linux-kernel - [PATCH v2 10/12] MIPS: pm-cps: Support CM3 changes to Coherence Enable Register

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Message-ID: <1473241520-14917-11-git-send-email-matt.redfearn@imgtec.com>
Date:   Wed, 7 Sep 2016 10:45:18 +0100
From:   Matt Redfearn <matt.redfearn@...tec.com>
To:     Ralf Baechle <ralf@...ux-mips.org>
CC:     <linux-mips@...ux-mips.org>,
        Matt Redfearn <matt.redfearn@...tec.com>,
        Adam Buchbinder <adam.buchbinder@...il.com>,
        Tony Wu <tung7970@...il.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Nikolay Martynov <mar.kolya@...il.com>,
        Kees Cook <keescook@...omium.org>,
        <linux-kernel@...r.kernel.org>,
        Markos Chandras <markos.chandras@...tec.com>,
        Paul Burton <paul.burton@...tec.com>
Subject: [PATCH v2 10/12] 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@...tec.com>
Reviewed-by: Paul Burton <paul.burton@...tec.com>
---

Changes in v2: None

 arch/mips/include/asm/mips-cm.h |  1 +
 arch/mips/kernel/pm-cps.c       | 31 ++++++++++++++++++-------------
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/arch/mips/include/asm/mips-cm.h b/arch/mips/include/asm/mips-cm.h
index 58e7874e9347..ac30981a8360 100644
--- 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 440e79259566..05bcdedcf9bd 100644
--- 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);
 
-- 
2.7.4