Commit Graph

10 Commits

Author SHA1 Message Date
Siarhei Siamashka
94cd301988 sunxi: dram: Add 'await_bits_clear'/'await_bits_set' helper functions
The old 'await_completion' function is not sufficient, because
in some cases we want to wait for bits to be cleared, and in the
other cases we want to wait for bits to be set. So split the
'await_completion' into two new 'await_bits_clear' and
'await_bits_set' functions.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:33 +02:00
Siarhei Siamashka
cfc89b003b sunxi: dram: Do DDR3 reset in the same way on sun4i/sun5i/sun7i
The older differences were likely justified by the need to mitigate
the CKE delay timing violations on sun4i/sun5i. The CKE problem is
already resolved, so now we can use the sun7i variant of this code
everywhere.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
Siarhei Siamashka
7e40e1926a sunxi: dram: Remove broken impedance and ODT configuration code
We can safely remove it, because none of the currently supported
boards uses these features.

The existing implementation had multiple problems:
   - unnecessary code duplication between sun4i/sun5i/sun7i
   - ZQ calibration was never initiated explicitly, and could be
     only triggered by setting the highest bit in the 'zq' parameter
     in the 'dram_para' struct (this was never actually done for
     any of the known Allwinner devices).
   - even if the ZQ calibration could be started, no attempts were
     made to wait for its completion, or checking whether the
     default automatically initiated ZQ calibration is still
     in progress
   - ODT was only ever enabled on sun4i, but not on sun5i/sun7i

Additionally, SDR_IOCR was set to 0x00cc0000 only on sun4i. There
are some hints in the Rockchip Linux kernel sources, indicating
that these bits are related to the automatic I/O power down
feature, which is poorly understood on sunxi hardware at the
moment. Avoiding to set these bits on sun4i too does not seem to
have any measurable/visible impact.

The impedance and ODT configuration code will be re-introdeced in
one of the next comits.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
Siarhei Siamashka
f8e88b6837 sunxi: dram: Fix CKE delay handling for sun4i/sun5i
Before driving the CKE pin (Clock Enable) high, the DDR3 spec requires
to wait for additional 500 us after the RESET pin is de-asserted.

The DRAM controller takes care of this delay by itself, using a
configurable counter in the SDR_IDCR register. This works in the same
way on sun4i/sun5i/sun7i hardware (even the default register value
0x00c80064 is identical). Except that the counter is ticking a bit
slower on sun7i (3 DRAM clock cycles instead of 2), resulting in
longer actual delays for the same settings.

This patch configures the SDR_IDCR register for all sun4i/sun5i/sun7i
SoC variants and not just for sun7i alone. Also an explicit udelay(500)
is added immediately after DDR3 reset for extra safety. This is a
duplicated functionality. But since we don't have perfect documentation,
it may be reasonable to play safe. Half a millisecond boot time increase
is not that significant. Boot time can be always optimized later.
Preferebly by the people, who have the hardware equipment to check the
actual signals on the RESET and CKE lines and verify all the timings.

The old code did not configure the SDR_IDCR register for sun4i/sun5i,
but performed the DDR3 reset very early for sun4i/sun5i. This resulted
in a larger time gap between the DDR3 reset and the DDR3 initialization
steps and reduced the chances of CKE delay timing violation to cause
real troubles.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
Siarhei Siamashka
e626d2d446 sunxi: dram: Respect the DDR3 reset timing requirements
The RESET pin needs to be kept low for at least 200 us according
to the DDR3 spec. So just do it the right way.

This issue did not cause any visible major problems earlier, because
the DRAM RESET pin is usually already low after the board reset. And
the time gap before reaching the sunxi u-boot DRAM initialization
code appeared to be sufficient.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
Siarhei Siamashka
f257796773 sunxi: dram: Remove broken super-standby remnants
If the dram->ppwrsctl (SDR_DPCR) register has the lowest bit set to 1,
this means that DRAM is currently in self-refresh mode and retaining the
old data. Since we have no idea what to do in this situation yet, just
set this register to 0 and initialize DRAM in the same way as on any
normal reboot (discarding whatever was stored there).

This part of code was apparently used by the Allwinner boot0 bootloader
to handle resume from the so-called super-standby mode. But this
particular code got somehow mangled on the way from the boot0 bootloader
to the u-boot-sunxi bootloader and has no chance of doing anything even
remotely sane. For example:
1. in the original boot0 code we had "mctl_write_w(SDR_DPCR,
   0x16510000)" (write to the register) and in the u-boot it now looks
   like "setbits_le32(&dram->ppwrsctl, 0x16510000)" (set bits in the
   register)
2. in the original boot0 code it was issuing three commands "0x12, 0x17,
   0x13" (Self-Refresh entry, Self-Refresh exit, Refresh), but in the
   u-boot they have become "0x12, 0x12, 0x13" (Self-Refresh entry,
   Self-Refresh entry, Refresh)

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
Siarhei Siamashka
34759d74a3 sunxi: dram: Remove useless 'dramc_scan_dll_para()' function
The attempt to do DRAM parameters calibration in 'dramc_scan_dll_para()'
function by trying different DLL adjustments and using the hardware
DQS gate training result as a feedback is a great source of inspiration,
but it just can't work properly the way it is implemented now. The fatal
problem of this implementation is that the DQS gating window can be
successfully found for almost every DLL delay adjustment setup that
gets tried. Thus making it unable to see any real difference between
'good' and 'bad' settings.

Also this code was supposed to be only activated by setting the highest
bit in the 'dram_tpr3' variable of the 'dram_para' struct (per-board
dram configuration). But none of the linux-sunxi devices has ever used
it for real. Basically, this code is just a dead weight.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
Hans de Goede
f84269c5c0 sunxi: Add sun5i support
Add support for the Allwinner A13 and A10s SoCs also know as the Allwinner
sun5i family, and the A13-OLinuXinoM A13 based and r7-tv-dongle A10s based
boards.

The only differences compared to the already supported sun4i and sun7i
families are all in the DRAM controller initialization:

-Different hcpr values
-Different MBUS settings
-Some other small initialization changes

Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
2014-07-06 20:12:44 +01:00
Hans de Goede
745325a97d sunxi: Add sun4i support
Add support for the Allwinner A10 SoC also known as the Allwinner sun4i family,
and add the Cubieboard board which uses the A10 SoC.

Compared to sun7 only the DRAM controller is a bit different:
-Controller reset bits are inverted, but only for Rev. A
-Different hpcr values
-No MBUS on sun4i
-Various other initialization changes

Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
2014-07-06 20:12:44 +01:00
Ian Campbell
286c3c3a5e sunxi: add sun7i dram setup support
This patch adds DRAM initialisation support for the Allwinner A20 (sun7i)
processor. This code will not been compiled until the build is hooked up in a
later patch. It has been split out to keep the patches manageable.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Luke Leighton <lkcl@lkcl.net>
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Reviewed-by: Marek Vasut <marex@denx.de>
Cc: Tom Cubie <Mr.hipboi@gmail.com>
Reviewed-by: Tom Rini <trini@ti.com>
2014-05-25 16:12:30 +02:00