In the case if the 'dram_para' struct does not specify the exact bus
width or chip density, just use a trial and error method to find a
usable configuration.
Because all the major bugs in the DRAM initialization sequence are
now hopefully fixed, it should be safe to re-initialize the DRAM
controller multiple times until we get it configured right. The
original Allwinner's boot0 bootloader also used a similar
autodetection trick.
The DDR3 spec contains the package pinout and addressing table for
different possible chip densities. It appears to be impossible to
distinguish between a single chip with 16 I/O data lines and a pair
of chips with 8 I/O data lines in the case if they provide the same
storage capacity. Because a single 16-bit chip has a higher density
than a pair of equivalent 8-bit chips, it has stricter refresh timings.
So in the case of doubt, we assume that 16-bit chips are used.
Additionally, only Allwinner A20 has all A0-A15 address lines and
can support densities up to 8192. The older Allwinner A10 and
Allwinner A13 can only support densities up to 4096.
We deliberately leave out DDR2, dual-rank configurations and the
special case of a 8-bit chip with density 8192. None of these
configurations seem to have been ever used in real devices. And no
new devices are likely to use these exotic configurations (because
only up to 2GB of RAM can be populated in any case).
This DRAM autodetection feature potentially allows to have a single
low performance fail-safe DDR3 initialiazation for a universal single
bootloader binary, which can be compatible with all Allwinner
A10/A13/A20 based devices (if the ifdefs are replaced with a runtime
SoC type detection).
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>
The write recovery time is 15ns for all JEDEC DDR3 speed bins. And
instead of hardcoding it to 10 cycles, it is possible to set tighter
timings based on accurate calculations. For example, DRAM clock
frequencies up to 533MHz need only 8 cycles for write recovery.
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>
All the known Allwinner A10/A13/A20 devices are using just single rank
DDR3 memory. So don't pretend that we support DDR2 or more than one
rank, because nobody could ever test these configurations for real and
they are likely broken. Support for these features can be added back
in the case if such hardware actually exists.
As part of this code cleanup, also replace division by 1024 with
division by 1000 for the refresh timing calculations. This allows
to use the original non-skewed tRFC timing table from the DRR3 spec
and make code less confusing.
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>
The hardware DQS gate training is a bit unreliable and does not
always find the best delay settings.
So we introduce a 32-bit 'dqs_gating_delay' variable, where each
byte encodes the DQS gating delay for each byte lane. The delay
granularity is 1/4 cycle.
Also we allow to enable the active DQS gating window mode, which
works better than the passive mode in practice. The DDR3 spec
says that there is a 0.9 cycles preamble and 0.3 cycle postamble.
The DQS window has to be opened during preamble and closed during
postamble. In the passive window mode, the gating window is opened
and closed by just using the gating delay settings. And because
of the 1/4 cycle delay granularity, accurately hitting the 0.3
cycle long postamble is a bit tough. In the active window mode,
the gating window is auto-closing with the help of monitoring
the DQS line, which relaxes the gating delay accuracy requirements.
But the hardware DQS gate training is still performed in the passive
window mode. It is a more strict test, which is reducing the results
variance compared to the training with active window mode.
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>
It is going to be useful in more than one place.
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>
The stale error status should be cleared for all sun4i/sun5i/sun7i
hardware and not just for sun7i. Also there are two types of DQS
gate training errors ("found no result" and "found more than one
possible result"). Both are handled now.
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>
This configures the PLL5P clock frequency to something in the ballpark
of 1GHz and allows more choices for MBUS and G2D clock frequency
selection (using their own divisors). In particular, it enables the use
of 2/3 clock speed ratio between MBUS and DRAM.
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>
The sun5i hardware (Allwinner A13) introduced configurable MBUS clock
speed. Allwinner A13 uses only 16-bit data bus width to connect the
external DRAM, which is halved compared to the 32-bit data bus of sun4i
(Allwinner A10), so it does not make much sense to clock a wider
internal bus at a very high speed. The Allwinner A13 manual specifies
300 MHz MBUS clock speed limit and 533 MHz DRAM clock speed limit. Newer
sun7i hardware (Allwinner A20) has a full width 32-bit external memory
interface again, but still keeps the MBUS clock speed configurable.
Clocking MBUS too low inhibits memory performance and one has to find
the optimal MBUS/DRAM clock speed ratio, which may depend on many
factors:
http://linux-sunxi.org/A10_DRAM_Controller_Performance
This patch introduces a new 'mbus_clock' parameter for the 'dram_para'
struct and uses it as a desired MBUS clock speed target. If 'mbus_clock'
is not set, 300 MHz is used by default to match the older hardcoded
settings.
PLL5P and PLL6 are both evaluated as possible clock sources. Preferring
the one, which can provide higher clock frequency that is lower or
equal to the 'mbus_clock' target. In the case of a tie, PLL5P has
higher priority.
Attempting to set the MBUS clock speed has no effect on sun4i, but does
no harm either.
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>
The DRAM controller allows to configure impedance either by using the
calibration against an external high precision 240 ohm resistor, or
by skipping the calibration and loading pre-defined data. The DRAM
controller register guide is available here:
http://linux-sunxi.org/A10_DRAM_Controller_Register_Guide#SDR_ZQCR0
The new code supports both of the impedance configuration modes:
- If the higher bits of the 'zq' parameter in the 'dram_para' struct
are zero, then the lowest 8 bits are used as the ZPROG value, where
two divisors encoded in lower and higher 4 bits. One divisor is
used for calibrating the termination impedance, and another is used
for the output impedance.
- If bits 27:8 in the 'zq' parameters are non-zero, then they are
used as the pre-defined ZDATA value instead of performing the ZQ
calibration.
Two lowest bits in the 'odt_en' parameter enable ODT for the DQ and DQS
lines individually. Enabling ODT for both DQ and DQS means that the
'odt_en' parameter needs to be set to 3.
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Siarhei Siamashka
Hans de Goede
Ian Campbell