linux-kernel - [PATCH v3 02/16] ipmi: kcs_bmc: Make status update atomic

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Message-Id: <20210510054213.1610760-3-andrew@aj.id.au>
Date:   Mon, 10 May 2021 15:11:59 +0930
From:   Andrew Jeffery <andrew@...id.au>
To:     openipmi-developer@...ts.sourceforge.net, openbmc@...ts.ozlabs.org,
        minyard@....org
Cc:     devicetree@...r.kernel.org, tmaimon77@...il.com,
        linux-aspeed@...ts.ozlabs.org, avifishman70@...il.com,
        venture@...gle.com, linux-kernel@...r.kernel.org,
        tali.perry1@...il.com, robh+dt@...nel.org,
        chiawei_wang@...eedtech.com, linux-arm-kernel@...ts.infradead.org,
        benjaminfair@...gle.com, arnd@...db.de, zweiss@...inix.com
Subject: [PATCH v3 02/16] ipmi: kcs_bmc: Make status update atomic

Enable more efficient implementation of read-modify-write sequences.
Both device drivers for the KCS BMC stack use regmaps. The new callback
allows us to exploit regmap_update_bits().

Signed-off-by: Andrew Jeffery <andrew@...id.au>
Reviewed-by: Zev Weiss <zweiss@...inix.com>
---
 drivers/char/ipmi/kcs_bmc.c         |  7 +------
 drivers/char/ipmi/kcs_bmc.h         |  1 +
 drivers/char/ipmi/kcs_bmc_aspeed.c  |  9 +++++++++
 drivers/char/ipmi/kcs_bmc_npcm7xx.c | 10 ++++++++++
 4 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
index f292e74bd4a5..58fb1a7bd50d 100644
--- a/drivers/char/ipmi/kcs_bmc.c
+++ b/drivers/char/ipmi/kcs_bmc.c
@@ -67,12 +67,7 @@ static inline void write_status(struct kcs_bmc *kcs_bmc, u8 data)
 
 static void update_status_bits(struct kcs_bmc *kcs_bmc, u8 mask, u8 val)
 {
-	u8 tmp = read_status(kcs_bmc);
-
-	tmp &= ~mask;
-	tmp |= val & mask;
-
-	write_status(kcs_bmc, tmp);
+	kcs_bmc->io_updateb(kcs_bmc, kcs_bmc->ioreg.str, mask, val);
 }
 
 static inline void set_state(struct kcs_bmc *kcs_bmc, u8 state)
diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
index eb9ea4ce78b8..970f53892f2d 100644
--- a/drivers/char/ipmi/kcs_bmc.h
+++ b/drivers/char/ipmi/kcs_bmc.h
@@ -76,6 +76,7 @@ struct kcs_bmc {
 	struct kcs_ioreg ioreg;
 	u8 (*io_inputb)(struct kcs_bmc *kcs_bmc, u32 reg);
 	void (*io_outputb)(struct kcs_bmc *kcs_bmc, u32 reg, u8 b);
+	void (*io_updateb)(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 val);
 
 	enum kcs_phases phase;
 	enum kcs_errors error;
diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
index c94d36e195be..06628ca69750 100644
--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
@@ -90,6 +90,14 @@ static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
 	WARN(rc != 0, "regmap_write() failed: %d\n", rc);
 }
 
+static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 val)
+{
+	struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
+	int rc;
+
+	rc = regmap_update_bits(priv->map, reg, mask, val);
+	WARN(rc != 0, "regmap_update_bits() failed: %d\n", rc);
+}
 
 /*
  * AST_usrGuide_KCS.pdf
@@ -343,6 +351,7 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
 	kcs_bmc->ioreg = ast_kcs_bmc_ioregs[channel - 1];
 	kcs_bmc->io_inputb = aspeed_kcs_inb;
 	kcs_bmc->io_outputb = aspeed_kcs_outb;
+	kcs_bmc->io_updateb = aspeed_kcs_updateb;
 
 	addr = ops->get_io_address(pdev);
 	if (addr < 0)
diff --git a/drivers/char/ipmi/kcs_bmc_npcm7xx.c b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
index 722f7391fe1f..1f44aadec9e8 100644
--- a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
+++ b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
@@ -97,6 +97,15 @@ static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
 	WARN(rc != 0, "regmap_write() failed: %d\n", rc);
 }
 
+static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 data)
+{
+	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
+	int rc;
+
+	rc = regmap_update_bits(priv->map, reg, mask, data);
+	WARN(rc != 0, "regmap_update_bits() failed: %d\n", rc);
+}
+
 static void npcm7xx_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
 {
 	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
@@ -163,6 +172,7 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
 	kcs_bmc->ioreg.str = priv->reg->sts;
 	kcs_bmc->io_inputb = npcm7xx_kcs_inb;
 	kcs_bmc->io_outputb = npcm7xx_kcs_outb;
+	kcs_bmc->io_updateb = npcm7xx_kcs_updateb;
 
 	dev_set_drvdata(dev, kcs_bmc);
 
-- 
2.27.0