[PATCH] riscv: spacemit: k1: probe dram size during boot phase.

[Simon Glass]

Hi Dan,

On Wed, 8 Jan 2025 at 05:37, Dan Carpenter <dan.carpenter at linaro.org> wrote:
>
> On Wed, Jan 08, 2025 at 12:21:18PM +0100, Heinrich Schuchardt wrote:
> > Am 8. Januar 2025 12:11:05 MEZ schrieb Yixun Lan <dlan at gentoo.org>:
> > >Hi Huan:
> > >
> > >On 16:49 Wed 08 Jan     , Huan Zhou wrote:
> > >>
> > >>
> > >..
> > >> ---
> > >remove above "---"? otherwise following commit message will be
> > >dropped during patch application..
> > >
> > >> This patch introduce improvement for get dram size on bananapi BPI-F3,
> > >> retrieving the dram size dynamically.
> > >> Have tested on bananapi BPIF3 4G and jupiter 8G.
> > >>
> > >> Signed-off-by: Huan Zhou <me at per1cycle.org>
> > >> ---
> > >>  arch/riscv/cpu/k1/dram.c | 40 ++++++++++++++++++++++++++++++++++++++--
> > >>  1 file changed, 38 insertions(+), 2 deletions(-)
> > >>
> > >> diff --git a/arch/riscv/cpu/k1/dram.c b/arch/riscv/cpu/k1/dram.c
> > >> index c477c15cbfb19f0e3a0ee72985b602f5bda352d7..095217f2a4c053f7477d62c0776bcb51e623db47 100644
> > >> --- a/arch/riscv/cpu/k1/dram.c
> > >> +++ b/arch/riscv/cpu/k1/dram.c
> > >> @@ -4,17 +4,53 @@
> > >>   */
> > >>
> > >>  #include <asm/global_data.h>
> > >> +#include <asm/io.h>
> > >>  #include <config.h>
> > >> +#include <bitfield.h>
> > >>  #include <fdt_support.h>
> > >>  #include <linux/sizes.h>
> > >>
> > >> +#define DDR_BASE 0xC0000000
> > >>  DECLARE_GLOBAL_DATA_PTR;
> > >>
> > >> +static inline u32 map_format_size(u32 val)
> > >> +{
> > >> +  u32 tmp;
> > >> +
> > >> +  if (val & 0x1 == 0)
> > >please add brackets explicitly, something like
> > >     if ((val & 0x1) == 0)
> >
> > We tend to avoid == 0 in U-Boot
> >
> > if (val & BIT(0))
> >
>
> That's reversed.
>
>         if (!(val & BIT(0)) {
>
> I have really complicated rules about when to use ! vs == 0.
> https://staticthinking.wordpress.com/2024/02/20/when-to-use-0/

I  mostly agree with that and it provides some motivation for the
conventions which have built up over the years in Linux/U-Boot/etc.

If you want to send a patch:

$ git grep 'if (ret != EFI_SUCCESS)' |wc
    864    4841   51380

I think the only place I would differ is with strcmp(), where I've got
used to 0 meaning success, like in much other code.

[..]

Regards,
SImon