cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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omap-ocp2scp.c (3135B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * omap-ocp2scp.c - transform ocp interface protocol to scp protocol
      4 *
      5 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
      6 * Author: Kishon Vijay Abraham I <kishon@ti.com>
      7 */
      8
      9#include <linux/io.h>
     10#include <linux/module.h>
     11#include <linux/platform_device.h>
     12#include <linux/err.h>
     13#include <linux/pm_runtime.h>
     14#include <linux/of.h>
     15#include <linux/of_platform.h>
     16
     17#define OCP2SCP_TIMING 0x18
     18#define SYNC2_MASK 0xf
     19
     20static int ocp2scp_remove_devices(struct device *dev, void *c)
     21{
     22	struct platform_device *pdev = to_platform_device(dev);
     23
     24	platform_device_unregister(pdev);
     25
     26	return 0;
     27}
     28
     29static int omap_ocp2scp_probe(struct platform_device *pdev)
     30{
     31	int ret;
     32	u32 reg;
     33	void __iomem *regs;
     34	struct resource *res;
     35	struct device_node *np = pdev->dev.of_node;
     36
     37	if (np) {
     38		ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
     39		if (ret) {
     40			dev_err(&pdev->dev,
     41			    "failed to add resources for ocp2scp child\n");
     42			goto err0;
     43		}
     44	}
     45
     46	pm_runtime_enable(&pdev->dev);
     47	/*
     48	 * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
     49	 * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
     50	 * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
     51	 * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
     52	 * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
     53	 * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
     54	 * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
     55	 * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
     56	 *
     57	 * Read path of OCP2SCP is not working properly due to low reset value
     58	 * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
     59	 */
     60	if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
     61		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
     62		regs = devm_ioremap_resource(&pdev->dev, res);
     63		if (IS_ERR(regs)) {
     64			ret = PTR_ERR(regs);
     65			goto err1;
     66		}
     67
     68		pm_runtime_get_sync(&pdev->dev);
     69		reg = readl_relaxed(regs + OCP2SCP_TIMING);
     70		reg &= ~(SYNC2_MASK);
     71		reg |= 0x6;
     72		writel_relaxed(reg, regs + OCP2SCP_TIMING);
     73		pm_runtime_put_sync(&pdev->dev);
     74	}
     75
     76	return 0;
     77
     78err1:
     79	pm_runtime_disable(&pdev->dev);
     80
     81err0:
     82	device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
     83
     84	return ret;
     85}
     86
     87static int omap_ocp2scp_remove(struct platform_device *pdev)
     88{
     89	pm_runtime_disable(&pdev->dev);
     90	device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
     91
     92	return 0;
     93}
     94
     95#ifdef CONFIG_OF
     96static const struct of_device_id omap_ocp2scp_id_table[] = {
     97	{ .compatible = "ti,omap-ocp2scp" },
     98	{ .compatible = "ti,am437x-ocp2scp" },
     99	{}
    100};
    101MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
    102#endif
    103
    104static struct platform_driver omap_ocp2scp_driver = {
    105	.probe		= omap_ocp2scp_probe,
    106	.remove		= omap_ocp2scp_remove,
    107	.driver		= {
    108		.name	= "omap-ocp2scp",
    109		.of_match_table = of_match_ptr(omap_ocp2scp_id_table),
    110	},
    111};
    112
    113module_platform_driver(omap_ocp2scp_driver);
    114
    115MODULE_ALIAS("platform:omap-ocp2scp");
    116MODULE_AUTHOR("Texas Instruments Inc.");
    117MODULE_DESCRIPTION("OMAP OCP2SCP driver");
    118MODULE_LICENSE("GPL v2");