linux-kernel - [PATCH 1/3] memory: brcmstb_memc: Cache configuration register value

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Message-Id: <20230324165231.3468069-2-f.fainelli@gmail.com>
Date:   Fri, 24 Mar 2023 09:52:29 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@...adcom.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        linux-arm-kernel@...ts.infradead.org (moderated list:BROADCOM BCM7XXX
        ARM ARCHITECTURE)
Subject: [PATCH 1/3] memory: brcmstb_memc: Cache configuration register value

The configuration register does not change once the DDR controller is
configured, in preparation for providing more information about the DDR
type/width in subsequent changes, store this value so we can retrieve
it.

Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
 drivers/memory/brcmstb_memc.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/memory/brcmstb_memc.c b/drivers/memory/brcmstb_memc.c
index 233a53f5bce1..67c75e21c95e 100644
--- a/drivers/memory/brcmstb_memc.c
+++ b/drivers/memory/brcmstb_memc.c
@@ -29,18 +29,15 @@ struct brcmstb_memc {
 	struct device *dev;
 	void __iomem *ddr_ctrl;
 	unsigned int timeout_cycles;
+	u32 config_reg;
 	u32 frequency;
 	u32 srpd_offset;
 };
 
 static int brcmstb_memc_uses_lpddr4(struct brcmstb_memc *memc)
 {
-	void __iomem *config = memc->ddr_ctrl + REG_MEMC_CNTRLR_CONFIG;
-	u32 reg;
-
-	reg = readl_relaxed(config) & CNTRLR_CONFIG_MASK;
-
-	return reg == CNTRLR_CONFIG_LPDDR4_SHIFT;
+	return (memc->config_reg & CNTRLR_CONFIG_MASK) ==
+		CNTRLR_CONFIG_LPDDR4_SHIFT;
 }
 
 static int brcmstb_memc_srpd_config(struct brcmstb_memc *memc,
@@ -148,6 +145,9 @@ static int brcmstb_memc_probe(struct platform_device *pdev)
 	of_property_read_u32(pdev->dev.of_node, "clock-frequency",
 			     &memc->frequency);
 
+	memc->config_reg = readl_relaxed(memc->ddr_ctrl +
+					 REG_MEMC_CNTRLR_CONFIG);
+
 	ret = sysfs_create_group(&dev->kobj, &dev_attr_group);
 	if (ret)
 		return ret;
-- 
2.34.1