linux-kernel - [PATCH v4 07/47] soc: fsl: qe: qe.c: guard use of pvr_version_is() with CONFIG

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Message-Id: <20191108130123.6839-8-linux@rasmusvillemoes.dk>
Date:   Fri,  8 Nov 2019 14:00:43 +0100
From:   Rasmus Villemoes <linux@...musvillemoes.dk>
To:     Qiang Zhao <qiang.zhao@....com>, Li Yang <leoyang.li@....com>,
        Christophe Leroy <christophe.leroy@....fr>
Cc:     linuxppc-dev@...ts.ozlabs.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Scott Wood <oss@...error.net>,
        Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [PATCH v4 07/47] soc: fsl: qe: qe.c: guard use of pvr_version_is() with CONFIG_PPC32

Commit e5c5c8d23fef (soc/fsl/qe: only apply QE_General4 workaround on
affected SoCs) introduced use of pvr_version_is(), saying

    The QE_General4 workaround is only valid for the MPC832x and MPC836x
    SoCs. The other SoCs that embed a QUICC engine are not affected by this
    hardware bug and thus can use the computed divisors (this was
    successfully tested on the T1040).

I'm reading the above as saying that the errata does not apply to the
ARM-based SOCs with QUICC engine. In any case, use of pvr_version_is()
must be guarded by CONFIG_PPC32 before we can remove the PPC32
dependency from CONFIG_QUICC_ENGINE, so introduce qe_general4_errata()
to keep the necessary #ifdeffery localized to a trivial helper.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
 drivers/soc/fsl/qe/qe.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/fsl/qe/qe.c b/drivers/soc/fsl/qe/qe.c
index 85737e6f5b62..1d8aa62c7ddf 100644
--- a/drivers/soc/fsl/qe/qe.c
+++ b/drivers/soc/fsl/qe/qe.c
@@ -197,6 +197,14 @@ EXPORT_SYMBOL(qe_get_brg_clk);
 #define PVR_VER_836x	0x8083
 #define PVR_VER_832x	0x8084
 
+static bool qe_general4_errata(void)
+{
+#ifdef CONFIG_PPC32
+	return pvr_version_is(PVR_VER_836x) || pvr_version_is(PVR_VER_832x);
+#endif
+	return false;
+}
+
 /* Program the BRG to the given sampling rate and multiplier
  *
  * @brg: the BRG, QE_BRG1 - QE_BRG16
@@ -223,7 +231,7 @@ int qe_setbrg(enum qe_clock brg, unsigned int rate, unsigned int multiplier)
 	/* Errata QE_General4, which affects some MPC832x and MPC836x SOCs, says
 	   that the BRG divisor must be even if you're not using divide-by-16
 	   mode. */
-	if (pvr_version_is(PVR_VER_836x) || pvr_version_is(PVR_VER_832x))
+	if (qe_general4_errata())
 		if (!div16 && (divisor & 1) && (divisor > 3))
 			divisor++;
 
-- 
2.23.0