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Linux/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                  "\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  */
 52 struct 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  */
 68 static 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  */
 88 static 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 
116 static 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 
137 static 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 */
147 static 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 
155 static struct rproc_ops da8xx_rproc_ops = {
156         .start = da8xx_rproc_start,
157         .stop = da8xx_rproc_stop,
158         .kick = da8xx_rproc_kick,
159 };
160 
161 static 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 
177 static 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         bootreg = devm_ioremap_resource(dev, bootreg_res);
205         if (IS_ERR(bootreg))
206                 return PTR_ERR(bootreg);
207 
208         chipsig_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
209         chipsig = devm_ioremap_resource(dev, chipsig_res);
210         if (IS_ERR(chipsig))
211                 return PTR_ERR(chipsig);
212 
213         dsp_clk = devm_clk_get(dev, NULL);
214         if (IS_ERR(dsp_clk)) {
215                 dev_err(dev, "clk_get error: %ld\n", PTR_ERR(dsp_clk));
216 
217                 return PTR_ERR(dsp_clk);
218         }
219 
220         rproc = rproc_alloc(dev, "dsp", &da8xx_rproc_ops, da8xx_fw_name,
221                 sizeof(*drproc));
222         if (!rproc)
223                 return -ENOMEM;
224 
225         drproc = rproc->priv;
226         drproc->rproc = rproc;
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                 .owner = THIS_MODULE,
304         },
305 };
306 
307 module_platform_driver(da8xx_rproc_driver);
308 
309 MODULE_LICENSE("GPL v2");
310 MODULE_DESCRIPTION("DA8XX Remote Processor control driver");
311 

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