Commit
290ffe5788 (imx8m: fix reading of DDR4 MR registers) lifted a
private definition of lpddr4_mr_read() from imx8mm-cl-iot-gate board
code to drivers/ddr/imx/imx8m/ddrphy_utils.c, because that version
actually seems to work in practice.
However, commit
99c7cc58e1 (ddr: imx: Add i.MX9 DDR controller driver)
reintroduced the broken version in drivers/ddr/imx/imx8m/ddr_init.c,
copied most of the rest of ddrphy_utils.c to
drivers/ddr/imx/phy/ddrphy_utils.c, and stopped building
drivers/ddr/imx/imx8m/ddrphy_utils.c [and that file was then finally
completely removed with
7e9bd84883 (imx8m: ddrphy_utils: Remove unused
file)].
I assume this must have broken the imx8mm-cl-iot-gate board, at least
those that have not had their eeprom programmed with the proper
information. It certainly did break our out-of-tree board which always
reads back the ID register and uses that for a sanity check.
So apply the fix from
290ffe5788 once again.
Fixes:
99c7cc58e1 (ddr: imx: Add i.MX9 DDR controller driver)
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Fabio Estevam <festevam@denx.de>
tmp = reg32_read(DRC_PERF_MON_MRR0_DAT(0));
} while ((tmp & 0x8) == 0);
tmp = reg32_read(DRC_PERF_MON_MRR1_DAT(0));
- tmp = tmp & 0xff;
reg32_write(DRC_PERF_MON_MRR0_DAT(0), 0x4);
+ while (tmp) { //try to find a significant byte in the word
+ if (tmp & 0xff) {
+ tmp &= 0xff;
+ break;
+ }
+ tmp >>= 8;
+ }
return tmp;
}