Dear @jrhaws ,
OK, good job!
your test is very important for solving the issue. in order to improve performance of your wifi, let me explain technical details for you. Then you can continue to test it.
1. Explanation for why adding no-1-8-v property to usdhc1 node
On our i.MX6ULL-EVK, by default, SD1 IO level is 3.3V, so the SD interface can only support less than or equal to 50MHz frequency, which also means that the SD interface can only work on SD2.0 spec. So I suggested you add no-1-8-v to uSDHC1 node.
BUT after adding the property, you wifi module's max speed is 50MHz, only support 2 modes: Low speed 25MHz, high speed 50MHz(SDR50 mode)
2. How to improve WiFi performance
(1) Using 1.8V IO level
you know, for SD card, NVCC_SD can be automatically switched from 3.3V to 1.8V, BUT for WiFi card, the swtich can't be performed, so we should do it manually. We have 2 way to get the purpose: software or hardware.
---software
From above DCDC schematic , you can know default is 3.3V(when SD1_VSELECT=0), we should let NVCC_SD=1.8V(SD1_VSLECT=1). So we can multiplex GPIO1_IO05 pin to be GPIO1_IO05 signal(not current SD1_VSELECT signal), and configure it to be internal pull-up, which ensure the line's level is HIGH. Below is for you reference:
(1) changing iomux node in imx6ul-14x14-evk.dtsi
&iomuxc {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_hog>;
pinctrl_hog: hoggrp {
fsl,pins = <
MX6UL_PAD_GPIO1_IO05__GPIO1_IO05 0x17059
>;
};
(2) Removing default IOMUX of the pin
Please REMOVE 'MX6UL_PAD_GPIO1_IO05__USDHC1_VSELECT' line from pinctrl_usdhc1 node!
......
pinctrl_usdhc1: usdhc1grp {
fsl,pins = <
MX6UL_PAD_SD1_CMD__USDHC1_CMD 0x17059
MX6UL_PAD_SD1_CLK__USDHC1_CLK 0x10071
MX6UL_PAD_SD1_DATA0__USDHC1_DATA0 0x17059
MX6UL_PAD_SD1_DATA1__USDHC1_DATA1 0x17059
MX6UL_PAD_SD1_DATA2__USDHC1_DATA2 0x17059
MX6UL_PAD_SD1_DATA3__USDHC1_DATA3 0x17059
MX6UL_PAD_UART1_RTS_B__GPIO1_IO19 0x17059 /* SD1 CD */
MX6UL_PAD_GPIO1_IO05__USDHC1_VSELECT 0x17059 /* SD1 VSELECT */
MX6UL_PAD_GPIO1_IO09__GPIO1_IO09 0x17059 /* SD1 RESET */
>;
};
---Hardware
Change above DCDC output to be 1.8V. like below.
If you change DCDC output like above, software don't need to be modify, default bsp is OK.
3. Removing no-1-8-v from usdhc1 node
It means , now SD1 IOlevel is 1.8V, we can make it speed up. due to hardware limitation, SD1 max speed is limited to max 132MHz. so your wifi module speed can get to the value.
in imx6ull.dtsi, we can see the limitaion.
&usdhc1 {
compatible = "fsl,imx6ull-usdhc", "fsl,imx6sx-usdhc";
assigned-clocks = <&clks IMX6UL_CLK_USDHC1_SEL>, <&clks IMX6UL_CLK_USDHC1>;
assigned-clock-parents = <&clks IMX6UL_CLK_PLL2_PFD2>;
assigned-clock-rates = <0>, <132000000>;
};
[Note]
-- WiFi SD_VIO
Before your test , don't forget to set SD_VIO to be 1.8V on WiFi module side, otherwise, IO level will mismatch, communication will fail.
--If you use software to change NVCC_SD, you can measure GPIO1_IO05 output to check if it is HIGH, otherwise, you can control it on linux command line using GPIO operation method.
OK, try above stesp, please!
Have a good day!
Regards,
weidong
