Export symbols / Allow calls from other modules

[kevin-servaenergy]

Hi. This PR is to export symbols for use in other kernel modules as a softdep. For background, I needed to write a custom module to facilitate dma transfers for a FPGA.

I only exported the symbols that were required for my module.

• Creating and deleting dma buffers as needed
• Retrieving the size of a dma buffer
• Retrieving the 'phys_addr' property

[ikwzm]

Thank you for your pull request. Please give me a little more time.

[ikwzm]

Inspired by your PR, I created a draft version that exports some functions to u-dma-buf for in-kernel. It is located in the branch shown below.

https://github.com/ikwzm/udmabuf/tree/in-kernel-develop

I made the following changes to u-dma-buf.c:

• [add] the following functions for use from in-kernel modules.
  • u_dma_buf_device_search() - Search u-dma-buf device by name or id.
  • u_dma_buf_device_create() - Create u-dma-buf device for in-kernel.
  • u_dma_buf_device_remove() - Remove u-dma-buf device for in-kernel.
  • u_dma_buf_device_getmap() - Get mapping information from u-dma-buf device for in-kernel.
  • u_dma_buf_device_sync() - Sync for CPU/Device u-dma-buf device for in-kernel.
    • [remove] u-dma-buf-mgr from u-dma-buf.c, because u-dma-buf-gmr is migrated to another kernel module.

[kevin-servaenergy]

Awesome! Looks good. Tried out your branch and everything seems to work.

[ikwzm]

Thanks for trying. I'll test it for a while and then release it.

[ikwzm]

Thank you for your pull request. I will close this pull request with thanks to you.