uio_pruss.c

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/*
 * Programmable Real-Time Unit Sub System (PRUSS) UIO driver (uio_pruss)
 *
 * This driver exports PRUSS host event out interrupts and PRUSS, L3 RAM,
 * and DDR RAM to user space for applications interacting with PRUSS firmware
 *
 * Copyright (C) 2010-11 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
#include <linux/device.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/uio_driver.h>
#include <linux/platform_data/uio_pruss.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <mach/sram.h>

#define DRV_NAME "pruss_uio"
#define DRV_VERSION "1.0"

static int sram_pool_sz = SZ_16K;
module_param(sram_pool_sz, int, 0);
MODULE_PARM_DESC(sram_pool_sz, "sram pool size to allocate ");

static int extram_pool_sz = SZ_256K;
module_param(extram_pool_sz, int, 0);
MODULE_PARM_DESC(extram_pool_sz, "external ram pool size to allocate");

/*
 * Host event IRQ numbers from PRUSS - PRUSS can generate up to 8 interrupt
 * events to AINTC of ARM host processor - which can be used for IPC b/w PRUSS
 * firmware and user space application, async notification from PRU firmware
 * to user space application
 * 3    PRU_EVTOUT0
 * 4    PRU_EVTOUT1
 * 5    PRU_EVTOUT2
 * 6    PRU_EVTOUT3
 * 7    PRU_EVTOUT4
 * 8    PRU_EVTOUT5
 * 9    PRU_EVTOUT6
 * 10   PRU_EVTOUT7
*/
#define MAX_PRUSS_EVT   8

#define PINTC_HIDISR    0x0038
#define PINTC_HIPIR 0x0900
#define HIPIR_NOPEND    0x80000000
#define PINTC_HIER  0x1500

struct uio_pruss_dev {
    struct uio_info *info;
    struct clk *pruss_clk;
    dma_addr_t sram_paddr;
    dma_addr_t ddr_paddr;
    void __iomem *prussio_vaddr;
    void *sram_vaddr;
    void *ddr_vaddr;
    unsigned int hostirq_start;
    unsigned int pintc_base;
};

static irqreturn_t pruss_handler(int irq, struct uio_info *info)
{
    struct uio_pruss_dev *gdev = info->priv;
    int intr_bit = (irq - gdev->hostirq_start + 2);
    int val, intr_mask = (1 << intr_bit);
    void __iomem *base = gdev->prussio_vaddr + gdev->pintc_base;
    void __iomem *intren_reg = base + PINTC_HIER;
    void __iomem *intrdis_reg = base + PINTC_HIDISR;
    void __iomem *intrstat_reg = base + PINTC_HIPIR + (intr_bit << 2);

    val = ioread32(intren_reg);
    /* Is interrupt enabled and active ? */
    if (!(val & intr_mask) && (ioread32(intrstat_reg) & HIPIR_NOPEND))
        return IRQ_NONE;
    /* Disable interrupt */
    iowrite32(intr_bit, intrdis_reg);
    return IRQ_HANDLED;
}

static void pruss_cleanup(struct platform_device *dev,
            struct uio_pruss_dev *gdev)
{
    int cnt;
    struct uio_info *p = gdev->info;

    for (cnt = 0; cnt < MAX_PRUSS_EVT; cnt++, p++) {
        uio_unregister_device(p);
        kfree(p->name);
    }
    iounmap(gdev->prussio_vaddr);
    if (gdev->ddr_vaddr) {
        dma_free_coherent(&dev->dev, extram_pool_sz, gdev->ddr_vaddr,
            gdev->ddr_paddr);
    }
    if (gdev->sram_vaddr)
        sram_free(gdev->sram_vaddr, sram_pool_sz);
    kfree(gdev->info);
    clk_put(gdev->pruss_clk);
    kfree(gdev);
}

static int __devinit pruss_probe(struct platform_device *dev)
{
    struct uio_info *p;
    struct uio_pruss_dev *gdev;
    struct resource *regs_prussio;
    int ret = -ENODEV, cnt = 0, len;
    struct uio_pruss_pdata *pdata = dev->dev.platform_data;

    gdev = kzalloc(sizeof(struct uio_pruss_dev), GFP_KERNEL);
    if (!gdev)
        return -ENOMEM;

    gdev->info = kzalloc(sizeof(*p) * MAX_PRUSS_EVT, GFP_KERNEL);
    if (!gdev->info) {
        kfree(gdev);
        return -ENOMEM;
    }
    /* Power on PRU in case its not done as part of boot-loader */
    gdev->pruss_clk = clk_get(&dev->dev, "pruss");
    if (IS_ERR(gdev->pruss_clk)) {
        dev_err(&dev->dev, "Failed to get clock\n");
        kfree(gdev->info);
        kfree(gdev);
        ret = PTR_ERR(gdev->pruss_clk);
        return ret;
    } else {
        clk_enable(gdev->pruss_clk);
    }

    regs_prussio = platform_get_resource(dev, IORESOURCE_MEM, 0);
    if (!regs_prussio) {
        dev_err(&dev->dev, "No PRUSS I/O resource specified\n");
        goto out_free;
    }

    if (!regs_prussio->start) {
        dev_err(&dev->dev, "Invalid memory resource\n");
        goto out_free;
    }

    gdev->sram_vaddr = sram_alloc(sram_pool_sz, &(gdev->sram_paddr));
    if (!gdev->sram_vaddr) {
        dev_err(&dev->dev, "Could not allocate SRAM pool\n");
        goto out_free;
    }

    gdev->ddr_vaddr = dma_alloc_coherent(&dev->dev, extram_pool_sz,
                &(gdev->ddr_paddr), GFP_KERNEL | GFP_DMA);
    if (!gdev->ddr_vaddr) {
        dev_err(&dev->dev, "Could not allocate external memory\n");
        goto out_free;
    }

    len = resource_size(regs_prussio);
    gdev->prussio_vaddr = ioremap(regs_prussio->start, len);
    if (!gdev->prussio_vaddr) {
        dev_err(&dev->dev, "Can't remap PRUSS I/O  address range\n");
        goto out_free;
    }

    gdev->pintc_base = pdata->pintc_base;
    gdev->hostirq_start = platform_get_irq(dev, 0);

    for (cnt = 0, p = gdev->info; cnt < MAX_PRUSS_EVT; cnt++, p++) {
        p->mem[0].addr = regs_prussio->start;
        p->mem[0].size = resource_size(regs_prussio);
        p->mem[0].memtype = UIO_MEM_PHYS;

        p->mem[1].addr = gdev->sram_paddr;
        p->mem[1].size = sram_pool_sz;
        p->mem[1].memtype = UIO_MEM_PHYS;

        p->mem[2].addr = gdev->ddr_paddr;
        p->mem[2].size = extram_pool_sz;
        p->mem[2].memtype = UIO_MEM_PHYS;

        p->name = kasprintf(GFP_KERNEL, "pruss_evt%d", cnt);
        p->version = DRV_VERSION;

        /* Register PRUSS IRQ lines */
        p->irq = gdev->hostirq_start + cnt;
        p->handler = pruss_handler;
        p->priv = gdev;

        ret = uio_register_device(&dev->dev, p);
        if (ret < 0)
            goto out_free;
    }

    platform_set_drvdata(dev, gdev);
    return 0;

out_free:
    pruss_cleanup(dev, gdev);
    return ret;
}

static int __devexit pruss_remove(struct platform_device *dev)
{
    struct uio_pruss_dev *gdev = platform_get_drvdata(dev);

    pruss_cleanup(dev, gdev);
    platform_set_drvdata(dev, NULL);
    return 0;
}

static struct platform_driver pruss_driver = {
    .probe = pruss_probe,
    .remove = __devexit_p(pruss_remove),
    .driver = {
           .name = DRV_NAME,
           .owner = THIS_MODULE,
           },
};

module_platform_driver(pruss_driver);

MODULE_LICENSE("GPL v2");
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("Amit Chatterjee <[email protected]>");
MODULE_AUTHOR("Pratheesh Gangadhar <[email protected]>");