diff mbox

[U-Boot] Revert "common/memsize.c: Simplify RAM size detection"

Message ID 1455053911-7530-1-git-send-email-hdegoede@redhat.com
State Accepted
Commit cc8d698fabf072f49ef4dfb2cfdbe0f57d54af81
Delegated to: Tom Rini
Headers show

Commit Message

Hans de Goede Feb. 9, 2016, 9:38 p.m. UTC
This commit breaks bootup on sunxi boards, the get stuck
when running the main u-boot binary at:

CPU:   Allwinner H3 (SUN8I)
I2C:   ready
DRAM:

This reverts commit 8e7cba048baae68ee0916a8f52b4304277328d5e.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 common/memsize.c | 47 ++++++++++++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 21 deletions(-)

Comments

Eddy Petrișor Feb. 10, 2016, 6:11 a.m. UTC | #1
Hi Hans,

I sent a fixup patch yesterday (I managed somehow to send an outdated
patch), did you try the fixup patch?

http://lists.denx.de/pipermail/u-boot/2016-February/245080.html
Pe 9 feb. 2016 11:38 p.m., "Hans de Goede" <hdegoede@redhat.com> a scris:

> This commit breaks bootup on sunxi boards, the get stuck
> when running the main u-boot binary at:
>
> CPU:   Allwinner H3 (SUN8I)
> I2C:   ready
> DRAM:
>
> This reverts commit 8e7cba048baae68ee0916a8f52b4304277328d5e.
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  common/memsize.c | 47 ++++++++++++++++++++++++++---------------------
>  1 file changed, 26 insertions(+), 21 deletions(-)
>
> diff --git a/common/memsize.c b/common/memsize.c
> index 5c0d279..0fb9ba5 100644
> --- a/common/memsize.c
> +++ b/common/memsize.c
> @@ -33,28 +33,38 @@ long get_ram_size(long *base, long maxsize)
>         long           size;
>         int            i = 0;
>
> -       for (cnt = (maxsize / sizeof(long)) >> 1; cnt >= 0; cnt >>= 1) {
> +       for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) {
>                 addr = base + cnt;      /* pointer arith! */
>                 sync();
> -               save[i] = *addr;
> +               save[i++] = *addr;
>                 sync();
> -               if (cnt) {
> -                       i++;
> -                       *addr = ~cnt;
> -               } else {
> -                       *addr = 0;
> -               }
> +               *addr = ~cnt;
>         }
>
> +       addr = base;
> +       sync();
> +       save[i] = *addr;
> +       sync();
> +       *addr = 0;
> +
>         sync();
> -       cnt = 0;
> -       do {
> +       if ((val = *addr) != 0) {
> +               /* Restore the original data before leaving the function.
> */
> +               sync();
> +               *addr = save[i];
> +               for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
> +                       addr  = base + cnt;
> +                       sync();
> +                       *addr = save[--i];
> +               }
> +               return (0);
> +       }
> +
> +       for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
>                 addr = base + cnt;      /* pointer arith! */
>                 val = *addr;
> -               *addr = save[i--];
> -               sync();
> -               if (((cnt == 0) && (val != 0)) ||
> -                   ((cnt != 0) && (val != ~cnt))) {
> +               *addr = save[--i];
> +               if (val != ~cnt) {
>                         size = cnt * sizeof(long);
>                         /*
>                          * Restore the original data
> @@ -64,16 +74,11 @@ long get_ram_size(long *base, long maxsize)
>                              cnt < maxsize / sizeof(long);
>                              cnt <<= 1) {
>                                 addr  = base + cnt;
> -                               *addr = save[i--];
> +                               *addr = save[--i];
>                         }
>                         return (size);
>                 }
> -
> -               if (cnt)
> -                       cnt = cnt << 1;
> -               else
> -                       cnt = 1;
> -       } while (cnt < maxsize / sizeof(long));
> +       }
>
>         return (maxsize);
>  }
> --
> 2.5.0
>
>
Hans de Goede Feb. 10, 2016, 8:20 a.m. UTC | #2
Hi,

On 10-02-16 07:11, Eddy Petrișor wrote:
> Hi Hans,
>
> I sent a fixup patch yesterday (I managed somehow to send an outdated
> patch),

Ah I did not notice that one.

> did you try the fixup patch?

I just did try it, same results as Hannes the hang is gone, but now
the RAM size is misdedetected (it detects 2 GiB on a 1 GiB board).

It seems this code was as it was for a reason and that a revert
of your simplification is probably the best solution.

Regards,

Hans




>
> http://lists.denx.de/pipermail/u-boot/2016-February/245080.html
> Pe 9 feb. 2016 11:38 p.m., "Hans de Goede" <hdegoede@redhat.com> a scris:
>
>> This commit breaks bootup on sunxi boards, the get stuck
>> when running the main u-boot binary at:
>>
>> CPU:   Allwinner H3 (SUN8I)
>> I2C:   ready
>> DRAM:
>>
>> This reverts commit 8e7cba048baae68ee0916a8f52b4304277328d5e.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>   common/memsize.c | 47 ++++++++++++++++++++++++++---------------------
>>   1 file changed, 26 insertions(+), 21 deletions(-)
>>
>> diff --git a/common/memsize.c b/common/memsize.c
>> index 5c0d279..0fb9ba5 100644
>> --- a/common/memsize.c
>> +++ b/common/memsize.c
>> @@ -33,28 +33,38 @@ long get_ram_size(long *base, long maxsize)
>>          long           size;
>>          int            i = 0;
>>
>> -       for (cnt = (maxsize / sizeof(long)) >> 1; cnt >= 0; cnt >>= 1) {
>> +       for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) {
>>                  addr = base + cnt;      /* pointer arith! */
>>                  sync();
>> -               save[i] = *addr;
>> +               save[i++] = *addr;
>>                  sync();
>> -               if (cnt) {
>> -                       i++;
>> -                       *addr = ~cnt;
>> -               } else {
>> -                       *addr = 0;
>> -               }
>> +               *addr = ~cnt;
>>          }
>>
>> +       addr = base;
>> +       sync();
>> +       save[i] = *addr;
>> +       sync();
>> +       *addr = 0;
>> +
>>          sync();
>> -       cnt = 0;
>> -       do {
>> +       if ((val = *addr) != 0) {
>> +               /* Restore the original data before leaving the function.
>> */
>> +               sync();
>> +               *addr = save[i];
>> +               for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
>> +                       addr  = base + cnt;
>> +                       sync();
>> +                       *addr = save[--i];
>> +               }
>> +               return (0);
>> +       }
>> +
>> +       for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
>>                  addr = base + cnt;      /* pointer arith! */
>>                  val = *addr;
>> -               *addr = save[i--];
>> -               sync();
>> -               if (((cnt == 0) && (val != 0)) ||
>> -                   ((cnt != 0) && (val != ~cnt))) {
>> +               *addr = save[--i];
>> +               if (val != ~cnt) {
>>                          size = cnt * sizeof(long);
>>                          /*
>>                           * Restore the original data
>> @@ -64,16 +74,11 @@ long get_ram_size(long *base, long maxsize)
>>                               cnt < maxsize / sizeof(long);
>>                               cnt <<= 1) {
>>                                  addr  = base + cnt;
>> -                               *addr = save[i--];
>> +                               *addr = save[--i];
>>                          }
>>                          return (size);
>>                  }
>> -
>> -               if (cnt)
>> -                       cnt = cnt << 1;
>> -               else
>> -                       cnt = 1;
>> -       } while (cnt < maxsize / sizeof(long));
>> +       }
>>
>>          return (maxsize);
>>   }
>> --
>> 2.5.0
>>
>>
>
Eddy Petrișor Feb. 10, 2016, 9 a.m. UTC | #3
2016-02-10 10:20 GMT+02:00 Hans de Goede <hdegoede@redhat.com>:
> Hi,
>
> On 10-02-16 07:11, Eddy Petrișor wrote:
>>
>> Hi Hans,
>>
>> I sent a fixup patch yesterday (I managed somehow to send an outdated
>> patch),
>
>
> Ah I did not notice that one.
>
>> did you try the fixup patch?
>
>
> I just did try it, same results as Hannes the hang is gone, but now
> the RAM size is misdedetected (it detects 2 GiB on a 1 GiB board).
>
> It seems this code was as it was for a reason and that a revert
> of your simplification is probably the best solution.

OK, agreed, that makes sense. My buggy HW (DDR unstable) doesn't help.

I will probably rework the patch and target the v2016.05 release.
Wolfgang Denk Feb. 10, 2016, 9:36 a.m. UTC | #4
Dear Hans,

In message <56BAF2B1.3040507@redhat.com> you wrote:
> 
> It seems this code was as it was for a reason and that a revert
> of your simplification is probably the best solution.

Indeed. Over the past 15 years I have seen several attempts to
improve or simplify the mesize code.  Most did not make it into
mainline as they worked for the poster, but caused problems on some
other boards.

We had a similar "simplification" in 2012, see commit b8496cce and
revert in 3ab270d5, but all these attempts caused problems of some
kind, so the basic structure of the code is still exactly the same
as in the original version of 2004 (commit c83bf6a2).

Probably this is just Perfect Code (TM) which cannot improved further
:-)

Best regards,

Wolfgang Denk
Tom Rini Feb. 10, 2016, 1:35 p.m. UTC | #5
On Tue, Feb 09, 2016 at 10:38:31PM +0100, Hans de Goede wrote:

> This commit breaks bootup on sunxi boards, the get stuck
> when running the main u-boot binary at:
> 
> CPU:   Allwinner H3 (SUN8I)
> I2C:   ready
> DRAM:
> 
> This reverts commit 8e7cba048baae68ee0916a8f52b4304277328d5e.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Applied to u-boot/master, thanks!
diff mbox

Patch

diff --git a/common/memsize.c b/common/memsize.c
index 5c0d279..0fb9ba5 100644
--- a/common/memsize.c
+++ b/common/memsize.c
@@ -33,28 +33,38 @@  long get_ram_size(long *base, long maxsize)
 	long           size;
 	int            i = 0;
 
-	for (cnt = (maxsize / sizeof(long)) >> 1; cnt >= 0; cnt >>= 1) {
+	for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) {
 		addr = base + cnt;	/* pointer arith! */
 		sync();
-		save[i] = *addr;
+		save[i++] = *addr;
 		sync();
-		if (cnt) {
-			i++;
-			*addr = ~cnt;
-		} else {
-			*addr = 0;
-		}
+		*addr = ~cnt;
 	}
 
+	addr = base;
+	sync();
+	save[i] = *addr;
+	sync();
+	*addr = 0;
+
 	sync();
-	cnt = 0;
-	do {
+	if ((val = *addr) != 0) {
+		/* Restore the original data before leaving the function. */
+		sync();
+		*addr = save[i];
+		for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
+			addr  = base + cnt;
+			sync();
+			*addr = save[--i];
+		}
+		return (0);
+	}
+
+	for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
 		addr = base + cnt;	/* pointer arith! */
 		val = *addr;
-		*addr = save[i--];
-		sync();
-		if (((cnt == 0) && (val != 0)) ||
-		    ((cnt != 0) && (val != ~cnt))) {
+		*addr = save[--i];
+		if (val != ~cnt) {
 			size = cnt * sizeof(long);
 			/*
 			 * Restore the original data
@@ -64,16 +74,11 @@  long get_ram_size(long *base, long maxsize)
 			     cnt < maxsize / sizeof(long);
 			     cnt <<= 1) {
 				addr  = base + cnt;
-				*addr = save[i--];
+				*addr = save[--i];
 			}
 			return (size);
 		}
-
-		if (cnt)
-			cnt = cnt << 1;
-		else
-			cnt = 1;
-	} while (cnt < maxsize / sizeof(long));
+	}
 
 	return (maxsize);
 }