/* sun3x_esp.c: ESP front-end for Sun3x systems.
   *
   * Copyright (C) 2007,2008 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
   */
  
  #include <linux/kernel.h>
  #include <linux/gfp.h>
  #include <linux/types.h>
  #include <linux/delay.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/dma-mapping.h>
  #include <linux/interrupt.h>
  
  #include <asm/sun3x.h>
  #include <asm/io.h>
  #include <asm/dma.h>
  #include <asm/dvma.h>
  
  /* DMA controller reg offsets */
  #define DMA_CSR		0x00UL	/* rw  DMA control/status register    0x00   */
  #define DMA_ADDR        0x04UL	/* rw  DMA transfer address register  0x04   */
  #define DMA_COUNT       0x08UL	/* rw  DMA transfer count register    0x08   */
  #define DMA_TEST        0x0cUL	/* rw  DMA test/debug register        0x0c   */
  
  #include <scsi/scsi_host.h>
  
  #include "esp_scsi.h"
  
  #define DRV_MODULE_NAME		"sun3x_esp"
  #define PFX DRV_MODULE_NAME	": "
  #define DRV_VERSION		"1.000"
  #define DRV_MODULE_RELDATE	"Nov 1, 2007"
  
  /*
   * m68k always assumes readl/writel operate on little endian
   * mmio space; this is wrong at least for Sun3x, so we
   * need to workaround this until a proper way is found
   */
  #if 0
  #define dma_read32(REG) \
  	readl(esp->dma_regs + (REG))
  #define dma_write32(VAL, REG) \
  	writel((VAL), esp->dma_regs + (REG))
  #else
  #define dma_read32(REG) \
  	*(volatile u32 *)(esp->dma_regs + (REG))
  #define dma_write32(VAL, REG) \
  	do { *(volatile u32 *)(esp->dma_regs + (REG)) = (VAL); } while (0)
  #endif
  
  static void sun3x_esp_write8(struct esp *esp, u8 val, unsigned long reg)
  {
  	writeb(val, esp->regs + (reg * 4UL));
  }
  
  static u8 sun3x_esp_read8(struct esp *esp, unsigned long reg)
  {
  	return readb(esp->regs + (reg * 4UL));
  }
  
  static dma_addr_t sun3x_esp_map_single(struct esp *esp, void *buf,
  				      size_t sz, int dir)
  {
  	return dma_map_single(esp->dev, buf, sz, dir);
  }
  
  static int sun3x_esp_map_sg(struct esp *esp, struct scatterlist *sg,
  				  int num_sg, int dir)
  {
  	return dma_map_sg(esp->dev, sg, num_sg, dir);
  }
  
  static void sun3x_esp_unmap_single(struct esp *esp, dma_addr_t addr,
  				  size_t sz, int dir)
  {
  	dma_unmap_single(esp->dev, addr, sz, dir);
  }
  
  static void sun3x_esp_unmap_sg(struct esp *esp, struct scatterlist *sg,
  			      int num_sg, int dir)
  {
  	dma_unmap_sg(esp->dev, sg, num_sg, dir);
  }
  
  static int sun3x_esp_irq_pending(struct esp *esp)
  {
  	if (dma_read32(DMA_CSR) & (DMA_HNDL_INTR | DMA_HNDL_ERROR))
  		return 1;
  	return 0;
  }
  
  static void sun3x_esp_reset_dma(struct esp *esp)
  {
  	u32 val;
  
  	val = dma_read32(DMA_CSR);
  	dma_write32(val | DMA_RST_SCSI, DMA_CSR);
  	dma_write32(val & ~DMA_RST_SCSI, DMA_CSR);
  
  	/* Enable interrupts.  */
  	val = dma_read32(DMA_CSR);
  	dma_write32(val | DMA_INT_ENAB, DMA_CSR);
  }
  
  static void sun3x_esp_dma_drain(struct esp *esp)
  {
  	u32 csr;
  	int lim;
  
  	csr = dma_read32(DMA_CSR);
  	if (!(csr & DMA_FIFO_ISDRAIN))
  		return;
  
  	dma_write32(csr | DMA_FIFO_STDRAIN, DMA_CSR);
  
  	lim = 1000;
  	while (dma_read32(DMA_CSR) & DMA_FIFO_ISDRAIN) {
  		if (--lim == 0) {
  			printk(KERN_ALERT PFX "esp%d: DMA will not drain!
  ",
  			       esp->host->unique_id);
  			break;
  		}
  		udelay(1);
  	}
  }
  
  static void sun3x_esp_dma_invalidate(struct esp *esp)
  {
  	u32 val;
  	int lim;
  
  	lim = 1000;
  	while ((val = dma_read32(DMA_CSR)) & DMA_PEND_READ) {
  		if (--lim == 0) {
  			printk(KERN_ALERT PFX "esp%d: DMA will not "
  			       "invalidate!
  ", esp->host->unique_id);
  			break;
  		}
  		udelay(1);
  	}
  
  	val &= ~(DMA_ENABLE | DMA_ST_WRITE | DMA_BCNT_ENAB);
  	val |= DMA_FIFO_INV;
  	dma_write32(val, DMA_CSR);
  	val &= ~DMA_FIFO_INV;
  	dma_write32(val, DMA_CSR);
  }
  
  static void sun3x_esp_send_dma_cmd(struct esp *esp, u32 addr, u32 esp_count,
  				  u32 dma_count, int write, u8 cmd)
  {
  	u32 csr;
  
  	BUG_ON(!(cmd & ESP_CMD_DMA));
  
  	sun3x_esp_write8(esp, (esp_count >> 0) & 0xff, ESP_TCLOW);
  	sun3x_esp_write8(esp, (esp_count >> 8) & 0xff, ESP_TCMED);
  	csr = dma_read32(DMA_CSR);
  	csr |= DMA_ENABLE;
  	if (write)
  		csr |= DMA_ST_WRITE;
  	else
  		csr &= ~DMA_ST_WRITE;
  	dma_write32(csr, DMA_CSR);
  	dma_write32(addr, DMA_ADDR);
  
  	scsi_esp_cmd(esp, cmd);
  }
  
  static int sun3x_esp_dma_error(struct esp *esp)
  {
  	u32 csr = dma_read32(DMA_CSR);
  
  	if (csr & DMA_HNDL_ERROR)
  		return 1;
  
  	return 0;
  }
  
  static const struct esp_driver_ops sun3x_esp_ops = {
  	.esp_write8	=	sun3x_esp_write8,
  	.esp_read8	=	sun3x_esp_read8,
  	.map_single	=	sun3x_esp_map_single,
  	.map_sg		=	sun3x_esp_map_sg,
  	.unmap_single	=	sun3x_esp_unmap_single,
  	.unmap_sg	=	sun3x_esp_unmap_sg,
  	.irq_pending	=	sun3x_esp_irq_pending,
  	.reset_dma	=	sun3x_esp_reset_dma,
  	.dma_drain	=	sun3x_esp_dma_drain,
  	.dma_invalidate	=	sun3x_esp_dma_invalidate,
  	.send_dma_cmd	=	sun3x_esp_send_dma_cmd,
  	.dma_error	=	sun3x_esp_dma_error,
  };
  
  static int esp_sun3x_probe(struct platform_device *dev)
  {
  	struct scsi_host_template *tpnt = &scsi_esp_template;
  	struct Scsi_Host *host;
  	struct esp *esp;
  	struct resource *res;
  	int err = -ENOMEM;
  
  	host = scsi_host_alloc(tpnt, sizeof(struct esp));
  	if (!host)
  		goto fail;
  
  	host->max_id = 8;
  	esp = shost_priv(host);
  
  	esp->host = host;
  	esp->dev = dev;
  	esp->ops = &sun3x_esp_ops;
  
  	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
  	if (!res || !res->start)
  		goto fail_unlink;
  
  	esp->regs = ioremap_nocache(res->start, 0x20);
  	if (!esp->regs)
  		goto fail_unmap_regs;
  
  	res = platform_get_resource(dev, IORESOURCE_MEM, 1);
  	if (!res || !res->start)
  		goto fail_unmap_regs;
  
  	esp->dma_regs = ioremap_nocache(res->start, 0x10);
  
  	esp->command_block = dma_alloc_coherent(esp->dev, 16,
  						&esp->command_block_dma,
  						GFP_KERNEL);
  	if (!esp->command_block)
  		goto fail_unmap_regs_dma;
  
  	host->irq = platform_get_irq(dev, 0);
  	err = request_irq(host->irq, scsi_esp_intr, IRQF_SHARED,
  			  "SUN3X ESP", esp);
  	if (err < 0)
  		goto fail_unmap_command_block;
  
  	esp->scsi_id = 7;
  	esp->host->this_id = esp->scsi_id;
  	esp->scsi_id_mask = (1 << esp->scsi_id);
  	esp->cfreq = 20000000;
  
  	dev_set_drvdata(&dev->dev, esp);
  
  	err = scsi_esp_register(esp, &dev->dev);
  	if (err)
  		goto fail_free_irq;
  
  	return 0;
  
  fail_free_irq:
  	free_irq(host->irq, esp);
  fail_unmap_command_block:
  	dma_free_coherent(esp->dev, 16,
  			  esp->command_block,
  			  esp->command_block_dma);
  fail_unmap_regs_dma:
  	iounmap(esp->dma_regs);
  fail_unmap_regs:
  	iounmap(esp->regs);
  fail_unlink:
  	scsi_host_put(host);
  fail:
  	return err;
  }
  
  static int esp_sun3x_remove(struct platform_device *dev)
  {
  	struct esp *esp = dev_get_drvdata(&dev->dev);
  	unsigned int irq = esp->host->irq;
  	u32 val;
  
  	scsi_esp_unregister(esp);
  
  	/* Disable interrupts.  */
  	val = dma_read32(DMA_CSR);
  	dma_write32(val & ~DMA_INT_ENAB, DMA_CSR);
  
  	free_irq(irq, esp);
  	dma_free_coherent(esp->dev, 16,
  			  esp->command_block,
  			  esp->command_block_dma);
  
  	scsi_host_put(esp->host);
  
  	return 0;
  }
  
  static struct platform_driver esp_sun3x_driver = {
  	.probe          = esp_sun3x_probe,
  	.remove         = esp_sun3x_remove,
  	.driver = {
  		.name   = "sun3x_esp",
  		.owner	= THIS_MODULE,
  	},
  };
  
  static int __init sun3x_esp_init(void)
  {
  	return platform_driver_register(&esp_sun3x_driver);
  }
  
  static void __exit sun3x_esp_exit(void)
  {
  	platform_driver_unregister(&esp_sun3x_driver);
  }
  
  MODULE_DESCRIPTION("Sun3x ESP SCSI driver");
  MODULE_AUTHOR("Thomas Bogendoerfer (tsbogend@alpha.franken.de)");
  MODULE_LICENSE("GPL");
  MODULE_VERSION(DRV_VERSION);
  
  module_init(sun3x_esp_init);
  module_exit(sun3x_esp_exit);
  MODULE_ALIAS("platform:sun3x_esp");