Messages in this thread | | | From | Jan Dąbroś <> | Date | Tue, 8 Feb 2022 15:15:24 +0100 | Subject | Re: [PATCH v3 2/2] i2c: designware: Add AMD PSP I2C bus support |
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pon., 7 lut 2022 o 12:42 Andy Shevchenko <andriy.shevchenko@linux.intel.com> napisał(a): > > On Mon, Feb 07, 2022 at 09:27:12AM +0100, Jan Dąbroś wrote: > > śr., 2 lut 2022 o 17:16 Andy Shevchenko > > <andriy.shevchenko@linux.intel.com> napisał(a): > > > On Wed, Feb 02, 2022 at 03:43:02PM +0100, Jan Dabros wrote: > > ... > > > > > +struct psp_i2c_req { > > > > + struct psp_req_buffer_hdr hdr; > > > > + enum psp_i2c_req_type type; > > > > +} __aligned(32); > > > > > > I forgot if this alignment is requirement due to DMA or so? > > > We may use ____cacheline_aligned in such case. > > > > I used some old code as a reference - this structure is mapped by PSP, > > thus alignment applied here. I'm checking this with AMD whether it is > > really needed or at least can be somehow limited - still waiting for > > their response. > > I propose to left this as is right now and eventually remove or make > > more liberal in the future. > > Would be nice to clarify sooner than later. > In either case it needs a good comment.
I confirmed that we can remove this alignment completely. Removed in v4.
Best Regards, Jan
> > ... > > > > > + return readl_poll_timeout(&mbox->cmd_fields, tmp, (tmp == expected), > > > > + 0, 1000 * PSP_CMD_TIMEOUT_MS); > > > > > > 0?! > > > > Yes, we are checking for readiness of PSP mailbox in a tight loop. We > > would like to proceed further quickly as soon as this bit is set. > > Actually checking this twice per every ACQUIRE&RELEASE - once before > > sending command (to check whether PSP is ready to accept requests) and > > second time after sending it. Do you think we should increase > > @sleep_us value? > > It depends on what you have in mind about hardware. I'm fine with either way, > but 0 has to be explained (in the comment). > > -- > With Best Regards, > Andy Shevchenko > >
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