Re: [PATCH 2/3] EDAC, amd64_edac: Extend scrub rate programmability feature for F15hM60h

From: Aravind Gopalakrishnan
Date: Thu Sep 24 2015 - 12:15:28 EST

On 9/24/2015 4:18 AM, Borislav Petkov wrote:
On Wed, Sep 16, 2015 at 03:53:30PM -0500, Aravind Gopalakrishnan wrote:
-static int __set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
+static u32 find_scrub_rate(u32 new_bw, u32 min_rate, u32 *scrub_bw)
u32 scrubval;
int i;
@@ -200,28 +200,52 @@ static int __set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
scrubval = scrubrates[i].scrubval;
+ *scrub_bw = scrubval ? scrubrates[i].bandwidth : 0;
- pci_write_bits32(ctl, SCRCTRL, scrubval, 0x001F);
+ return scrubval;
- if (scrubval)
- return scrubrates[i].bandwidth;
+static inline void __set_scrub_rate(struct pci_dev *ctl, int offset,
+ u32 scrubval)
+ pci_write_bits32(ctl, offset, scrubval, SCRMASK);
- return 0;
What is all that churn good for?

What's wrong with simply adding the model 0x60 check to
__set_scrub_rate() and doing the proper write there?

I was thinking it's a little better from readability POV to separate out the for loop which does the job of finding the scrub value to program;
And __set_scrub_rate() writes the value to the appropriate register.

Maybe I am making it too modular?

- amd64_read_pci_cfg(pvt->F3, SCRCTRL, &scrubval);
+ if (pvt->fam == 0x15 && pvt->model == 0x60) {
+ /* Since we mirror the same scrubrate value across
+ * both DCTs, it is enough to read the value off one of
+ * the DCT registers.
+ */
+ f15h_select_dct(pvt, 0);
If it is enough, why do you select DCT 0? Just read the currently
selected one, whichever it is...

Yeah, that's a good point!
Will fix this.

static int f16_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct,
- unsigned cs_mode, int cs_mask_nr)
+ unsigned cs_mode, int cs_mask_nr)
WARN_ON(cs_mode > 12);
Why is that hunk here?

@@ -1666,7 +1699,7 @@ static int f1x_match_to_this_node(struct amd64_pvt *pvt, unsigned range,
static int f15_m30h_match_to_this_node(struct amd64_pvt *pvt, unsigned range,
- u64 sys_addr, int *chan_sel)
+ u64 sys_addr, int *chan_sel)
int cs_found = -EINVAL;
int num_dcts_intlv = 0;
That one too?

I realize it's unrelated to the patch and it's not doing something useful;
But I was thinking I'll fix the above indentation issues to keep indent rules consistent and since I was touching the file anyway.
Can remove those in a V2..

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