From: Michael Ellerman <mpe@ellerman.id.au>
To: <linuxppc-dev@lists.ozlabs.org>
Cc: bhelgaas@google.com, nathan@kernel.org, ndesaulniers@google.com
Subject: [PATCH] powerpc/32: Drop unused grackle_set_stg()
Date: Mon, 13 Nov 2023 16:19:29 +1100 [thread overview]
Message-ID: <20231113051929.1952351-1-mpe@ellerman.id.au> (raw)
The call to grackle_set_stg() ("Store Gathering") has always been inside
an #ifdef 0, since the code was first merged in v2.3.43pre7.
Apparently it was suspected of causing problems on some hardware so was
disabled. No one has ever proved otherwise so drop the code as unused
for now.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Bjorn Helgaas <helgaas@kernel.org>
Closes: https://lore.kernel.org/all/20231031145600.GA9161@bhelgaas/
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/sysdev/grackle.c | 19 -------------------
1 file changed, 19 deletions(-)
Some additional detail too verbose/boring for the change log.
Initial commit introducing the code, under #ifdef 0:
https://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux-fullhistory.git/tree/arch/ppc/kernel/pmac_pci.c?id=2fac5cbf1dd9a7720aa0130575a0b36ba4f04ede#n623
Discussion of the hardware problems it might have caused, but with no meaningful conclusion:
https://lore.kernel.org/all/20000903134303.2744@192.168.1.10/
diff --git a/arch/powerpc/sysdev/grackle.c b/arch/powerpc/sysdev/grackle.c
index fd2f94a884f0..7dce8278b71e 100644
--- a/arch/powerpc/sysdev/grackle.c
+++ b/arch/powerpc/sysdev/grackle.c
@@ -18,24 +18,8 @@
#define GRACKLE_CFA(b, d, o) (0x80 | ((b) << 8) | ((d) << 16) \
| (((o) & ~3) << 24))
-#define GRACKLE_PICR1_STG 0x00000040
#define GRACKLE_PICR1_LOOPSNOOP 0x00000010
-/* N.B. this is called before bridges is initialized, so we can't
- use grackle_pcibios_{read,write}_config_dword. */
-static inline void grackle_set_stg(struct pci_controller* bp, int enable)
-{
- unsigned int val;
-
- out_be32(bp->cfg_addr, GRACKLE_CFA(0, 0, 0xa8));
- val = in_le32(bp->cfg_data);
- val = enable? (val | GRACKLE_PICR1_STG) :
- (val & ~GRACKLE_PICR1_STG);
- out_be32(bp->cfg_addr, GRACKLE_CFA(0, 0, 0xa8));
- out_le32(bp->cfg_data, val);
- (void)in_le32(bp->cfg_data);
-}
-
static inline void grackle_set_loop_snoop(struct pci_controller *bp, int enable)
{
unsigned int val;
@@ -56,7 +40,4 @@ void __init setup_grackle(struct pci_controller *hose)
pci_add_flags(PCI_REASSIGN_ALL_BUS);
if (of_machine_is_compatible("AAPL,PowerBook1998"))
grackle_set_loop_snoop(hose, 1);
-#if 0 /* Disabled for now, HW problems ??? */
- grackle_set_stg(hose, 1);
-#endif
}
--
2.41.0
next reply other threads:[~2023-11-13 5:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-13 5:19 Michael Ellerman [this message]
2023-12-07 12:38 ` [PATCH] powerpc/32: Drop unused grackle_set_stg() Michael Ellerman
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