linux/drivers/remoteproc/da8xx_remoteproc.c
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   1/*
   2 * Remote processor machine-specific module for DA8XX
   3 *
   4 * Copyright (C) 2013 Texas Instruments, Inc.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * version 2 as published by the Free Software Foundation.
   9 */
  10
  11#include <linux/bitops.h>
  12#include <linux/clk.h>
  13#include <linux/err.h>
  14#include <linux/interrupt.h>
  15#include <linux/io.h>
  16#include <linux/irq.h>
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/platform_device.h>
  20#include <linux/remoteproc.h>
  21
  22#include <mach/clock.h>   /* for davinci_clk_reset_assert/deassert() */
  23
  24#include "remoteproc_internal.h"
  25
  26static char *da8xx_fw_name;
  27module_param(da8xx_fw_name, charp, S_IRUGO);
  28MODULE_PARM_DESC(da8xx_fw_name,
  29                 "\n\t\tName of DSP firmware file in /lib/firmware"
  30                 " (if not specified defaults to 'rproc-dsp-fw')");
  31
  32/*
  33 * OMAP-L138 Technical References:
  34 * http://www.ti.com/product/omap-l138
  35 */
  36#define SYSCFG_CHIPSIG0 BIT(0)
  37#define SYSCFG_CHIPSIG1 BIT(1)
  38#define SYSCFG_CHIPSIG2 BIT(2)
  39#define SYSCFG_CHIPSIG3 BIT(3)
  40#define SYSCFG_CHIPSIG4 BIT(4)
  41
  42/**
  43 * struct da8xx_rproc - da8xx remote processor instance state
  44 * @rproc: rproc handle
  45 * @dsp_clk: placeholder for platform's DSP clk
  46 * @ack_fxn: chip-specific ack function for ack'ing irq
  47 * @irq_data: ack_fxn function parameter
  48 * @chipsig: virt ptr to DSP interrupt registers (CHIPSIG & CHIPSIG_CLR)
  49 * @bootreg: virt ptr to DSP boot address register (HOST1CFG)
  50 * @irq: irq # used by this instance
  51 */
  52struct da8xx_rproc {
  53        struct rproc *rproc;
  54        struct clk *dsp_clk;
  55        void (*ack_fxn)(struct irq_data *data);
  56        struct irq_data *irq_data;
  57        void __iomem *chipsig;
  58        void __iomem *bootreg;
  59        int irq;
  60};
  61
  62/**
  63 * handle_event() - inbound virtqueue message workqueue function
  64 *
  65 * This function is registered as a kernel thread and is scheduled by the
  66 * kernel handler.
  67 */
  68static irqreturn_t handle_event(int irq, void *p)
  69{
  70        struct rproc *rproc = (struct rproc *)p;
  71
  72        /* Process incoming buffers on all our vrings */
  73        rproc_vq_interrupt(rproc, 0);
  74        rproc_vq_interrupt(rproc, 1);
  75
  76        return IRQ_HANDLED;
  77}
  78
  79/**
  80 * da8xx_rproc_callback() - inbound virtqueue message handler
  81 *
  82 * This handler is invoked directly by the kernel whenever the remote
  83 * core (DSP) has modified the state of a virtqueue.  There is no
  84 * "payload" message indicating the virtqueue index as is the case with
  85 * mailbox-based implementations on OMAP4.  As such, this handler "polls"
  86 * each known virtqueue index for every invocation.
  87 */
  88static irqreturn_t da8xx_rproc_callback(int irq, void *p)
  89{
  90        struct rproc *rproc = (struct rproc *)p;
  91        struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
  92        u32 chipsig;
  93
  94        chipsig = readl(drproc->chipsig);
  95        if (chipsig & SYSCFG_CHIPSIG0) {
  96                /* Clear interrupt level source */
  97                writel(SYSCFG_CHIPSIG0, drproc->chipsig + 4);
  98
  99                /*
 100                 * ACK intr to AINTC.
 101                 *
 102                 * It has already been ack'ed by the kernel before calling
 103                 * this function, but since the ARM<->DSP interrupts in the
 104                 * CHIPSIG register are "level" instead of "pulse" variety,
 105                 * we need to ack it after taking down the level else we'll
 106                 * be called again immediately after returning.
 107                 */
 108                drproc->ack_fxn(drproc->irq_data);
 109
 110                return IRQ_WAKE_THREAD;
 111        }
 112
 113        return IRQ_HANDLED;
 114}
 115
 116static int da8xx_rproc_start(struct rproc *rproc)
 117{
 118        struct device *dev = rproc->dev.parent;
 119        struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
 120        struct clk *dsp_clk = drproc->dsp_clk;
 121
 122        /* hw requires the start (boot) address be on 1KB boundary */
 123        if (rproc->bootaddr & 0x3ff) {
 124                dev_err(dev, "invalid boot address: must be aligned to 1KB\n");
 125
 126                return -EINVAL;
 127        }
 128
 129        writel(rproc->bootaddr, drproc->bootreg);
 130
 131        clk_enable(dsp_clk);
 132        davinci_clk_reset_deassert(dsp_clk);
 133
 134        return 0;
 135}
 136
 137static int da8xx_rproc_stop(struct rproc *rproc)
 138{
 139        struct da8xx_rproc *drproc = rproc->priv;
 140
 141        clk_disable(drproc->dsp_clk);
 142
 143        return 0;
 144}
 145
 146/* kick a virtqueue */
 147static void da8xx_rproc_kick(struct rproc *rproc, int vqid)
 148{
 149        struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
 150
 151        /* Interupt remote proc */
 152        writel(SYSCFG_CHIPSIG2, drproc->chipsig);
 153}
 154
 155static struct rproc_ops da8xx_rproc_ops = {
 156        .start = da8xx_rproc_start,
 157        .stop = da8xx_rproc_stop,
 158        .kick = da8xx_rproc_kick,
 159};
 160
 161static int reset_assert(struct device *dev)
 162{
 163        struct clk *dsp_clk;
 164
 165        dsp_clk = clk_get(dev, NULL);
 166        if (IS_ERR(dsp_clk)) {
 167                dev_err(dev, "clk_get error: %ld\n", PTR_ERR(dsp_clk));
 168                return PTR_ERR(dsp_clk);
 169        }
 170
 171        davinci_clk_reset_assert(dsp_clk);
 172        clk_put(dsp_clk);
 173
 174        return 0;
 175}
 176
 177static int da8xx_rproc_probe(struct platform_device *pdev)
 178{
 179        struct device *dev = &pdev->dev;
 180        struct da8xx_rproc *drproc;
 181        struct rproc *rproc;
 182        struct irq_data *irq_data;
 183        struct resource *bootreg_res;
 184        struct resource *chipsig_res;
 185        struct clk *dsp_clk;
 186        void __iomem *chipsig;
 187        void __iomem *bootreg;
 188        int irq;
 189        int ret;
 190
 191        irq = platform_get_irq(pdev, 0);
 192        if (irq < 0) {
 193                dev_err(dev, "platform_get_irq(pdev, 0) error: %d\n", irq);
 194                return irq;
 195        }
 196
 197        irq_data = irq_get_irq_data(irq);
 198        if (!irq_data) {
 199                dev_err(dev, "irq_get_irq_data(%d): NULL\n", irq);
 200                return -EINVAL;
 201        }
 202
 203        bootreg_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 204        if (!bootreg_res) {
 205                dev_err(dev,
 206                        "platform_get_resource(IORESOURCE_MEM, 0): NULL\n");
 207                return -EADDRNOTAVAIL;
 208        }
 209
 210        chipsig_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 211        if (!chipsig_res) {
 212                dev_err(dev,
 213                        "platform_get_resource(IORESOURCE_MEM, 1): NULL\n");
 214                return -EADDRNOTAVAIL;
 215        }
 216
 217        bootreg = devm_ioremap_resource(dev, bootreg_res);
 218        if (IS_ERR(bootreg))
 219                return PTR_ERR(bootreg);
 220
 221        chipsig = devm_ioremap_resource(dev, chipsig_res);
 222        if (IS_ERR(chipsig))
 223                return PTR_ERR(chipsig);
 224
 225        dsp_clk = devm_clk_get(dev, NULL);
 226        if (IS_ERR(dsp_clk)) {
 227                dev_err(dev, "clk_get error: %ld\n", PTR_ERR(dsp_clk));
 228
 229                return PTR_ERR(dsp_clk);
 230        }
 231
 232        rproc = rproc_alloc(dev, "dsp", &da8xx_rproc_ops, da8xx_fw_name,
 233                sizeof(*drproc));
 234        if (!rproc)
 235                return -ENOMEM;
 236
 237        drproc = rproc->priv;
 238        drproc->rproc = rproc;
 239
 240        platform_set_drvdata(pdev, rproc);
 241
 242        /* everything the ISR needs is now setup, so hook it up */
 243        ret = devm_request_threaded_irq(dev, irq, da8xx_rproc_callback,
 244                                        handle_event, 0, "da8xx-remoteproc",
 245                                        rproc);
 246        if (ret) {
 247                dev_err(dev, "devm_request_threaded_irq error: %d\n", ret);
 248                goto free_rproc;
 249        }
 250
 251        /*
 252         * rproc_add() can end up enabling the DSP's clk with the DSP
 253         * *not* in reset, but da8xx_rproc_start() needs the DSP to be
 254         * held in reset at the time it is called.
 255         */
 256        ret = reset_assert(dev);
 257        if (ret)
 258                goto free_rproc;
 259
 260        drproc->chipsig = chipsig;
 261        drproc->bootreg = bootreg;
 262        drproc->ack_fxn = irq_data->chip->irq_ack;
 263        drproc->irq_data = irq_data;
 264        drproc->irq = irq;
 265        drproc->dsp_clk = dsp_clk;
 266
 267        ret = rproc_add(rproc);
 268        if (ret) {
 269                dev_err(dev, "rproc_add failed: %d\n", ret);
 270                goto free_rproc;
 271        }
 272
 273        return 0;
 274
 275free_rproc:
 276        rproc_put(rproc);
 277
 278        return ret;
 279}
 280
 281static int da8xx_rproc_remove(struct platform_device *pdev)
 282{
 283        struct device *dev = &pdev->dev;
 284        struct rproc *rproc = platform_get_drvdata(pdev);
 285        struct da8xx_rproc *drproc = (struct da8xx_rproc *)rproc->priv;
 286
 287        /*
 288         * It's important to place the DSP in reset before going away,
 289         * since a subsequent insmod of this module may enable the DSP's
 290         * clock before its program/boot-address has been loaded and
 291         * before this module's probe has had a chance to reset the DSP.
 292         * Without the reset, the DSP can lockup permanently when it
 293         * begins executing garbage.
 294         */
 295        reset_assert(dev);
 296
 297        /*
 298         * The devm subsystem might end up releasing things before
 299         * freeing the irq, thus allowing an interrupt to sneak in while
 300         * the device is being removed.  This should prevent that.
 301         */
 302        disable_irq(drproc->irq);
 303
 304        devm_clk_put(dev, drproc->dsp_clk);
 305
 306        rproc_del(rproc);
 307        rproc_put(rproc);
 308
 309        return 0;
 310}
 311
 312static struct platform_driver da8xx_rproc_driver = {
 313        .probe = da8xx_rproc_probe,
 314        .remove = da8xx_rproc_remove,
 315        .driver = {
 316                .name = "davinci-rproc",
 317                .owner = THIS_MODULE,
 318        },
 319};
 320
 321module_platform_driver(da8xx_rproc_driver);
 322
 323MODULE_LICENSE("GPL v2");
 324MODULE_DESCRIPTION("DA8XX Remote Processor control driver");
 325
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