powerpc: Define differences between doorbells on book3e and book3s

There are a few key differences between doorbells on server compared
with embedded that we care about on Linux, namely:

- We have a new msgsndp instruction for directed privileged doorbells.
  msgsnd is used for directed hypervisor doorbells.
- The tag we use in the instruction is the Thread Identification
  Register of the recipient thread (since server doorbells can only
  occur between threads within a single core), and is only 7 bits wide.
- A new message type is introduced for server doorbells (none of the
  existing book3e message types are currently supported on book3s).

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

4 files changed, 21 insertions, 2 deletions

diff --git a/arch/powerpc/include/asm/dbell.h b/arch/powerpc/include/asm/dbell.h
index 607e4eeeb694..3b338565f992 100644
--- a/arch/powerpc/include/asm/dbell.h
+++ b/arch/powerpc/include/asm/dbell.h
@@ -28,8 +28,23 @@ enum ppc_dbell {
         PPC_G_DBELL = 2,        /* guest doorbell */
         PPC_G_DBELL_CRIT = 3,   /* guest critical doorbell */
         PPC_G_DBELL_MC = 4,     /* guest mcheck doorbell */
+        PPC_DBELL_SERVER = 5,   /* doorbell on server */
 };
 
+#ifdef CONFIG_PPC_BOOK3S
+
+#define PPC_DBELL_MSGTYPE               PPC_DBELL_SERVER
+#define SPRN_DOORBELL_CPUTAG            SPRN_TIR
+#define PPC_DBELL_TAG_MASK              0x7f
+
+#else /* CONFIG_PPC_BOOK3S */
+
+#define PPC_DBELL_MSGTYPE               PPC_DBELL
+#define SPRN_DOORBELL_CPUTAG            SPRN_PIR
+#define PPC_DBELL_TAG_MASK              0x3fff
+
+#endif /* CONFIG_PPC_BOOK3S */
+
 extern void doorbell_cause_ipi(int cpu, unsigned long data);
 extern void doorbell_exception(struct pt_regs *regs);
 extern void doorbell_setup_this_cpu(void);
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 51fb00a20d7e..0fd1928efb93 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -100,6 +100,7 @@
 #define PPC_INST_MFSPR_PVR              0x7c1f42a6
 #define PPC_INST_MFSPR_PVR_MASK         0xfc1fffff
 #define PPC_INST_MSGSND                 0x7c00019c
+#define PPC_INST_MSGSNDP                0x7c00011c
 #define PPC_INST_NOP                    0x60000000
 #define PPC_INST_POPCNTB                0x7c0000f4
 #define PPC_INST_POPCNTB_MASK           0xfc0007fe
@@ -227,6 +228,8 @@
                                         ___PPC_RB(b) | __PPC_EH(eh))
 #define PPC_MSGSND(b)           stringify_in_c(.long PPC_INST_MSGSND | \
                                         ___PPC_RB(b))
+#define PPC_MSGSNDP(b)          stringify_in_c(.long PPC_INST_MSGSNDP | \
+                                        ___PPC_RB(b))
 #define PPC_POPCNTB(a, s)       stringify_in_c(.long PPC_INST_POPCNTB | \
                                         __PPC_RA(a) | __PPC_RS(s))
 #define PPC_POPCNTD(a, s)       stringify_in_c(.long PPC_INST_POPCNTD | \
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 3d5c9dc8917a..af88486b0c23 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -483,6 +483,7 @@
 #ifndef SPRN_PIR
 #define SPRN_PIR        0x3FF   /* Processor Identification Register */
 #endif
+#define SPRN_TIR        0x1BE   /* Thread Identification Register */
 #define SPRN_PTEHI      0x3D5   /* 981 7450 PTE HI word (S/W TLB load) */
 #define SPRN_PTELO      0x3D6   /* 982 7450 PTE LO word (S/W TLB load) */
 #define SPRN_PURR       0x135   /* Processor Utilization of Resources Reg */
diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c
index a892680668d8..9ebbc24bb23c 100644
--- a/arch/powerpc/kernel/dbell.c
+++ b/arch/powerpc/kernel/dbell.c
@@ -21,7 +21,7 @@
 #ifdef CONFIG_SMP
 void doorbell_setup_this_cpu(void)
 {
-        unsigned long tag = mfspr(SPRN_PIR) & 0x3fff;
+        unsigned long tag = mfspr(SPRN_DOORBELL_CPUTAG) & PPC_DBELL_TAG_MASK;
 
         smp_muxed_ipi_set_data(smp_processor_id(), tag);
 }
@@ -30,7 +30,7 @@ void doorbell_cause_ipi(int cpu, unsigned long data)
 {
         /* Order previous accesses vs. msgsnd, which is treated as a store */
         mb();
-        ppc_msgsnd(PPC_DBELL, 0, data);
+        ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, data);
 }
 
 void doorbell_exception(struct pt_regs *regs)