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powerpc: Add an inline function to update POWER8 HID0 

Section 3.7 of Version 1.2 of the Power8 Processor User's Manual
prescribes that updates to HID0 be preceded by a SYNC instruction and
followed by an ISYNC instruction (Page 91).

Create an inline function name update_power8_hid0() which follows this
recipe and invoke it from the static split core path.

Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Tested-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Gautham R. Shenoy 2015-08-05 12:38:31 +05:30 committed by Michael Ellerman
parent 9afac93343
commit e63dbd16ab
2 changed files with 11 additions and 2 deletions
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9
arch/powerpc/include/asm/reg.h
View File

@ -1280,6 +1280,15 @@ struct pt_regs;
extern void ppc_save_regs(struct pt_regs *regs);
static inline void update_power8_hid0(unsigned long hid0)
{
/*
* The HID0 update on Power8 should at the very least be
* preceded by a a SYNC instruction followed by an ISYNC
* instruction
*/
asm volatile("sync; mtspr %0,%1; isync":: "i"(SPRN_HID0), "r"(hid0));
}
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_REG_H */

4
arch/powerpc/platforms/powernv/subcore.c
View File

@ -190,7 +190,7 @@ static void unsplit_core(void)
hid0 = mfspr(SPRN_HID0);
hid0 &= ~HID0_POWER8_DYNLPARDIS;
mtspr(SPRN_HID0, hid0);
update_power8_hid0(hid0);
update_hid_in_slw(hid0);
while (mfspr(SPRN_HID0) & mask)
@ -227,7 +227,7 @@ static void split_core(int new_mode)
/* Write new mode */
hid0 = mfspr(SPRN_HID0);
hid0 |= HID0_POWER8_DYNLPARDIS | split_parms[i].value;
mtspr(SPRN_HID0, hid0);
update_power8_hid0(hid0);
update_hid_in_slw(hid0);
/* Wait for it to happen */