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ARM: dts: keystone: k2l: fix kernel crash when clk_ignore_unused is not in bootargs 

Currently kernel crash randomly when K2L EVM is booted without
clk_ignore_unused in the bootargs. This workaround is not needed
on other K2 devices such as K2HK and K2E and with this fix, we can
remove the workaround altogether. netcp driver on K2L uses linked
ram on OSR (On chip Static RAM) and requires the clock to this peripheral
enabled for proper functioning. This is the reason for the kernel crash.
So add the clock node to fix this issue.

While at it, remove the workaround documentation as well.

With the fix applied, clk_summary dump shows the clock to OSR enabled.

cat /sys/kernel/debug/clk/clk_summary
 ------cut--------------
   tcp3d-1                   0            0   399360000          0 0
   tcp3d-0                   0            0   399360000          0 0
   osr                       1            1   399360000          0 0
   fftc-0                    0            0   399360000          0 0
 -----cut----------------
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>
This commit is contained in:
Murali Karicheri 2015-11-23 10:35:25 -08:00 committed by Santosh Shilimkar
parent f7f2bccd1f
commit 17e846aa39
2 changed files with 1 additions and 19 deletions
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18
Documentation/arm/keystone/Overview.txt
View File

@ -49,24 +49,6 @@ specified through DTS. Following are the DTS used:-
The device tree documentation for the keystone machines are located at
Documentation/devicetree/bindings/arm/keystone/keystone.txt
Known issues & workaround
-------------------------
Some of the device drivers used on keystone are re-used from that from
DaVinci and other TI SoCs. These device drivers may use clock APIs directly.
Some of the keystone specific drivers such as netcp uses run time power
management API instead to enable clock. As this API has limitations on
keystone, following workaround is needed to boot Linux.
Add 'clk_ignore_unused' to the bootargs env variable in u-boot. Otherwise
clock frameworks will try to disable clocks that are unused and disable
the hardware. This is because netcp related power domain and clock
domains are enabled in u-boot as run time power management API currently
doesn't enable clocks for netcp due to a limitation. This workaround is
expected to be removed in the future when proper API support becomes
available. Until then, this work around is needed.
Document Author
---------------
Murali Karicheri <m-karicheri2@ti.com>

2
arch/arm/boot/dts/k2l-netcp.dtsi
View File

@ -137,7 +137,7 @@ netcp: netcp@26000000 {
/* NetCP address range */
ranges = <0 0x26000000 0x1000000>;
clocks = <&papllclk>, <&clkcpgmac>, <&chipclk12>;
clocks = <&clkosr>, <&papllclk>, <&clkcpgmac>, <&chipclk12>;
dma-coherent;
ti,navigator-dmas = <&dma_gbe 0>,