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/nvmem/meson-efuse.c | 107 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 drivers/nvmem/meson-efuse.c (limited to 'drivers/nvmem/meson-efuse.c') diff --git a/drivers/nvmem/meson-efuse.c b/drivers/nvmem/meson-efuse.c new file mode 100644 index 000000000..d7f9ac99a --- /dev/null +++ b/drivers/nvmem/meson-efuse.c @@ -0,0 +1,107 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Amlogic Meson GX eFuse Driver + * + * Copyright (c) 2016 Endless Computers, Inc. + * Author: Carlo Caione + */ + +#include +#include +#include +#include +#include + +#include + +static int meson_efuse_read(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct meson_sm_firmware *fw = context; + int ret; + + ret = meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset, + bytes, 0, 0, 0); + + return ret < 0 ? ret : 0; +} + +static int meson_efuse_write(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct meson_sm_firmware *fw = context; + int ret; + + ret = meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset, + bytes, 0, 0, 0); + + return ret < 0 ? ret : 0; +} + +static const struct of_device_id meson_efuse_match[] = { + { .compatible = "amlogic,meson-gxbb-efuse", }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, meson_efuse_match); + +static int meson_efuse_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct meson_sm_firmware *fw; + struct nvmem_device *nvmem; + struct nvmem_config *econfig; + struct clk *clk; + unsigned int size; + struct device_node *sm_np __free(device_node) = + of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0); + + if (!sm_np) { + dev_err(&pdev->dev, "no secure-monitor node\n"); + return -ENODEV; + } + + fw = meson_sm_get(sm_np); + if (!fw) + return -EPROBE_DEFER; + + clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(clk)) + return dev_err_probe(dev, PTR_ERR(clk), "failed to get efuse gate"); + + if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) { + dev_err(dev, "failed to get max user"); + return -EINVAL; + } + + econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL); + if (!econfig) + return -ENOMEM; + + econfig->dev = dev; + econfig->name = dev_name(dev); + econfig->add_legacy_fixed_of_cells = true; + econfig->stride = 1; + econfig->word_size = 1; + econfig->reg_read = meson_efuse_read; + econfig->reg_write = meson_efuse_write; + econfig->size = size; + econfig->priv = fw; + + nvmem = devm_nvmem_register(&pdev->dev, econfig); + + return PTR_ERR_OR_ZERO(nvmem); +} + +static struct platform_driver meson_efuse_driver = { + .probe = meson_efuse_probe, + .driver = { + .name = "meson-efuse", + .of_match_table = meson_efuse_match, + }, +}; + +module_platform_driver(meson_efuse_driver); + +MODULE_AUTHOR("Carlo Caione "); +MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1