eMMC support in u-boot

heing · Jan 10th 2017

Do you plan to include support for the eMMC on armStoneA9r2 in u-boot?

There is a post containing some information on how to do this with the efusA9 board:
details of u-boot reading support for efusA9 emmc

I need to use eMMC for temporary storage when upgrading the root file system using the u-boot update command. I use the SD card for this today, but I would like to get rid of that dependency.

Kind regards,
Hein Gustavsen
Miros AS

fs-support_PH · Jan 12th 2017

At the moment this is not on top of our TODO list.
For EMMC support in UBoot there are a few tasks to do.
Here are some additional information why it's not done in a short time:
eMMC not accessible

I assume that your NAND is not big enough for some kind of recovery partition?

Best Regards
Your F&S Support Team

heing · Jan 12th 2017

Thank you for your reply. In my case, reading the eMMC would be sufficient since the writing is only done from Linux.

With R2, the NAND is actually big enough for a recovery partition. I will investigate that.

Kind regards,
Hein Gustavsen
Miros AS

heing · Jan 16th 2017

I created this patch based on linux device tree values and this forum post:
details of u-boot reading support for efusA9 emmc

Diff

diff -Naur a/board/F+S/fsimx6/fsimx6.c b/board/F+S/fsimx6/fsimx6.c
--- a/board/F+S/fsimx6/fsimx6.c 2016-08-08 19:07:02.000000000 +0200
+++ b/board/F+S/fsimx6/fsimx6.c 2017-01-16 10:54:48.165815770 +0100
@@ -475,6 +475,21 @@
IOMUX_PADS(PAD_NANDF_CS2__GPIO6_IO15 | MUX_PAD_CTRL(NO_PAD_CTRL)),/* CD */
};
+/* eMMC pads definition */
+static iomux_v3_cfg_t const usdhc3_emmc_pads[] = {
+ IOMUX_PADS(PAD_SD3_CLK__SD3_CLK | MUX_PAD_CTRL(0x17071)),
+ IOMUX_PADS(PAD_SD3_CMD__SD3_CMD | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT0__SD3_DATA0 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT1__SD3_DATA1 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT2__SD3_DATA2 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT3__SD3_DATA3 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT4__SD3_DATA4 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT5__SD3_DATA5 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT6__SD3_DATA6 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_DAT7__SD3_DATA7 | MUX_PAD_CTRL(0x10071)),
+ IOMUX_PADS(PAD_SD3_RST__SD3_RESET | MUX_PAD_CTRL(0x1B071)),/* Reset eMMC, active low */
+};
+
struct fsl_esdhc_cfg esdhc_cfg[] = {
{
.esdhc_base = USDHC1_BASE_ADDR,
@@ -505,7 +520,12 @@
return !gpio_get_value(IMX_GPIO_NR(6, 15));
case BT_ARMSTONEA9R2:
- return !gpio_get_value(IMX_GPIO_NR(1, 4));
+ if (mmc->block_dev.dev == 0)
+ /* External SD card slot has Card Detect (CD) */
+ return !gpio_get_value(IMX_GPIO_NR(1, 4));
+ else
+ /* On-board SD card slot has no Card Detect (CD) */
+ return 1; /* Assume card is present */
case BT_PICOMODA9:
if (mmc->block_dev.dev == 0)
@@ -612,6 +632,12 @@
index = 0;
break;
+ case BT_ARMSTONEA9R2:
+ SETUP_IOMUX_PADS(usdhc3_emmc_pads);
+ ccgr6 |= (3 << 6);
+ index = 2;
+ break;
+
default:
return 0; /* No more SD card slots */
}

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I can now read the eMMC, but I don't know the meaning of the ccgr6 value. Could you please explain?

Kind regards,
Hein Gustavsen
Miros AS

fs-support_HK · Jan 26th 2017

This is the clock for the USDHC device. You have to enable the clock to the device or you can not use the device.

We are currently also revising the SD initialization, so maybe I have a solution, too, very soon.

Your F&S Support Team

heing · Jan 26th 2017

Thank you!

eMMC support in u-boot

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