On Sun, 9 Mar 2025 07:31:42 +0100 Jernej Skrabec <[email protected]> wrote:
Hi Jernej, thanks for keeping digging into this long-standing problem! > Since there is quite a few possible DRAM configurations in terms of bus > width, rank and rows and columns count, size detection algorithm must be > very careful not to test combination which would be bigger than H616 is > actually capable of handling. > > Ideally, we should always detect memory aliasing, even for 4 GB memory > size, which is the maximum amount of memory that H616 is capable of > handling. For this reason, we have to configure minimum amount of > supported rows when testing for columns and vice versa. This way test > code will never step out of 4 GB boundary. > > While at it, check for 17 rows maximum. This aligns code with BSP DRAM > driver. There is probably no such configuration which would make sense > with 4 GB memory. > > Signed-off-by: Jernej Skrabec <[email protected]> The change itself looks good to me, I have not done enough tests myself to confirm its reliability, but I trust the reports from others who were more affected by this. Reviewed-by: Andre Przywara <[email protected]> Cheers, Andre > --- > arch/arm/mach-sunxi/dram_sun50i_h616.c | 20 ++++++++++++-------- > 1 file changed, 12 insertions(+), 8 deletions(-) > > diff --git a/arch/arm/mach-sunxi/dram_sun50i_h616.c > b/arch/arm/mach-sunxi/dram_sun50i_h616.c > index b3554cc64bf5..6f84e59e39cd 100644 > --- a/arch/arm/mach-sunxi/dram_sun50i_h616.c > +++ b/arch/arm/mach-sunxi/dram_sun50i_h616.c > @@ -1363,7 +1363,7 @@ static void mctl_auto_detect_rank_width(const struct > dram_para *para, > static void mctl_auto_detect_dram_size(const struct dram_para *para, > struct dram_config *config) > { > - unsigned int shift; > + unsigned int shift, cols, rows; > > /* max. config for columns, but not rows */ > config->cols = 11; > @@ -1373,23 +1373,27 @@ static void mctl_auto_detect_dram_size(const struct > dram_para *para, > shift = config->bus_full_width + 1; > > /* detect column address bits */ > - for (config->cols = 8; config->cols < 11; config->cols++) { > - if (mctl_mem_matches(1ULL << (config->cols + shift))) > + for (cols = 8; cols < 11; cols++) { > + if (mctl_mem_matches(1ULL << (cols + shift))) > break; > } > - debug("detected %u columns\n", config->cols); > + debug("detected %u columns\n", cols); > > /* reconfigure to make sure that all active rows are accessible */ > - config->rows = 18; > + config->cols = 8; > + config->rows = 17; > mctl_core_init(para, config); > > /* detect row address bits */ > shift = config->bus_full_width + 4 + config->cols; > - for (config->rows = 13; config->rows < 18; config->rows++) { > - if (mctl_mem_matches(1ULL << (config->rows + shift))) > + for (rows = 13; rows < 17; rows++) { > + if (mctl_mem_matches(1ULL << (rows + shift))) > break; > } > - debug("detected %u rows\n", config->rows); > + debug("detected %u rows\n", rows); > + > + config->cols = cols; > + config->rows = rows; > } > > static unsigned long mctl_calc_size(const struct dram_config *config)
