[lkml]   [2020]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 05/16] bus: mhi: core: Add support for ringing channel/event ring doorbells
On Thu, Jan 23, 2020 at 12:19 PM Manivannan Sadhasivam
<> wrote:

> +int __must_check mhi_read_reg(struct mhi_controller *mhi_cntrl,
> + void __iomem *base, u32 offset, u32 *out)
> +{
> + u32 tmp = readl_relaxed(base + offset);
> +void mhi_write_reg(struct mhi_controller *mhi_cntrl, void __iomem *base,
> + u32 offset, u32 val)
> +{
> + writel_relaxed(val, base + offset);

Please avoid using _relaxed accessors by default, and use the regular
ones instead. There are a number of things that can go wrong with
the relaxed version, so ideally each caller should have a comment
explaining why this instance is safe without the barriers and why it
matters to not have it.

If there are performance critical callers of mhi_read_reg/mhi_write_reg,
you could add mhi_read_reg_relaxed/mhi_write_reg_relaxed for those
and apply the same rules there.

Usually most mmio accesses are only needed for reconfiguration or
other slow paths.


 \ /
  Last update: 2020-01-23 12:39    [W:0.263 / U:37.940 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site