On Thu, Sep 28, 2023 at 11:57 AM Andrejs Cainikovs <andrejs.cainik...@gmail.com> wrote: > > From: Andrejs Cainikovs <andrejs.cainik...@toradex.com> > > Update lpddr4 configuration and training using updated spreadsheet and > tools from NXP using data from previous spreadsheet and verified > toward datasheet: > > - MX8M_Mini_LPDDR4_RPA_v22.xlsx > - mscale_ddr_tool_v3.31_setup.exe > > The most relevant update is related to errata ERR050805: > "DRAM: Controller automatic derating logic may not work when > the LPDDR4 memory temperature is above 85 °C at initialization" > > Other relevant fixes: > - DRAMTMG7 register: corrected calculation of T_CKPDX parameter > (equal to tCKCKEH for LPDDR4) > - RANKCTL register: corrected calculations for ODTLon and ODTLoff > to follow the JEDEC specification > - ADDRMAP7 register: added support for 17-row devices > > As per errata ERR050805: > > An issue exists with the automatic derating logic of the DDR > controller that only samples the LPDDR4 MR4 register when the > Temperature Update Flag (TUF) field (MR4[7] ) is 1’b1. If the > LPDDR4 memory is initialized and starts operation above 85 °C > (MR4[2:0] > 3’b011), the MR4 Temperature Update Flag (TUF) will > not be set. The DDR Controller will therefore not automatically > adjust the memory refresh rate or de-rate memory timings based > on the LPDDR4 memory temperature. This may cause the controller > incorrectly setting the refresh period, potentially cause the > LPDDR4 memory losing data contents and lead to possible data > integrity issues above 85 °C. > > Errata provides three possible workaround options, while option 2 > is the most reasonable: > > Disable the automatic derating logic of the DDR controller and > apply fixed x2 refresh rate (0.5x refresh). This option is > suitable for designs that are expected to boot at or above 85 °C > and memory’s MR4[2:0] (Refresh Rate) DOES NOT report the following > conditions: > 3b101: 0.25x refresh, no de-rating > 3b110: 0.25x refresh, with de-rating > 3b111: SDRAM High temperature operating limit exceeded > > [1]: https://www.nxp.com/docs/en/errata/IMX8MM_0N87W.pdf > > Signed-off-by: Andrejs Cainikovs <andrejs.cainik...@toradex.com>
Reviewed-by: Fabio Estevam <feste...@gmail.com>
