MIPS: CM: make use of mips_cm_{lock,unlock}_other

Document that CPC core-other accesses must take place within the bounds
of the CM lock, and begin using the CM lock functions where we access
the GCRs of other cores. This is required because with CM3 the CPC began
using GCR_CL_OTHER instead of CPC_CL_OTHER.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: Niklas Cassel <niklas.cassel@axis.com>
Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11208/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mips-cpc.h

@@ -149,7 +149,8 @@ BUILD_CPC_Cx_RW(other,		0x10)
  * core: the other core to be accessed
  *
  * Call before operating upon a core via the 'other' register region in
- * order to prevent the region being moved during access. Must be followed
+ * order to prevent the region being moved during access. Must be called
+ * within the bounds of a mips_cm_{lock,unlock}_other pair, and followed
  * by a call to mips_cpc_unlock_other.
  */
 extern void mips_cpc_lock_other(unsigned int core);

arch/mips/kernel/smp-cps.c

@@ -38,8 +38,9 @@ static unsigned core_vpe_count(unsigned core)
 	if (!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
 		return 1;
 
-	write_gcr_cl_other(core << CM_GCR_Cx_OTHER_CORENUM_SHF);
+	mips_cm_lock_other(core, 0);
 	cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK;
+	mips_cm_unlock_other();
 	return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
 }
 
@@ -193,7 +194,7 @@ static void boot_core(unsigned core)
 	unsigned timeout;
 
 	/* Select the appropriate core */
-	write_gcr_cl_other(core << CM_GCR_Cx_OTHER_CORENUM_SHF);
+	mips_cm_lock_other(core, 0);
 
 	/* Set its reset vector */
 	write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));
@@ -238,6 +239,8 @@ static void boot_core(unsigned core)
 		write_gcr_co_reset_release(0);
 	}
 
+	mips_cm_unlock_other();
+
 	/* The core is now powered up */
 	bitmap_set(core_power, core, 1);
 }

arch/mips/kernel/smp-gic.c

@@ -46,9 +46,11 @@ void gic_send_ipi_single(int cpu, unsigned int action)
 
 	if (mips_cpc_present() && (core != current_cpu_data.core)) {
 		while (!cpumask_test_cpu(cpu, &cpu_coherent_mask)) {
+			mips_cm_lock_other(core, 0);
 			mips_cpc_lock_other(core);
 			write_cpc_co_cmd(CPC_Cx_CMD_PWRUP);
 			mips_cpc_unlock_other();
+			mips_cm_unlock_other();
 		}
 	}