From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- drivers/mfd/atmel-flexcom.c | 123 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 drivers/mfd/atmel-flexcom.c (limited to 'drivers/mfd/atmel-flexcom.c') diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c new file mode 100644 index 000000000..d5df5466e --- /dev/null +++ b/drivers/mfd/atmel-flexcom.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for Atmel Flexcom + * + * Copyright (C) 2015 Atmel Corporation + * + * Author: Cyrille Pitchen + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* I/O register offsets */ +#define FLEX_MR 0x0 /* Mode Register */ +#define FLEX_VERSION 0xfc /* Version Register */ + +/* Mode Register bit fields */ +#define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */ +#define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET) +#define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \ + FLEX_MR_OPMODE_MASK) + +struct atmel_flexcom { + void __iomem *base; + u32 opmode; + struct clk *clk; +}; + +static int atmel_flexcom_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct atmel_flexcom *ddata; + int err; + + ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL); + if (!ddata) + return -ENOMEM; + + platform_set_drvdata(pdev, ddata); + + err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode); + if (err) + return err; + + if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART || + ddata->opmode > ATMEL_FLEXCOM_MODE_TWI) + return -EINVAL; + + ddata->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); + if (IS_ERR(ddata->base)) + return PTR_ERR(ddata->base); + + ddata->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(ddata->clk)) + return PTR_ERR(ddata->clk); + + err = clk_prepare_enable(ddata->clk); + if (err) + return err; + + /* + * Set the Operating Mode in the Mode Register: only the selected device + * is clocked. Hence, registers of the other serial devices remain + * inaccessible and are read as zero. Also the external I/O lines of the + * Flexcom are muxed to reach the selected device. + */ + writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR); + + clk_disable_unprepare(ddata->clk); + + return devm_of_platform_populate(&pdev->dev); +} + +static const struct of_device_id atmel_flexcom_of_match[] = { + { .compatible = "atmel,sama5d2-flexcom" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); + +static int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev) +{ + struct atmel_flexcom *ddata = dev_get_drvdata(dev); + int err; + u32 val; + + err = clk_prepare_enable(ddata->clk); + if (err) + return err; + + val = FLEX_MR_OPMODE(ddata->opmode); + writel(val, ddata->base + FLEX_MR); + + clk_disable_unprepare(ddata->clk); + + return 0; +} + +static const struct dev_pm_ops __maybe_unused atmel_flexcom_pm_ops = { + .resume_noirq = atmel_flexcom_resume_noirq, +}; + +static struct platform_driver atmel_flexcom_driver = { + .probe = atmel_flexcom_probe, + .driver = { + .name = "atmel_flexcom", + .pm = pm_ptr(&atmel_flexcom_pm_ops), + .of_match_table = atmel_flexcom_of_match, + }, +}; + +module_platform_driver(atmel_flexcom_driver); + +MODULE_AUTHOR("Cyrille Pitchen "); +MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1