MIPS: BMIPS: Introduce helper function to change the reset vector

This will need to be called from a few different places, and the logic
is starting to get a bit hairy (with the need for IPIs, CPU bug
workarounds, and hazards).

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8158/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 58 insertions, 7 deletions

diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
index 4e569113ff56..8383fa460d42 100644
--- a/arch/mips/kernel/smp-bmips.c
+++ b/arch/mips/kernel/smp-bmips.c
@@ -35,6 +35,7 @@
 #include <asm/bmips.h>
 #include <asm/traps.h>
 #include <asm/barrier.h>
+#include <asm/cpu-features.h>
 
 static int __maybe_unused max_cpus = 1;
 
@@ -43,6 +44,9 @@ int bmips_smp_enabled = 1;
 int bmips_cpu_offset;
 cpumask_t bmips_booted_mask;
 
+#define RESET_FROM_KSEG0                0x80080800
+#define RESET_FROM_KSEG1                0xa0080800
+
 #ifdef CONFIG_SMP
 
 /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
@@ -463,10 +467,61 @@ static inline void bmips_nmi_handler_setup(void)
                 &bmips_smp_int_vec_end);
 }
 
+struct reset_vec_info {
+        int cpu;
+        u32 val;
+};
+
+static void bmips_set_reset_vec_remote(void *vinfo)
+{
+        struct reset_vec_info *info = vinfo;
+        int shift = info->cpu & 0x01 ? 16 : 0;
+        u32 mask = ~(0xffff << shift), val = info->val >> 16;
+
+        preempt_disable();
+        if (smp_processor_id() > 0) {
+                smp_call_function_single(0, &bmips_set_reset_vec_remote,
+                                         info, 1);
+        } else {
+                if (info->cpu & 0x02) {
+                        /* BMIPS5200 "should" use mask/shift, but it's buggy */
+                        bmips_write_zscm_reg(0xa0, (val << 16) | val);
+                        bmips_read_zscm_reg(0xa0);
+                } else {
+                        write_c0_brcm_bootvec((read_c0_brcm_bootvec() & mask) |
+                                              (val << shift));
+                }
+        }
+        preempt_enable();
+}
+
+static void bmips_set_reset_vec(int cpu, u32 val)
+{
+        struct reset_vec_info info;
+
+        if (current_cpu_type() == CPU_BMIPS5000) {
+                /* this needs to run from CPU0 (which is always online) */
+                info.cpu = cpu;
+                info.val = val;
+                bmips_set_reset_vec_remote(&info);
+        } else {
+                void __iomem *cbr = BMIPS_GET_CBR();
+
+                if (cpu == 0)
+                        __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
+                else {
+                        if (current_cpu_type() != CPU_BMIPS4380)
+                                return;
+                        __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
+                }
+        }
+        __sync();
+        back_to_back_c0_hazard();
+}
+
 void bmips_ebase_setup(void)
 {
         unsigned long new_ebase = ebase;
-        void __iomem __maybe_unused *cbr;
 
         BUG_ON(ebase != CKSEG0);
 
@@ -492,9 +547,7 @@ void bmips_ebase_setup(void)
                  * 0x8000_0400: normal vectors
                  */
                 new_ebase = 0x80000400;
-                cbr = BMIPS_GET_CBR();
-                __raw_writel(0x80080800, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
-                __raw_writel(0xa0080800, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
+                bmips_set_reset_vec(0, RESET_FROM_KSEG0);
                 break;
         case CPU_BMIPS5000:
                 /*
@@ -502,10 +555,8 @@ void bmips_ebase_setup(void)
                  * 0x8000_1000: normal vectors
                  */
                 new_ebase = 0x80001000;
-                write_c0_brcm_bootvec(0xa0088008);
+                bmips_set_reset_vec(0, RESET_FROM_KSEG0);
                 write_c0_ebase(new_ebase);
-                if (max_cpus > 2)
-                        bmips_write_zscm_reg(0xa0, 0xa008a008);
                 break;
         default:
                 return;