From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Date: Mon, 12 Jan 2015 10:45:34 +0900 Subject: [U-Boot] [PATCH 1/3] samsung: board: support eMMC reset using DT In-Reply-To: References: <1420695867-1621-1-git-send-email-jy0922.shim@samsung.com> <54AF83BE.2050905@samsung.com> <54AFB7D6.3070307@samsung.com> <54B0CC5A.6030305@samsung.com> Message-ID: <54B3273E.1050609@samsung.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 01/11/2015 02:46 AM, Simon Glass wrote: > Hi, > > > On 9 January 2015 at 23:53, Joonyoung Shim wrote: >> On 01/09/2015 08:13 PM, Jaehoon Chung wrote: >>> On 01/09/2015 04:31 PM, Joonyoung Shim wrote: >>>> +Cc Jaehoon, >>>> >>>> On 01/09/2015 03:18 AM, Simon Glass wrote: >>>>> Hi Joonyoung, >>>>> >>>>> On 7 January 2015 at 22:44, Joonyoung Shim wrote: >>>>>> Some exynos boards require special handling of SD4_nRESET_OUT line for >>>>>> eMMC memory to perform complete reboot e.g. Odroid X2/U3/XU3 boards. >>>>>> >>>>>> This will support eMMC reset using DT from reset_misc of samsung common >>>>>> board file and each board files can support eMMC reset on non DT case. >>>>>> >>>>>> Signed-off-by: Joonyoung Shim >>>>>> --- >>>>>> board/samsung/common/board.c | 27 ++++++++++++++++++++++++++ >>>>>> board/samsung/odroid/odroid.c | 2 +- >>>>>> doc/device-tree-bindings/exynos/emmc-reset.txt | 15 ++++++++++++++ >>>>>> 3 files changed, 43 insertions(+), 1 deletion(-) >>>>>> create mode 100644 doc/device-tree-bindings/exynos/emmc-reset.txt >>>>>> >>>>>> diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c >>>>>> index c04ab3c..3218463 100644 >>>>>> --- a/board/samsung/common/board.c >>>>>> +++ b/board/samsung/common/board.c >>>>>> @@ -40,6 +40,8 @@ __weak int exynos_power_init(void) >>>>>> return 0; >>>>>> } >>>>>> >>>>>> +__weak void exynos_reset_misc(void) {} >>>>>> + >>>>>> #if defined CONFIG_EXYNOS_TMU >>>>>> /* Boot Time Thermal Analysis for SoC temperature threshold breach */ >>>>>> static void boot_temp_check(void) >>>>>> @@ -400,3 +402,28 @@ int misc_init_r(void) >>>>>> return 0; >>>>>> } >>>>>> #endif >>>>>> + >>>>>> +void reset_misc(void) >>>>>> +{ >>>>>> +#ifdef CONFIG_OF_CONTROL >>>>> >>>>> I think all Samsung boards have this defined, so this #ifdef can be removed. >>>>> >>>> >>>> OK, if it is true, we can remove this and i will not to support non DT case. >>>> >>>>>> + struct gpio_desc gpio = {}; >>>>>> + int node; >>>>>> + >>>>>> + node = fdt_node_offset_by_compatible(gd->fdt_blob, 0, >>>>>> + "samsung,emmc-reset"); >>>>>> + if (node < 0) >>>>>> + return; >>>>>> + >>>>>> + gpio_request_by_name_nodev(gd->fdt_blob, node, "reset-gpio", 0, &gpio, >>>>>> + GPIOD_IS_OUT); >>>>>> + >>>>>> + if (dm_gpio_is_valid(&gpio)) { >>>>>> + /* Reset eMMC*/ >>>>>> + dm_gpio_set_value(&gpio, 0); >>>>>> + mdelay(10); >>>>> >>>>> That's a very long reset! Is that what it needs? >>>>> >>>> >>>> Jaehoon, is there any guide about wait time of reset at eMMC spec? >>> >>> Well, I'm not sure, but as Simon's comments, it's long time. >>> (Minimum is 1us...Maximum isn't defined.) >>> >> >> This just comes from reset_misc() of board/samsung/odroid/odroid.c file. >> Even, hardkernel u-boot waits 50msec. > > The only info I have immediately to hand is the 'JEDEC Standard No. > 84-A441' (eMMC) and it says a 1uS pulse is required. So can we change > this to udelay(1)? It's minimum value, that's not problem that 10msec is set. But if change this value, i think good that it changes to greater value than 1us. Best Regards, Jaehoon Chung > > Regards, > Simon >