[U-Boot] imx: add i.MX8MQ EVK support

[Jacky Bai]

> Sent: Monday, August 19, 2019 2:25 PM
> To: Troy Kisky <troy.kisky at boundarydevices.com>; Fabio Estevam
> <fabio.estevam at nxp.com>; Stefano Babic <sbabic at denx.de>;
> u-boot at lists.denx.de; Jacky Bai <ping.bai at nxp.com>
> Subject: RE: imx: add i.MX8MQ EVK support
> 
> Loop Jacky who has more knowledge in the ddr stuff.
> 
> > Subject: re: imx: add i.MX8MQ EVK support
> >
> > Hi Peng
> >
> > In spl.c you have
> >
> > _________
> > static void spl_dram_init(void)
> > {
> > 	/* ddr init */
> > 	if ((get_cpu_rev() & 0xfff) == CHIP_REV_2_1)
> > 		ddr_init(&dram_timing);
> > 	else
> > 		ddr_init(&dram_timing_b0);
> > }
> >
> > _________
> >
> > Could you explain why this is dependent on chip rev ?

It is due an errata in DDR PHY, for chip Rev lower than 2.1, set point < 667mts can NOT be supported

> >
> > It it just the extra frequency in lpddr4_timing.c ?
> >
> > __________
> > 	{
> > 		/* P1 100mts 1D */
> > 		.drate = 100,
> > 		.fw_type = FW_1D_IMAGE,
> > 		.fsp_cfg = lpddr4_fsp2_cfg,
> > 		.fsp_cfg_num = ARRAY_SIZE(lpddr4_fsp2_cfg),
> > 	},
> > _________
> >
> >
> > Will other i.MX8MQ boards also need this check ?
> >

For most of the customer board, I think the chip Rev is 2.1, so no need such check.

> >
> > Thanks
> > Troy