(host, STATUS); >>>> + if (!(status & SDMMC_DATA_BUSY)) >>>> + break; >>>> + ctrl = mci_readl(host, CTRL); >>>> + ctrl |= SDMMC_CTRL_RESET; >>>> + mci_writel(host, CTRL, ctrl); >>>> + } while (time_before(jiffies, timeout)); >>>> + >>>> + if (status & SDMMC_DATA_BUSY) >>>> + dev_err(&slot->mmc->class_dev,"Card is busy..!\n"); >>>> + >>>> + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); >>>> +} >>>> + >>>> static void dw_mci_setup_bus(struct dw_mci_slot *slot) >>>> { >>>> struct dw_mci *host = slot->host; >>>> @@ -650,15 +671,13 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot) >>>> mci_writel(host, CLKSRC, 0); >>>> >>>> /* inform CIU */ >>>> - mci_send_cmd(slot, >>>> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); >>>> + dw_mci_inform_ciu(slot); >>>> >>>> /* set clock to desired speed */ >>>> mci_writel(host, CLKDIV, div); >>>> >>>> /* inform CIU */ >>>> - mci_send_cmd(slot, >>>> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); >>>> + dw_mci_inform_ciu(slot); >>>> >>>> /* enable clock; only low power if no SDIO */ >>>> clk_en_a = SDMMC_CLKEN_ENABLE << slot->id; >>>> @@ -667,8 +686,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot) >>>> mci_writel(host, CLKENA, clk_en_a); >>>> >>>> /* inform CIU */ >>>> - mci_send_cmd(slot, >>>> - SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0); >>>> + dw_mci_inform_ciu(slot); >>>> >>>> host->current_speed = slot->clock; >>>> } >>>> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h >>>> index 15c27e1..b6a1a78 100644 >>>> --- a/drivers/mmc/host/dw_mmc.h >>>> +++ b/drivers/mmc/host/dw_mmc.h >>>> @@ -127,6 +127,7 @@ >>>> #define SDMMC_CMD_INDX(n) ((n) & 0x1F) >>>> /* Status register defines */ >>>> #define SDMMC_GET_FCNT(x) (((x)>>17) & 0x1FFF) >>>> +#define SDMMC_DATA_BUSY BIT(9) >>>> /* Internal DMAC interrupt defines */ >>>> #define SDMMC_IDMAC_INT_AI BIT(9) >>>> #define SDMMC_IDMAC_INT_NI BIT(8) >>>> -- >>>> 1.7.4.1 >>>> -- >>>> 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 >>> >> >> -- >> 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 >