// SPDX-License-Identifier: GPL-2.0-only

  /* mac_esp.c: ESP front-end for Macintosh Quadra systems.
   *
   * Adapted from jazz_esp.c and the old mac_esp.c.
   *
   * The pseudo DMA algorithm is based on the one used in NetBSD.
   * See sys/arch/mac68k/obio/esp.c for some background information.
   *
   * Copyright (C) 2007-2008 Finn Thain
   */
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/platform_device.h>
  #include <linux/dma-mapping.h>
  #include <linux/scatterlist.h>
  #include <linux/delay.h>
  #include <linux/io.h>
  #include <linux/nubus.h>

  #include <linux/slab.h>

  
  #include <asm/irq.h>
  #include <asm/dma.h>

  #include <asm/macints.h>
  #include <asm/macintosh.h>

  #include <asm/mac_via.h>

  
  #include <scsi/scsi_host.h>
  
  #include "esp_scsi.h"
  
  #define DRV_MODULE_NAME     "mac_esp"
  #define PFX                 DRV_MODULE_NAME ": "
  #define DRV_VERSION         "1.000"
  #define DRV_MODULE_RELDATE  "Sept 15, 2007"
  
  #define MAC_ESP_IO_BASE          0x50F00000
  #define MAC_ESP_REGS_QUADRA      (MAC_ESP_IO_BASE + 0x10000)
  #define MAC_ESP_REGS_QUADRA2     (MAC_ESP_IO_BASE + 0xF000)
  #define MAC_ESP_REGS_QUADRA3     (MAC_ESP_IO_BASE + 0x18000)
  #define MAC_ESP_REGS_SPACING     0x402
  #define MAC_ESP_PDMA_REG         0xF9800024
  #define MAC_ESP_PDMA_REG_SPACING 0x4
  #define MAC_ESP_PDMA_IO_OFFSET   0x100
  
  #define esp_read8(REG)		mac_esp_read8(esp, REG)
  #define esp_write8(VAL, REG)	mac_esp_write8(esp, VAL, REG)
  
  struct mac_esp_priv {
  	struct esp *esp;
  	void __iomem *pdma_regs;
  	void __iomem *pdma_io;

  };

  static struct esp *esp_chips[2];

  static DEFINE_SPINLOCK(esp_chips_lock);

  
  #define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \

  			       dev_get_drvdata((esp)->dev))

  
  static inline void mac_esp_write8(struct esp *esp, u8 val, unsigned long reg)
  {
  	nubus_writeb(val, esp->regs + reg * 16);
  }
  
  static inline u8 mac_esp_read8(struct esp *esp, unsigned long reg)
  {
  	return nubus_readb(esp->regs + reg * 16);
  }

  static void mac_esp_reset_dma(struct esp *esp)
  {
  	/* Nothing to do. */
  }
  
  static void mac_esp_dma_drain(struct esp *esp)
  {
  	/* Nothing to do. */
  }
  
  static void mac_esp_dma_invalidate(struct esp *esp)
  {
  	/* Nothing to do. */
  }
  
  static int mac_esp_dma_error(struct esp *esp)
  {

  	return esp->send_cmd_error;

  }
  
  static inline int mac_esp_wait_for_empty_fifo(struct esp *esp)
  {

  	int i = 500000;
  
  	do {
  		if (!(esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES))
  			return 0;
  
  		if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
  			return 1;
  
  		udelay(2);
  	} while (--i);
  
  	printk(KERN_ERR PFX "FIFO is not empty (sreg %02x)
  ",
  	       esp_read8(ESP_STATUS));

  	esp->send_cmd_error = 1;

  	return 1;
  }
  
  static inline int mac_esp_wait_for_dreq(struct esp *esp)
  {
  	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
  	int i = 500000;
  
  	do {
  		if (mep->pdma_regs == NULL) {

  			if (via2_scsi_drq_pending())

  				return 0;
  		} else {
  			if (nubus_readl(mep->pdma_regs) & 0x200)
  				return 0;
  		}
  
  		if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
  			return 1;
  
  		udelay(2);
  	} while (--i);
  
  	printk(KERN_ERR PFX "PDMA timeout (sreg %02x)
  ",
  	       esp_read8(ESP_STATUS));

  	esp->send_cmd_error = 1;

  	return 1;
  }
  
  #define MAC_ESP_PDMA_LOOP(operands) \
  	asm volatile ( \

  	     "       tstw %1                   
  " \

  	     "       jbeq 20f                  
  " \
  	     "1:     movew " operands "        
  " \
  	     "2:     movew " operands "        
  " \
  	     "3:     movew " operands "        
  " \
  	     "4:     movew " operands "        
  " \
  	     "5:     movew " operands "        
  " \
  	     "6:     movew " operands "        
  " \
  	     "7:     movew " operands "        
  " \
  	     "8:     movew " operands "        
  " \
  	     "9:     movew " operands "        
  " \
  	     "10:    movew " operands "        
  " \
  	     "11:    movew " operands "        
  " \
  	     "12:    movew " operands "        
  " \
  	     "13:    movew " operands "        
  " \
  	     "14:    movew " operands "        
  " \
  	     "15:    movew " operands "        
  " \
  	     "16:    movew " operands "        
  " \

  	     "       subqw #1,%1               
  " \

  	     "       jbne 1b                   
  " \

  	     "20:    tstw %2                   
  " \

  	     "       jbeq 30f                  
  " \
  	     "21:    movew " operands "        
  " \

  	     "       subqw #1,%2               
  " \

  	     "       jbne 21b                  
  " \

  	     "30:    tstw %3                   
  " \

  	     "       jbeq 40f                  
  " \
  	     "31:    moveb " operands "        
  " \
  	     "32:    nop                       
  " \
  	     "40:                              
  " \
  	     "                                 
  " \
  	     "       .section __ex_table,\"a\" 
  " \
  	     "       .align  4                 
  " \
  	     "       .long   1b,40b            
  " \
  	     "       .long   2b,40b            
  " \
  	     "       .long   3b,40b            
  " \
  	     "       .long   4b,40b            
  " \
  	     "       .long   5b,40b            
  " \
  	     "       .long   6b,40b            
  " \
  	     "       .long   7b,40b            
  " \
  	     "       .long   8b,40b            
  " \
  	     "       .long   9b,40b            
  " \
  	     "       .long  10b,40b            
  " \
  	     "       .long  11b,40b            
  " \
  	     "       .long  12b,40b            
  " \
  	     "       .long  13b,40b            
  " \
  	     "       .long  14b,40b            
  " \
  	     "       .long  15b,40b            
  " \
  	     "       .long  16b,40b            
  " \
  	     "       .long  21b,40b            
  " \
  	     "       .long  31b,40b            
  " \
  	     "       .long  32b,40b            
  " \
  	     "       .previous                 
  " \

  	     : "+a" (addr), "+r" (count32), "+r" (count2) \
  	     : "g" (count1), "a" (mep->pdma_io))

  
  static void mac_esp_send_pdma_cmd(struct esp *esp, u32 addr, u32 esp_count,
  				  u32 dma_count, int write, u8 cmd)
  {
  	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);

  	esp->send_cmd_error = 0;

  
  	if (!write)
  		scsi_esp_cmd(esp, ESP_CMD_FLUSH);
  
  	esp_write8((esp_count >> 0) & 0xFF, ESP_TCLOW);
  	esp_write8((esp_count >> 8) & 0xFF, ESP_TCMED);
  
  	scsi_esp_cmd(esp, cmd);
  
  	do {
  		unsigned int count32 = esp_count >> 5;
  		unsigned int count2 = (esp_count & 0x1F) >> 1;

  		unsigned int count1 = esp_count & 1;

  		unsigned int start_addr = addr;
  
  		if (mac_esp_wait_for_dreq(esp))
  			break;
  
  		if (write) {

  			MAC_ESP_PDMA_LOOP("%4@,%0@+");

  
  			esp_count -= addr - start_addr;
  		} else {
  			unsigned int n;

  			MAC_ESP_PDMA_LOOP("%0@+,%4@");

  
  			if (mac_esp_wait_for_empty_fifo(esp))
  				break;
  
  			n = (esp_read8(ESP_TCMED) << 8) + esp_read8(ESP_TCLOW);
  			addr = start_addr + esp_count - n;
  			esp_count = n;
  		}
  	} while (esp_count);

  }

  static int mac_esp_irq_pending(struct esp *esp)
  {
  	if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
  		return 1;
  	return 0;
  }
  
  static u32 mac_esp_dma_length_limit(struct esp *esp, u32 dma_addr, u32 dma_len)
  {
  	return dma_len > 0xFFFF ? 0xFFFF : dma_len;
  }

  static irqreturn_t mac_scsi_esp_intr(int irq, void *dev_id)
  {
  	int got_intr;
  
  	/*
  	 * This is an edge triggered IRQ, so we have to be careful to
  	 * avoid missing a transition when it is shared by two ESP devices.
  	 */
  
  	do {
  		got_intr = 0;
  		if (esp_chips[0] &&
  		    (mac_esp_read8(esp_chips[0], ESP_STATUS) & ESP_STAT_INTR)) {
  			(void)scsi_esp_intr(irq, esp_chips[0]);
  			got_intr = 1;
  		}
  		if (esp_chips[1] &&
  		    (mac_esp_read8(esp_chips[1], ESP_STATUS) & ESP_STAT_INTR)) {
  			(void)scsi_esp_intr(irq, esp_chips[1]);
  			got_intr = 1;
  		}
  	} while (got_intr);
  
  	return IRQ_HANDLED;
  }

  static struct esp_driver_ops mac_esp_ops = {
  	.esp_write8       = mac_esp_write8,
  	.esp_read8        = mac_esp_read8,

  	.irq_pending      = mac_esp_irq_pending,
  	.dma_length_limit = mac_esp_dma_length_limit,
  	.reset_dma        = mac_esp_reset_dma,
  	.dma_drain        = mac_esp_dma_drain,
  	.dma_invalidate   = mac_esp_dma_invalidate,
  	.send_dma_cmd     = mac_esp_send_pdma_cmd,
  	.dma_error        = mac_esp_dma_error,
  };

  static int esp_mac_probe(struct platform_device *dev)

  {
  	struct scsi_host_template *tpnt = &scsi_esp_template;
  	struct Scsi_Host *host;
  	struct esp *esp;
  	int err;

  	struct mac_esp_priv *mep;
  
  	if (!MACH_IS_MAC)
  		return -ENODEV;

  	if (dev->id > 1)

  		return -ENODEV;
  
  	host = scsi_host_alloc(tpnt, sizeof(struct esp));
  
  	err = -ENOMEM;
  	if (!host)
  		goto fail;
  
  	host->max_id = 8;

  	host->dma_boundary = PAGE_SIZE - 1;

  	esp = shost_priv(host);
  
  	esp->host = host;

  	esp->dev = &dev->dev;

  
  	esp->command_block = kzalloc(16, GFP_KERNEL);
  	if (!esp->command_block)
  		goto fail_unlink;
  	esp->command_block_dma = (dma_addr_t)esp->command_block;
  
  	esp->scsi_id = 7;
  	host->this_id = esp->scsi_id;
  	esp->scsi_id_mask = 1 << esp->scsi_id;
  
  	mep = kzalloc(sizeof(struct mac_esp_priv), GFP_KERNEL);
  	if (!mep)
  		goto fail_free_command_block;
  	mep->esp = esp;
  	platform_set_drvdata(dev, mep);
  
  	switch (macintosh_config->scsi_type) {
  	case MAC_SCSI_QUADRA:
  		esp->cfreq     = 16500000;
  		esp->regs      = (void __iomem *)MAC_ESP_REGS_QUADRA;
  		mep->pdma_io   = esp->regs + MAC_ESP_PDMA_IO_OFFSET;
  		mep->pdma_regs = NULL;
  		break;
  	case MAC_SCSI_QUADRA2:
  		esp->cfreq     = 25000000;
  		esp->regs      = (void __iomem *)(MAC_ESP_REGS_QUADRA2 +
  				 dev->id * MAC_ESP_REGS_SPACING);
  		mep->pdma_io   = esp->regs + MAC_ESP_PDMA_IO_OFFSET;
  		mep->pdma_regs = (void __iomem *)(MAC_ESP_PDMA_REG +
  				 dev->id * MAC_ESP_PDMA_REG_SPACING);
  		nubus_writel(0x1d1, mep->pdma_regs);
  		break;
  	case MAC_SCSI_QUADRA3:
  		/* These quadras have a real DMA controller (the PSC) but we
  		 * don't know how to drive it so we must use PIO instead.
  		 */
  		esp->cfreq     = 25000000;
  		esp->regs      = (void __iomem *)MAC_ESP_REGS_QUADRA3;
  		mep->pdma_io   = NULL;
  		mep->pdma_regs = NULL;
  		break;
  	}

  	esp->fifo_reg = esp->regs + ESP_FDATA * 16;

  
  	esp->ops = &mac_esp_ops;

  	esp->flags = ESP_FLAG_NO_DMA_MAP;

  	if (mep->pdma_io == NULL) {
  		printk(KERN_INFO PFX "using PIO for controller %d
  ", dev->id);
  		esp_write8(0, ESP_TCLOW);
  		esp_write8(0, ESP_TCMED);

  		esp->flags |= ESP_FLAG_DISABLE_SYNC;

  		mac_esp_ops.send_dma_cmd = esp_send_pio_cmd;

  	} else {
  		printk(KERN_INFO PFX "using PDMA for controller %d
  ", dev->id);
  	}
  
  	host->irq = IRQ_MAC_SCSI;

  
  	/* The request_irq() call is intended to succeed for the first device
  	 * and fail for the second device.
  	 */
  	err = request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL);
  	spin_lock(&esp_chips_lock);
  	if (err < 0 && esp_chips[!dev->id] == NULL) {
  		spin_unlock(&esp_chips_lock);
  		goto fail_free_priv;

  	}

  	esp_chips[dev->id] = esp;
  	spin_unlock(&esp_chips_lock);

  	err = scsi_esp_register(esp);

  	if (err)
  		goto fail_free_irq;
  
  	return 0;
  
  fail_free_irq:

  	spin_lock(&esp_chips_lock);
  	esp_chips[dev->id] = NULL;
  	if (esp_chips[!dev->id] == NULL) {
  		spin_unlock(&esp_chips_lock);

  		free_irq(host->irq, NULL);

  	} else
  		spin_unlock(&esp_chips_lock);

  fail_free_priv:
  	kfree(mep);
  fail_free_command_block:
  	kfree(esp->command_block);
  fail_unlink:
  	scsi_host_put(host);
  fail:
  	return err;
  }

  static int esp_mac_remove(struct platform_device *dev)

  {
  	struct mac_esp_priv *mep = platform_get_drvdata(dev);
  	struct esp *esp = mep->esp;
  	unsigned int irq = esp->host->irq;
  
  	scsi_esp_unregister(esp);

  	spin_lock(&esp_chips_lock);

  	esp_chips[dev->id] = NULL;

  	if (esp_chips[!dev->id] == NULL) {
  		spin_unlock(&esp_chips_lock);

  		free_irq(irq, NULL);

  	} else
  		spin_unlock(&esp_chips_lock);

  
  	kfree(mep);
  
  	kfree(esp->command_block);
  
  	scsi_host_put(esp->host);
  
  	return 0;
  }
  
  static struct platform_driver esp_mac_driver = {
  	.probe    = esp_mac_probe,

  	.remove   = esp_mac_remove,

  	.driver   = {

  		.name	= DRV_MODULE_NAME,

  	},
  };

  module_platform_driver(esp_mac_driver);

  
  MODULE_DESCRIPTION("Mac ESP SCSI driver");

  MODULE_AUTHOR("Finn Thain");

  MODULE_LICENSE("GPL v2");

  MODULE_VERSION(DRV_VERSION);

  MODULE_ALIAS("platform:" DRV_MODULE_NAME);