Increasing Embedded eFlash size

[nashsrg]

Hello,

As per documentation maximum size of eFlash is 512kB. Is it possible to increase size of Embedded eFlash?
For emulation if we target FPGA with more BRAM/URAM. We can support more memory as well as O.S or Firmware with more Code and data section can also be supported.

Thank You.

[imphil]

Sure. The flash size is a parameter, you can modify it as you wish. Have a look at https://github.com/lowRISC/opentitan/blob/master/hw/top_earlgrey/rtl/top_pkg.sv. Unfortunately, the banking of the flash will require a couple other changes depending on what parameters you want to choose, please give it a try and let us know if you run into problems.

[nashsrg]

I am able to increase eFLASH size to 1MB. by changing either following parameter. Observed BRAM utilization increase for u_flash_eflash module.
localparam int FLASH_BANKS=2; -> 4
OR
localparam int FLASH_PAGES_PER_BANK=256; -> 512
OR
localparam int FLASH_WORDS_PER_PAGE=128; -> 256

Do i need to change address map for eflash or any other file from firmware perspective?

[tjaychen]

I would recommend doubling the FLASH_PAGES_PER_BANK but leave the others untouched. That will remove the need to change anything in the registers. You will have to change the linker scripts to reflect this update (sorry I'm a bit out of date on exactly which one you need to change in sw/device). It's long been on my TODO list to template this module so you can pick the sizes you want..hopefully that will happen soon.

…

On Mon, Aug 31, 2020 at 4:13 AM nashsrg ***@***.***> wrote: So to increase Flash size from 512kB to 1MB, which of the following parameter i need to change.I am not sure how the RTL use following parameter for eflash implementation. localparam int FLASH_BANKS=2; localparam int FLASH_PAGES_PER_BANK=256; localparam int FLASH_WORDS_PER_PAGE=128; Do i need to change address map for eflash or any other file from firmware perspective? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#3302 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAH2RSUPKM7XPZQ3JMXNTUTSDOAVNANCNFSM4QQJ5PDQ> .

[tjaychen]

just wanted to see if this is still an open question / issue?

[rmbhagwat]

Which all other SW parameters will get modified?

[tjaychen]

this has been updated. There are now two parameters exposed in top_earlgrey.hjson that allows flash size to be increased or decreased. Please have a look.

[rmbhagwat]

Thank you very much @tjaychen !!
This is very useful. Nice !