MIPS: pm-cps: Support CM3 changes to Coherence Enable Register

MIPS CM3 changed the management of coherence. Instead of a coherence
control register with a bitmask of coherent domains, CM3 simply has a
coherence enable register with a single bit to enable coherence of the
local core. Support this by clearing and setting this single bit to
disable / enable coherence.

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Tony Wu <tung7970@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nikolay Martynov <mar.kolya@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14226/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/include/asm/mips-cm.h b/arch/mips/include/asm/mips-cm.h
index 4fafeef..2e41807 100644 (file)
--- a/arch/mips/include/asm/mips-cm.h
+++ b/arch/mips/include/asm/mips-cm.h
@@ -359,6 +359,7 @@ BUILD_CM_Cx_R_(tcid_8_priority,     0x80)
 /* GCR_Cx_COHERENCE register fields */
 #define CM_GCR_Cx_COHERENCE_COHDOMAINEN_SHF    0
 #define CM_GCR_Cx_COHERENCE_COHDOMAINEN_MSK    (_ULCAST_(0xff) << 0)
+#define CM3_GCR_Cx_COHERENCE_COHEN_MSK         (_ULCAST_(0x1) << 0)
 
 /* GCR_Cx_CONFIG register fields */
 #define CM_GCR_Cx_CONFIG_IOCUTYPE_SHF          10

diff --git a/arch/mips/kernel/pm-cps.c b/arch/mips/kernel/pm-cps.c
index 440e792..05bcded 100644 (file)
--- a/arch/mips/kernel/pm-cps.c
+++ b/arch/mips/kernel/pm-cps.c
@@ -480,18 +480,20 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum cps_pm_state state)
        uasm_i_sync(&p, STYPE_SYNC);
        uasm_i_ehb(&p);
 
-       /*
-        * Disable all but self interventions. The load from COHCTL is defined
-        * by the interAptiv & proAptiv SUMs as ensuring that the operation
-        * resulting from the preceding store is complete.
-        */
-       uasm_i_addiu(&p, t0, zero, 1 << cpu_data[cpu].core);
-       uasm_i_sw(&p, t0, 0, r_pcohctl);
-       uasm_i_lw(&p, t0, 0, r_pcohctl);
-
-       /* Barrier to ensure write to coherence control is complete */
-       uasm_i_sync(&p, STYPE_SYNC);
-       uasm_i_ehb(&p);
+       if (mips_cm_revision() < CM_REV_CM3) {
+               /*
+               * Disable all but self interventions. The load from COHCTL is
+               * defined by the interAptiv & proAptiv SUMs as ensuring that the
+               *  operation resulting from the preceding store is complete.
+               */
+               uasm_i_addiu(&p, t0, zero, 1 << cpu_data[cpu].core);
+               uasm_i_sw(&p, t0, 0, r_pcohctl);
+               uasm_i_lw(&p, t0, 0, r_pcohctl);
+
+               /* Barrier to ensure write to coherence control is complete */
+               uasm_i_sync(&p, STYPE_SYNC);
+               uasm_i_ehb(&p);
+       }
 
        /* Disable coherence */
        uasm_i_sw(&p, zero, 0, r_pcohctl);
@@ -566,7 +568,10 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum cps_pm_state state)
         * will run this. The first will actually re-enable coherence & the
         * rest will just be performing a rather unusual nop.
         */
-       uasm_i_addiu(&p, t0, zero, CM_GCR_Cx_COHERENCE_COHDOMAINEN_MSK);
+       uasm_i_addiu(&p, t0, zero, mips_cm_revision() < CM_REV_CM3
+                               ? CM_GCR_Cx_COHERENCE_COHDOMAINEN_MSK
+                               : CM3_GCR_Cx_COHERENCE_COHEN_MSK);
+
        uasm_i_sw(&p, t0, 0, r_pcohctl);
        uasm_i_lw(&p, t0, 0, r_pcohctl);