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/dma/dw/of.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 drivers/dma/dw/of.c (limited to 'drivers/dma/dw/of.c') diff --git a/drivers/dma/dw/of.c b/drivers/dma/dw/of.c new file mode 100644 index 000000000..523ca8068 --- /dev/null +++ b/drivers/dma/dw/of.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Platform driver for the Synopsys DesignWare DMA Controller + * + * Copyright (C) 2007-2008 Atmel Corporation + * Copyright (C) 2010-2011 ST Microelectronics + * Copyright (C) 2013 Intel Corporation + */ + +#include +#include +#include + +#include "internal.h" + +static struct dma_chan *dw_dma_of_xlate(struct of_phandle_args *dma_spec, + struct of_dma *ofdma) +{ + struct dw_dma *dw = ofdma->of_dma_data; + struct dw_dma_slave slave = { + .dma_dev = dw->dma.dev, + }; + dma_cap_mask_t cap; + + if (dma_spec->args_count < 3 || dma_spec->args_count > 4) + return NULL; + + slave.src_id = dma_spec->args[0]; + slave.dst_id = dma_spec->args[0]; + slave.m_master = dma_spec->args[1]; + slave.p_master = dma_spec->args[2]; + if (dma_spec->args_count >= 4) + slave.channels = dma_spec->args[3]; + + if (WARN_ON(slave.src_id >= DW_DMA_MAX_NR_REQUESTS || + slave.dst_id >= DW_DMA_MAX_NR_REQUESTS || + slave.m_master >= dw->pdata->nr_masters || + slave.p_master >= dw->pdata->nr_masters || + slave.channels >= BIT(dw->pdata->nr_channels))) + return NULL; + + dma_cap_zero(cap); + dma_cap_set(DMA_SLAVE, cap); + + /* TODO: there should be a simpler way to do this */ + return dma_request_channel(cap, dw_dma_filter, &slave); +} + +struct dw_dma_platform_data *dw_dma_parse_dt(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct dw_dma_platform_data *pdata; + u32 tmp, arr[DW_DMA_MAX_NR_MASTERS]; + u32 nr_masters; + u32 nr_channels; + + if (of_property_read_u32(np, "dma-masters", &nr_masters)) + return NULL; + if (nr_masters < 1 || nr_masters > DW_DMA_MAX_NR_MASTERS) + return NULL; + + if (of_property_read_u32(np, "dma-channels", &nr_channels)) + return NULL; + if (nr_channels > DW_DMA_MAX_NR_CHANNELS) + return NULL; + + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return NULL; + + pdata->nr_masters = nr_masters; + pdata->nr_channels = nr_channels; + + of_property_read_u32(np, "chan_allocation_order", &pdata->chan_allocation_order); + of_property_read_u32(np, "chan_priority", &pdata->chan_priority); + + of_property_read_u32(np, "block_size", &pdata->block_size); + + /* Try deprecated property first */ + if (!of_property_read_u32_array(np, "data_width", arr, nr_masters)) { + for (tmp = 0; tmp < nr_masters; tmp++) + pdata->data_width[tmp] = BIT(arr[tmp] & 0x07); + } + + /* If "data_width" and "data-width" both provided use the latter one */ + of_property_read_u32_array(np, "data-width", pdata->data_width, nr_masters); + + memset32(pdata->multi_block, 1, nr_channels); + of_property_read_u32_array(np, "multi-block", pdata->multi_block, nr_channels); + + memset32(pdata->max_burst, DW_DMA_MAX_BURST, nr_channels); + of_property_read_u32_array(np, "snps,max-burst-len", pdata->max_burst, nr_channels); + + of_property_read_u32(np, "snps,dma-protection-control", &pdata->protctl); + if (pdata->protctl > CHAN_PROTCTL_MASK) + return NULL; + + return pdata; +} + +void dw_dma_of_controller_register(struct dw_dma *dw) +{ + struct device *dev = dw->dma.dev; + int ret; + + if (!dev->of_node) + return; + + ret = of_dma_controller_register(dev->of_node, dw_dma_of_xlate, dw); + if (ret) + dev_err(dev, "could not register of_dma_controller\n"); +} + +void dw_dma_of_controller_free(struct dw_dma *dw) +{ + struct device *dev = dw->dma.dev; + + if (!dev->of_node) + return; + + of_dma_controller_free(dev->of_node); +} -- cgit v1.3.1