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400c18e3dc
The dw_mmio driver disables the block clock before unregistering the host. The code unregistering the host may access the SPI block registers. If register access happens with block clock disabled, this may lead to a bus hang. Disable the clock after unregistering the host to prevent such situation. This bug was observed on Altera Cyclone V SoC. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org>
143 lines
3.2 KiB
C
143 lines
3.2 KiB
C
/*
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* Memory-mapped interface driver for DW SPI Core
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*
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* Copyright (c) 2010, Octasic semiconductor.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*/
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/spi/spi.h>
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#include <linux/scatterlist.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <linux/of_platform.h>
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#include <linux/property.h>
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#include "spi-dw.h"
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#define DRIVER_NAME "dw_spi_mmio"
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struct dw_spi_mmio {
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struct dw_spi dws;
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struct clk *clk;
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};
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static int dw_spi_mmio_probe(struct platform_device *pdev)
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{
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struct dw_spi_mmio *dwsmmio;
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struct dw_spi *dws;
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struct resource *mem;
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int ret;
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int num_cs;
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dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
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GFP_KERNEL);
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if (!dwsmmio)
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return -ENOMEM;
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dws = &dwsmmio->dws;
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/* Get basic io resource and map it */
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mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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dws->regs = devm_ioremap_resource(&pdev->dev, mem);
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if (IS_ERR(dws->regs)) {
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dev_err(&pdev->dev, "SPI region map failed\n");
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return PTR_ERR(dws->regs);
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}
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dws->irq = platform_get_irq(pdev, 0);
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if (dws->irq < 0) {
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dev_err(&pdev->dev, "no irq resource?\n");
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return dws->irq; /* -ENXIO */
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}
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dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(dwsmmio->clk))
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return PTR_ERR(dwsmmio->clk);
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ret = clk_prepare_enable(dwsmmio->clk);
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if (ret)
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return ret;
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dws->bus_num = pdev->id;
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dws->max_freq = clk_get_rate(dwsmmio->clk);
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device_property_read_u32(&pdev->dev, "reg-io-width", &dws->reg_io_width);
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num_cs = 4;
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device_property_read_u32(&pdev->dev, "num-cs", &num_cs);
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dws->num_cs = num_cs;
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if (pdev->dev.of_node) {
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int i;
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for (i = 0; i < dws->num_cs; i++) {
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int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
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"cs-gpios", i);
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if (cs_gpio == -EPROBE_DEFER) {
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ret = cs_gpio;
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goto out;
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}
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if (gpio_is_valid(cs_gpio)) {
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ret = devm_gpio_request(&pdev->dev, cs_gpio,
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dev_name(&pdev->dev));
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if (ret)
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goto out;
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}
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}
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}
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ret = dw_spi_add_host(&pdev->dev, dws);
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if (ret)
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goto out;
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platform_set_drvdata(pdev, dwsmmio);
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return 0;
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out:
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clk_disable_unprepare(dwsmmio->clk);
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return ret;
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}
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static int dw_spi_mmio_remove(struct platform_device *pdev)
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{
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struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
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dw_spi_remove_host(&dwsmmio->dws);
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clk_disable_unprepare(dwsmmio->clk);
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return 0;
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}
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static const struct of_device_id dw_spi_mmio_of_match[] = {
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{ .compatible = "snps,dw-apb-ssi", },
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{ /* end of table */}
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};
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MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
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static struct platform_driver dw_spi_mmio_driver = {
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.probe = dw_spi_mmio_probe,
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.remove = dw_spi_mmio_remove,
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.driver = {
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.name = DRIVER_NAME,
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.of_match_table = dw_spi_mmio_of_match,
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},
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};
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module_platform_driver(dw_spi_mmio_driver);
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MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
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MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
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MODULE_LICENSE("GPL v2");
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