The Zynq has a bug where the L2 cache will return invalid data in some
circumstances unless the L2C_RAM register is set to 0x00020202 before the first
enabling of the L2 cache.
The Xilinx-recommended solution to this problem is to ensure that early one of
the earlier bootstages correctly initialize L2C_RAM, however, this issue wasn't
discovered and fixed until after their EDK/SDK 14.4 release. For systems built
prior to that, and which lack field-upgradable bootloaders, this issue still
exists and silent data corruption can be seen in the wild.
Fix these systems by ensuring L2C_RAM is properly initialized at the
earliest convenient moment prior to the L2 being brought up, which is
when the SLCR is first mapped.
The Zynq bug is described in more detail by Xilinx AR# 54190 as quoted
below.
Xilinx AR# 54190
http://www.xilinx.com/support/answers/54190.htm
Captured on 2014-09-24 14:43 -0500
= Description =
For proper L2 cache operation, the user code must program the
slcr.L2C_RAM register (address 0xF800_0A1C) to the value of
0x0002_0202 before enabling the L2 cache. The reset value
(0x0001_0101) might cause, very infrequently, the L2 cache to return
invalid data.
= Solution =
It is up to the user code (FSBL or other user code) to set the
slcr.L2C_RAM register to the value 0x0002_0202 before enabling the L2
cache.
Note: The L2 cache is disabled after reset and is not enabled by the
BootROM.
Note: The slcr.l2C_RAM register was previously reserved. It is added
in the Zynq-7000 AP SoC Technical Reference Manual (TRM) v1.5 as
"Reserved".
Thanks to Jaeden Amero for initial debugging and triage efforts.
Signed-off-by: Josh Cartwright <joshc@ni.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
The SLCR is unconditionally unlocked early on boot in zynq_slcr_init()
and not ever re-locked. As such, it is not necessary to explicitly unlock in
the restart codepath.
Signed-off-by: Josh Cartwright <joshc@ni.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
By making use of the restart_handler chain mechanism, the SLCR-based
reset mechanism can be prioritized amongst other mechanisms available on
a particular board.
Choose a default high-ish priority of 192 for this restart mechanism.
Signed-off-by: Josh Cartwright <joshc@ni.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Based on
"mfd: syscon: Decouple syscon interface from platform devices"
(sha1: bdb0066df9)
SLCR driver can use syscon/regmap drivers directly.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Avoid races and add synchronisation between the arch specific
kill and die routines.
The same synchronisation issue was fixed on IMX platform
by this commit:
"ARM: imx: fix sync issue between imx_cpu_die and imx_cpu_kill"
(sha1: 2f3edfd7e2)
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Provide information through SOC_BUS to user space.
Silicon revision is provided through devcfg device.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Use zynq_slcr_read/write helper functions for reg access
instead of readl/writel.
Also use regmap when it is ready.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
The pointer doesn't need to be passed around any more.
Make it static.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Split the slcr into an early part for unlocking and cpu starting
and a later syscon driver.
Also add "syscon" compatible property for slcr.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
zynq_slcr_cpu_start/stop() ignored the current register state when
writing to a register. Fixing this by implementing proper
read-modify-write.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Use a common naming scheme for register offset #defines:
Some of those used a '_OFFSET' suffix to distinguish them from others.
This scheme is used for all register offsets now.
Separate the register offset #defines from others and sort them in
increasing order.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Migrate the Zynq platform and its drivers to use the new clock
controller driver.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Zynq is dual core Cortex A9 which starts always
at zero. Using simple trampoline ensure long jump
to secondary_startup code.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
