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MIPS: ralink: Fix booting on MT7621

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Since commit 3af5a67c86 ("MIPS: Fix early CM probing") the MT7621 has
not been able to boot.

This commit caused mips_cm_probe() to be called before
mt7621.c::proc_soc_init().

prom_soc_init() has a comment explaining that mips_cm_probe() "wipes out
the bootloader config" and means that configuration registers are no
longer available. It has some code to re-enable this config.

Before this re-enable code is run, the sysc register cannot be read, so
when SYSC_REG_CHIP_NAME0 is read, a garbage value is returned and
panic() is called.

If we move the config-repair code to the top of prom_soc_init(), the
registers can be read and boot can proceed.

Very occasionally, the first register read after the reconfiguration
returns garbage, so add a call to __sync().

Fixes: 3af5a67c86 ("MIPS: Fix early CM probing")
Signed-off-by: NeilBrown <neil@brown.name>
Reviewed-by: Matt Redfearn <matt.redfearn@mips.com>
Cc: John Crispin <john@phrozen.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.5+
Patchwork: https://patchwork.linux-mips.org/patch/18859/
Signed-off-by: James Hogan <jhogan@kernel.org>
This commit is contained in:
NeilBrown 2018-03-21 14:02:10 +11:00 committed by James Hogan
parent 891731f6a5
commit a63d706ea7
No known key found for this signature in database
GPG key ID: 6C0B6993DE38767A
1 changed files with 22 additions and 20 deletions
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42
arch/mips/ralink/mt7621.c
View file

@ -170,6 +170,28 @@ void prom_soc_init(struct ralink_soc_info *soc_info)
u32 n1;
u32 rev;
/* Early detection of CMP support */
mips_cm_probe();
mips_cpc_probe();
if (mips_cps_numiocu(0)) {
/*
* mips_cm_probe() wipes out bootloader
* config for CM regions and we have to configure them
* again. This SoC cannot talk to pamlbus devices
* witout proper iocu region set up.
*
* FIXME: it would be better to do this with values
* from DT, but we need this very early because
* without this we cannot talk to pretty much anything
* including serial.
*/
write_gcr_reg0_base(MT7621_PALMBUS_BASE);
write_gcr_reg0_mask(~MT7621_PALMBUS_SIZE |
CM_GCR_REGn_MASK_CMTGT_IOCU0);
__sync();
}
n0 = __raw_readl(sysc + SYSC_REG_CHIP_NAME0);
n1 = __raw_readl(sysc + SYSC_REG_CHIP_NAME1);
@ -194,26 +216,6 @@ void prom_soc_init(struct ralink_soc_info *soc_info)
rt2880_pinmux_data = mt7621_pinmux_data;
/* Early detection of CMP support */
mips_cm_probe();
mips_cpc_probe();
if (mips_cps_numiocu(0)) {
/*
* mips_cm_probe() wipes out bootloader
* config for CM regions and we have to configure them
* again. This SoC cannot talk to pamlbus devices
* witout proper iocu region set up.
*
* FIXME: it would be better to do this with values
* from DT, but we need this very early because
* without this we cannot talk to pretty much anything
* including serial.
*/
write_gcr_reg0_base(MT7621_PALMBUS_BASE);
write_gcr_reg0_mask(~MT7621_PALMBUS_SIZE |
CM_GCR_REGn_MASK_CMTGT_IOCU0);
}
if (!register_cps_smp_ops())
return;