Hi Graham,
-----Original Message----- From: Graham Moore [mailto:grmoore@opensource.altera.com] Sent: Tuesday, June 23, 2015 7:37 AM To: Vikas MANOCHA Cc: Stefan Roese; u-boot@lists.denx.de; dinguyen@opensource.altera.com; jteki@openedev.com Subject: Re: [PATCH RESEND 0/7] spi: cadence_qspi: optimize & fix indirect rd-writes
On 06/22/2015 06:31 PM, Vikas MANOCHA wrote: ...
The point is if after applying above mentioned patch (...: fix indirect read/write start address), Read/write are working fine, then trigger_base value of 0xFFA00_0000 should also work fine. Can you please modify the trigger_base value from 0x0 to 0xFFA0_0000 in Socfpga.dtsi & check. If it works, it would mean both (socfpga & stv0991) are behaving same.
No. With this change, the "sf read" command crashes / hangs on the SoCFPGA board.
Ok, I don't know why socfpga is not working with trigger_base to be
0xFFA0_0000.
Normally it should work, Graham also thinks the same, Let's wait for his
discussion with the Altera designers.
Wait a minute, on SoCFPGA, the flashbase is 0xffa00000, and the trigger base is 0x00000000. The point of having a different address was that they needed to be different on SoCFPGA, right?
As for why they're different, the Altera Cyclone5 SoCFPGA has a complex multilevel interconnect where the QSPI is three levels down, and is the only slave of an AHB master. At that level of the interconnect, the base address has long been stripped off, it was used to select down to the final master. The QSPI is the only thing on that AHB bus, so its address is zero. Or at least that's how I understand it.
If we check the code for reading/writing to the FIFO/SRAM of the controller, complete base address is being used. Which means CPU is using address 0xFFA0_0000, so does not seems like base address is stripped off. It is only for the trigger address which needs programming to 0x0 ?
Regardless, it is something specific to socfpga architecture & should not be part of cadence qspi driver.
Rgds, Vikas
-Graham