Hello,
We have accessed EIM write and read in u-boot in IMX6Quad processor, where we have got a turn around time of 230ns.
The scope image for configuration data bus Data 0-16 is
EIM_CS0GCR1 = 0x00010081
EIM_CS0GCR2 = 0x00000000
EIM_CS0RCR1 = 0x02000000
EIM_CS0RCR2 = 0x00000000
EIM_CS0WCR1 = 0x02000000
EIM_CS0WCR2 = 0x00000000
Where the turn around time is not in range as we expected, so we opted for IMX6QuadPlus processor where internal bus frequency is higher and faster. But the turn around time here is 330ns,100ns more than the IMX6Quad processor.
The scope image for configuration data bus Data 16-31 in IMX6QP SabreSD board is
EIM_CS0GCR1 = 0x00020081
EIM_CS0GCR2 = 0x00000000
EIM_CS0RCR1 = 0x02000000
EIM_CS0RCR2 = 0x00000000
EIM_CS0WCR1 = 0x02000000
EIM_CS0WCR2 = 0x00000000
Why performance drop from IMX6Q to IMX6QP processor ?
Any bus registers configurations need to be changed for better performance to achieve turn around time less than 100ns?
thanks ,
uday
Hi Igor
I could not find EIM apb_slave index in imx6 reference manaul. Could you please share me the apb_slave index of EIM and its QoS default value.
thanks,
uday
seems it is GPV_3 index=82, default value=2 as for
other peripherals.
~igor
Hi Igor,
I try to write 0x03 and read back value is 0.
In data sheet its given as reserved ,have any idea to write and read and need to take care anything?
thanks,
uday
Hi Igor
For the
Write QoS: "0x00C4_9104" what is the minmum and maximum value can be written?
thanks
uday
Hi uday
it is 4 bit wide and description can be found in arm NIC-301 Technical Reference Manual
Best regards
igor
Hi uday
delays are introduced mostly by bus arbiters nic301 and since i.MX6QuadPlus
has more complex architecture, it may have more delays. Difference is described in
EB810 i.MX6Dual/6Quad and i.MX6DualPlus/6QuadPlus Applications Processor Comparison
http://cache.nxp.com/docs/en/engineering-bulletin/EB810.pdf
In general one can try to tweak QoS (EIM connected to GPV_3) usingsect.47.3.3.1 NIC-301 QoS
Reference Manual.
Best regards
igor
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