/*
   * 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 <linux/genalloc.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;
  	unsigned long sram_vaddr;
  	void *ddr_vaddr;
  	unsigned int hostirq_start;
  	unsigned int pintc_base;
  	struct gen_pool *sram_pool;
  };
  
  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)
  		gen_pool_free(gdev->sram_pool,
  			      gdev->sram_vaddr,
  			      sram_pool_sz);
  	kfree(gdev->info);
  	clk_put(gdev->pruss_clk);
  	kfree(gdev);
  }
  
  static int 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_get_platdata(&dev->dev);
  
  	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
  ");
  		ret = PTR_ERR(gdev->pruss_clk);
  		kfree(gdev->info);
  		kfree(gdev);
  		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
  ");
  		goto out_free;
  	}
  
  	if (!regs_prussio->start) {
  		dev_err(&dev->dev, "Invalid memory resource
  ");
  		goto out_free;
  	}
  
  	if (pdata->sram_pool) {
  		gdev->sram_pool = pdata->sram_pool;
  		gdev->sram_vaddr =
  			(unsigned long)gen_pool_dma_alloc(gdev->sram_pool,
  					sram_pool_sz, &gdev->sram_paddr);
  		if (!gdev->sram_vaddr) {
  			dev_err(&dev->dev, "Could not allocate SRAM pool
  ");
  			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
  ");
  		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
  ");
  		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 pruss_remove(struct platform_device *dev)
  {
  	struct uio_pruss_dev *gdev = platform_get_drvdata(dev);
  
  	pruss_cleanup(dev, gdev);
  	return 0;
  }
  
  static struct platform_driver pruss_driver = {
  	.probe = pruss_probe,
  	.remove = 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 <amit.chatterjee@ti.com>");
  MODULE_AUTHOR("Pratheesh Gangadhar <pratheesh@ti.com>");