[PATCH 1/3] ARM: MM: Add the workaround of Errata 774769

Russell King - ARM Linux wrote:

quoted

-3:	mov	r10, #0
+	/* Cortex-A15 Errata */
+3:	ldr	r10, =0x00000c0f		@ Cortex-A15 primary part number
+	teq	r0, r10
+	bne	4f
+#ifdef CONFIG_ARM_ERRATA_774769

There's not much point testing for the part number of the work-around isn't
enabled.

The errata 773022 on second patch series is also required to checking the part number.
In my opinion, the testing for Cortex-A15 primary part number is required
before working the work-around to support several A15 errata.

quoted

+	teq	r6, #0x4			@ present in r0p4
+	mrceq	p15, 0, r10, c1, c0, 1		@ read aux control register

	tsteq	r10, #1 << 15

to avoid writing to the aux control register if the errata has already been
applied.

Do you mean "tsteq	r10, #1 << 25" ?
If yes, it needs to branch and will make a little complicated
And, I think maybe this function could be the first step to configure this erratum.

Thanks for your review

quoted

+	orreq	r10, r10, #1 << 25		@ set bit #25
+	mcreq	p15, 0, r10, c1, c0, 1		@ write aux control register
+#endif
+
+4:	mov	r10, #0
 	mcr	p15, 0, r10, c7, c5, 0		@ I+BTB cache invalidate
 	dsb
 #ifdef CONFIG_MMU
--
1.7.5.4

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