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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hdq1w.c (1773B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * IP block integration code for the HDQ1W/1-wire IP block
      4 *
      5 * Copyright (C) 2012 Texas Instruments, Inc.
      6 * Paul Walmsley
      7 *
      8 * Based on the I2C reset code in arch/arm/mach-omap2/i2c.c by
      9 *     Avinash.H.M <avinashhm@ti.com>
     10 */
     11
     12#include <linux/kernel.h>
     13#include <linux/init.h>
     14#include <linux/err.h>
     15#include <linux/platform_device.h>
     16
     17#include "soc.h"
     18#include "omap_hwmod.h"
     19#include "omap_device.h"
     20#include "hdq1w.h"
     21
     22#include "prm.h"
     23#include "common.h"
     24
     25/**
     26 * omap_hdq1w_reset - reset the OMAP HDQ1W module
     27 * @oh: struct omap_hwmod *
     28 *
     29 * OCP soft reset the HDQ1W IP block.  Section 20.6.1.4 "HDQ1W/1-Wire
     30 * Software Reset" of the OMAP34xx Technical Reference Manual Revision
     31 * ZR (SWPU223R) does not include the rather important fact that, for
     32 * the reset to succeed, the HDQ1W module's internal clock gate must be
     33 * programmed to allow the clock to propagate to the rest of the
     34 * module.  In this sense, it's rather similar to the I2C custom reset
     35 * function.  Returns 0.
     36 */
     37int omap_hdq1w_reset(struct omap_hwmod *oh)
     38{
     39	u32 v;
     40	int c = 0;
     41
     42	/* Write to the SOFTRESET bit */
     43	omap_hwmod_softreset(oh);
     44
     45	/* Enable the module's internal clocks */
     46	v = omap_hwmod_read(oh, HDQ_CTRL_STATUS_OFFSET);
     47	v |= 1 << HDQ_CTRL_STATUS_CLOCKENABLE_SHIFT;
     48	omap_hwmod_write(v, oh, HDQ_CTRL_STATUS_OFFSET);
     49
     50	/* Poll on RESETDONE bit */
     51	omap_test_timeout((omap_hwmod_read(oh,
     52					   oh->class->sysc->syss_offs)
     53			   & SYSS_RESETDONE_MASK),
     54			  MAX_MODULE_SOFTRESET_WAIT, c);
     55
     56	if (c == MAX_MODULE_SOFTRESET_WAIT)
     57		pr_warn("%s: %s: softreset failed (waited %d usec)\n",
     58			__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
     59	else
     60		pr_debug("%s: %s: softreset in %d usec\n", __func__,
     61			 oh->name, c);
     62
     63	return 0;
     64}