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authorNeilBrown <neil@brown.name>2018-03-21 06:02:10 +0300
committerJames Hogan <jhogan@kernel.org>2018-03-22 03:06:30 +0300
commita63d706ea719190a79a6c769e898f70680044d3e (patch)
tree8a45b4e92f371322614cac40d06308b8c22ff8e2 /arch/mips
parent891731f6a5dbe508d12443175a7e166a2fba616a (diff)
downloadlinux-a63d706ea719190a79a6c769e898f70680044d3e.tar.xz
MIPS: ralink: Fix booting on MT7621
Since commit 3af5a67c86a3 ("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: 3af5a67c86a3 ("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>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/ralink/mt7621.c42
1 files changed, 22 insertions, 20 deletions
diff --git a/arch/mips/ralink/mt7621.c b/arch/mips/ralink/mt7621.c
index 1b274742077d..d2718de60b9b 100644
--- a/arch/mips/ralink/mt7621.c
+++ b/arch/mips/ralink/mt7621.c
@@ -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;