drivers/remoteproc/da8xx_remoteproc.c

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