On Thu, 2015-11-05 at 08:23 +0000, Yuantian Tang wrote:
Hi Jocke,
we achieved deep sleep mode that did exactly what you asked for. If waken up from deep sleep, soc will resume from uboot and re-initialized DDR controller with contents untouched. Please refer to drivers/ddr/fsl/fsl_ddr_gen4.c and look at DEEP_SLEEP related code.
Looking at it now and it looks the same as for ddr3? Some questions though: 289 if (is_warm_boot()) { 289 /* enter self-refresh */ 290 temp_sdram_cfg = ddr_in32(&ddr->sdram_cfg_2); 291 temp_sdram_cfg |= SDRAM_CFG2_FRC_SR; 292 ddr_out32(&ddr->sdram_cfg_2, temp_sdram_cfg);
Why do you need to force SR here? The DDR RAM must already be in SR at this point? I come from CPU reset state so my DDR controller has HW default values so this does not feel safe.
293 /* do board specific memory setup */ 294 board_mem_sleep_setup(); 295 296 temp_sdram_cfg = (ddr_in32(&ddr->sdram_cfg) | SDRAM_CFG_BI); SDRAM_CFG_BI skips a lot(all?) init of DDR RAM. What if you want to change some DDR RAM timing/config due to a bug? Then you would have to force a cold start.
Do you use ECC? Seems to be some issues with ECC if you skip D_INIT
Jocke
Regards, Yuantian
-----Original Message----- From: Joakim Tjernlund [mailto:joakim.tjernlund@transmode.se] Sent: Thursday, November 05, 2015 4:04 PM To: Sun York-R58495 yorksun@freescale.com; u-boot@lists.denx.de Cc: curt@cumulusnetworks.com; Sharma Bhupesh-B45370 bhupesh.sharma@freescale.com; trini@konsulko.com; l.majewski@samsung.com; Tang Yuantian-B29983 Yuantian.Tang@freescale.com; Kushwaha Prabhakar-B32579 prabhakar@freescale.com; Liu Shengzhou-B36685 Shengzhou.Liu@freescale.com; yamada.m@jp.panasonic.com Subject: Re: [PATCH v1 0/7] Enable high speed and heavy load for DDR4 for LSCH3
On Wed, 2015-11-04 at 10:03 -0800, York Sun wrote:
This patch set revises the DDR driver to support higher speed for DDR4 under heavy load (two dual-rank DIMMs) for four-chipselect interleaving. Single quad-rank DIMM is not supported yet.
Hi York
Seeing these patches reminds me about something I have been mening to ask, Is it possible init the ddr controller/ddr ram (using ECC also) but still retain (parts of) memory contents?
I am looking at keeping data at the end of memory when performing a warm start, but still init the controll/ddr ram (without D_INIT set). This way one could pick up any changes to DDR timing if needed. Before reboot, ddr ram is set to Self Refresh(SR).
Jocke