linux-kernel - [PATCH v2] mmc: sdhci-of-esdhc: Don't walk device-tree on every interrupt

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Message-Id: <20200903012029.25673-1-chris.packham@alliedtelesis.co.nz>
Date:   Thu,  3 Sep 2020 13:20:29 +1200
From:   Chris Packham <chris.packham@...iedtelesis.co.nz>
To:     adrian.hunter@...el.com, ulf.hansson@...aro.org, yinbo.zhu@....com
Cc:     linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Chris Packham <chris.packham@...iedtelesis.co.nz>
Subject: [PATCH v2] mmc: sdhci-of-esdhc: Don't walk device-tree on every interrupt

Commit b214fe592ab7 ("mmc: sdhci-of-esdhc: add erratum eSDHC7 support")
added code to check for a specific compatible string in the device-tree
on every esdhc interrupat. Instead of doing this record the quirk in
struct sdhci_esdhc and lookup the struct in esdhc_irq.

Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
---
I found this in passing while trying to track down another issue using ftrace.
I found it odd that I was seeing a lot of calls to __of_device_is_compatible()
coming from esdhc_irq() (the fact that this interrupt is going off on my board
is also odd, but that's a different story).

Changes in v2:
- add quirk_trans_complete_erratum to struct sdhci_esdhc so all the dt handling
  is taken care of in esdhc_init.

 drivers/mmc/host/sdhci-of-esdhc.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index 7c73d243dc6c..45881b309956 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -81,6 +81,7 @@ struct sdhci_esdhc {
 	bool quirk_tuning_erratum_type2;
 	bool quirk_ignore_data_inhibit;
 	bool quirk_delay_before_data_reset;
+	bool quirk_trans_complete_erratum;
 	bool in_sw_tuning;
 	unsigned int peripheral_clock;
 	const struct esdhc_clk_fixup *clk_fixup;
@@ -1177,10 +1178,11 @@ static void esdhc_set_uhs_signaling(struct sdhci_host *host,
 
 static u32 esdhc_irq(struct sdhci_host *host, u32 intmask)
 {
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_esdhc *esdhc = sdhci_pltfm_priv(pltfm_host);
 	u32 command;
 
-	if (of_find_compatible_node(NULL, NULL,
-				"fsl,p2020-esdhc")) {
+	if (esdhc->quirk_trans_complete_erratum) {
 		command = SDHCI_GET_CMD(sdhci_readw(host,
 					SDHCI_COMMAND));
 		if (command == MMC_WRITE_MULTIPLE_BLOCK &&
@@ -1334,8 +1336,10 @@ static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
 		esdhc->clk_fixup = match->data;
 	np = pdev->dev.of_node;
 
-	if (of_device_is_compatible(np, "fsl,p2020-esdhc"))
+	if (of_device_is_compatible(np, "fsl,p2020-esdhc")) {
 		esdhc->quirk_delay_before_data_reset = true;
+		esdhc->quirk_trans_complete_erratum = true;
+	}
 
 	clk = of_clk_get(np, 0);
 	if (!IS_ERR(clk)) {
-- 
2.28.0