drivers/firewire/init_ohci1394_dma.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * init_ohci1394_dma.c - Initializes physical DMA on all OHCI 1394 controllers
  *
  * Copyright (C) 2006-2007      Bernhard Kaindl <bk@suse.de>
  *
  * Derived from drivers/ieee1394/ohci1394.c and arch/x86/kernel/early-quirks.c
  * this file has functions to:
  * - scan the PCI very early on boot for all OHCI 1394-compliant controllers
  * - reset and initialize them and make them join the IEEE1394 bus and
  * - enable physical DMA on them to allow remote debugging
  *
  * All code and data is marked as __init and __initdata, respective as
  * during boot, all OHCI1394 controllers may be claimed by the firewire
  * stack and at this point, this code should not touch them anymore.
  *
  * To use physical DMA after the initialization of the firewire stack,
  * be sure that the stack enables it and (re-)attach after the bus reset
  * which may be caused by the firewire stack initialization.
  */

 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>		/* for PCI defines */
 #include <linux/string.h>

 #include <asm/pci-direct.h>	/* for direct PCI config space access */
 #include <asm/fixmap.h>

 #include <linux/init_ohci1394_dma.h>
 #include "ohci.h"

 int __initdata init_ohci1394_dma_early;

 struct ohci {
 	void __iomem *registers;
 };

 static inline void reg_write(const struct ohci *ohci, int offset, u32 data)
 {
 	writel(data, ohci->registers + offset);
 }

 static inline u32 reg_read(const struct ohci *ohci, int offset)
 {
 	return readl(ohci->registers + offset);
 }

 #define OHCI_LOOP_COUNT		100	/* Number of loops for reg read waits */

 /* Reads a PHY register of an OHCI-1394 controller */
 static inline u8 __init get_phy_reg(struct ohci *ohci, u8 addr)
 {
 	int i;
 	u32 r;

 	reg_write(ohci, OHCI1394_PhyControl, (addr << 8) | 0x00008000);

 	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
 		if (reg_read(ohci, OHCI1394_PhyControl) & 0x80000000)
 			break;
 		mdelay(1);
 	}
 	r = reg_read(ohci, OHCI1394_PhyControl);

 	return (r & 0x00ff0000) >> 16;
 }

 /* Writes to a PHY register of an OHCI-1394 controller */
 static inline void __init set_phy_reg(struct ohci *ohci, u8 addr, u8 data)
 {
 	int i;

 	reg_write(ohci, OHCI1394_PhyControl, (addr << 8) | data | 0x00004000);

 	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
 		if (!(reg_read(ohci, OHCI1394_PhyControl) & 0x00004000))
 			break;
 		mdelay(1);
 	}
 }

 /* Resets an OHCI-1394 controller (for sane state before initialization) */
 static inline void __init init_ohci1394_soft_reset(struct ohci *ohci)
 {
 	int i;

 	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_softReset);

 	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
 		if (!(reg_read(ohci, OHCI1394_HCControlSet)
 				   & OHCI1394_HCControl_softReset))
 			break;
 		mdelay(1);
 	}
 }

 #define OHCI1394_MAX_AT_REQ_RETRIES	0xf
 #define OHCI1394_MAX_AT_RESP_RETRIES	0x2
 #define OHCI1394_MAX_PHYS_RESP_RETRIES	0x8

 /* Basic OHCI-1394 register and port inititalization */
 static inline void __init init_ohci1394_initialize(struct ohci *ohci)
 {
 	u32 bus_options;
 	int num_ports, i;

 	/* Put some defaults to these undefined bus options */
 	bus_options = reg_read(ohci, OHCI1394_BusOptions);
 	bus_options |=  0x60000000; /* Enable CMC and ISC */
 	bus_options &= ~0x00ff0000; /* XXX: Set cyc_clk_acc to zero for now */
 	bus_options &= ~0x18000000; /* Disable PMC and BMC */
 	reg_write(ohci, OHCI1394_BusOptions, bus_options);

 	/* Set the bus number */
 	reg_write(ohci, OHCI1394_NodeID, 0x0000ffc0);

 	/* Enable posted writes */
 	reg_write(ohci, OHCI1394_HCControlSet,
 			OHCI1394_HCControl_postedWriteEnable);

 	/* Clear link control register */
 	reg_write(ohci, OHCI1394_LinkControlClear, 0xffffffff);

 	/* enable phys */
 	reg_write(ohci, OHCI1394_LinkControlSet,
 			OHCI1394_LinkControl_rcvPhyPkt);

 	/* Don't accept phy packets into AR request context */
 	reg_write(ohci, OHCI1394_LinkControlClear, 0x00000400);

 	/* Clear the Isochonouys interrupt masks */
 	reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, 0xffffffff);
 	reg_write(ohci, OHCI1394_IsoRecvIntEventClear, 0xffffffff);
 	reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, 0xffffffff);
 	reg_write(ohci, OHCI1394_IsoXmitIntEventClear, 0xffffffff);

 	/* Accept asynchronous transfer requests from all nodes for now */
 	reg_write(ohci, OHCI1394_AsReqFilterHiSet, 0x80000000);

 	/* Specify asynchronous transfer retries */
 	reg_write(ohci, OHCI1394_ATRetries,
 		  OHCI1394_MAX_AT_REQ_RETRIES |
 		  (OHCI1394_MAX_AT_RESP_RETRIES<<4) |
 		  (OHCI1394_MAX_PHYS_RESP_RETRIES<<8));

 	/* We don't want hardware swapping */
 	reg_write(ohci, OHCI1394_HCControlClear,
 		  OHCI1394_HCControl_noByteSwapData);

 	/* Enable link */
 	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_linkEnable);

 	/* If anything is connected to a port, make sure it is enabled */
 	num_ports = get_phy_reg(ohci, 2) & 0xf;
 	for (i = 0; i < num_ports; i++) {
 		unsigned int status;

 		set_phy_reg(ohci, 7, i);
 		status = get_phy_reg(ohci, 8);

 		if (status & 0x20)
 			set_phy_reg(ohci, 8, status & ~1);
 	}
 }

 /**
  * init_ohci1394_wait_for_busresets - wait until bus resets are completed
  *
  * OHCI1394 initialization itself and any device going on- or offline
  * and any cable issue cause a IEEE1394 bus reset. The OHCI1394 spec
  * specifies that physical DMA is disabled on each bus reset and it
  * has to be enabled after each bus reset when needed. We resort
  * to polling here because on early boot, we have no interrupts.
  */
 static inline void __init init_ohci1394_wait_for_busresets(struct ohci *ohci)
 {
 	int i, events;

 	for (i = 0; i < 9; i++) {
 		mdelay(200);
 		events = reg_read(ohci, OHCI1394_IntEventSet);
 		if (events & OHCI1394_busReset)
 			reg_write(ohci, OHCI1394_IntEventClear,
 					OHCI1394_busReset);
 	}
 }

 /**
  * init_ohci1394_enable_physical_dma - Enable physical DMA for remote debugging
  * This enables remote DMA access over IEEE1394 from every host for the low
  * 4GB of address space. DMA accesses above 4GB are not available currently.
  */
 static inline void __init init_ohci1394_enable_physical_dma(struct ohci *ohci)
 {
 	reg_write(ohci, OHCI1394_PhyReqFilterHiSet, 0xffffffff);
 	reg_write(ohci, OHCI1394_PhyReqFilterLoSet, 0xffffffff);
 	reg_write(ohci, OHCI1394_PhyUpperBound, 0xffff0000);
 }

 /**
  * init_ohci1394_reset_and_init_dma - init controller and enable DMA
  * This initializes the given controller and enables physical DMA engine in it.
  */
 static inline void __init init_ohci1394_reset_and_init_dma(struct ohci *ohci)
 {
 	/* Start off with a soft reset, clears everything to a sane state. */
 	init_ohci1394_soft_reset(ohci);

 	/* Accessing some registers without LPS enabled may cause lock up */
 	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_LPS);

 	/* Disable and clear interrupts */
 	reg_write(ohci, OHCI1394_IntEventClear, 0xffffffff);
 	reg_write(ohci, OHCI1394_IntMaskClear, 0xffffffff);

 	mdelay(50); /* Wait 50msec to make sure we have full link enabled */

 	init_ohci1394_initialize(ohci);
 	/*
 	 * The initialization causes at least one IEEE1394 bus reset. Enabling
 	 * physical DMA only works *after* *all* bus resets have calmed down:
 	 */
 	init_ohci1394_wait_for_busresets(ohci);

 	/* We had to wait and do this now if we want to debug early problems */
 	init_ohci1394_enable_physical_dma(ohci);
 }

 /**
  * init_ohci1394_controller - Map the registers of the controller and init DMA
  * This maps the registers of the specified controller and initializes it
  */
 static inline void __init init_ohci1394_controller(int num, int slot, int func)
 {
 	unsigned long ohci_base;
 	struct ohci ohci;

 	printk(KERN_INFO "init_ohci1394_dma: initializing OHCI-1394"
 			 " at %02x:%02x.%x\n", num, slot, func);

 	ohci_base = read_pci_config(num, slot, func, PCI_BASE_ADDRESS_0+(0<<2))
 						   & PCI_BASE_ADDRESS_MEM_MASK;

 	set_fixmap_nocache(FIX_OHCI1394_BASE, ohci_base);

 	ohci.registers = (void __iomem *)fix_to_virt(FIX_OHCI1394_BASE);

 	init_ohci1394_reset_and_init_dma(&ohci);
 }

 /**
  * debug_init_ohci1394_dma - scan for OHCI1394 controllers and init DMA on them
  * Scans the whole PCI space for OHCI1394 controllers and inits DMA on them
  */
 void __init init_ohci1394_dma_on_all_controllers(void)
 {
 	int num, slot, func;
 	u32 class;

 	if (!early_pci_allowed())
 		return;

 	/* Poor man's PCI discovery, the only thing we can do at early boot */
 	for (num = 0; num < 32; num++) {
 		for (slot = 0; slot < 32; slot++) {
 			for (func = 0; func < 8; func++) {
 				class = read_pci_config(num, slot, func,
 							PCI_CLASS_REVISION);
 				if (class == 0xffffffff)
 					continue; /* No device at this func */

 				if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
 					continue; /* Not an OHCI-1394 device */

 				init_ohci1394_controller(num, slot, func);
 				break; /* Assume one controller per device */
 			}
 		}
 	}
 	printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI DMA\n");
 }

 /**
  * setup_init_ohci1394_early - enables early OHCI1394 DMA initialization
  */
 static int __init setup_ohci1394_dma(char *opt)
 {
 	if (!strcmp(opt, "early"))
 		init_ohci1394_dma_early = 1;
 	return 0;
 }

 /* passing ohci1394_dma=early on boot causes early OHCI1394 DMA initialization */
 early_param("ohci1394_dma", setup_ohci1394_dma);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* init_ohci1394_dma.c - Initializes physical DMA on all OHCI 1394 controllers
	*
	* Copyright (C) 2006-2007 Bernhard Kaindl <bk@suse.de>
	*
	* Derived from drivers/ieee1394/ohci1394.c and arch/x86/kernel/early-quirks.c
	* this file has functions to:
	* - scan the PCI very early on boot for all OHCI 1394-compliant controllers
	* - reset and initialize them and make them join the IEEE1394 bus and
	* - enable physical DMA on them to allow remote debugging
	*
	* All code and data is marked as __init and __initdata, respective as
	* during boot, all OHCI1394 controllers may be claimed by the firewire
	* stack and at this point, this code should not touch them anymore.
	*
	* To use physical DMA after the initialization of the firewire stack,
	* be sure that the stack enables it and (re-)attach after the bus reset
	* which may be caused by the firewire stack initialization.
	*/

	#include <linux/delay.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/pci.h> /* for PCI defines */
	#include <linux/string.h>

	#include <asm/pci-direct.h> /* for direct PCI config space access */
	#include <asm/fixmap.h>

	#include <linux/init_ohci1394_dma.h>
	#include "ohci.h"

	int __initdata init_ohci1394_dma_early;

	struct ohci {
	void __iomem *registers;
	};

	static inline void reg_write(const struct ohci *ohci, int offset, u32 data)
	{
	writel(data, ohci->registers + offset);
	}

	static inline u32 reg_read(const struct ohci *ohci, int offset)
	{
	return readl(ohci->registers + offset);
	}

	#define OHCI_LOOP_COUNT 100 /* Number of loops for reg read waits */

	/* Reads a PHY register of an OHCI-1394 controller */
	static inline u8 __init get_phy_reg(struct ohci *ohci, u8 addr)
	{
	int i;
	u32 r;

	reg_write(ohci, OHCI1394_PhyControl, (addr << 8) \| 0x00008000);

	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
	if (reg_read(ohci, OHCI1394_PhyControl) & 0x80000000)
	break;
	mdelay(1);
	}
	r = reg_read(ohci, OHCI1394_PhyControl);

	return (r & 0x00ff0000) >> 16;
	}

	/* Writes to a PHY register of an OHCI-1394 controller */
	static inline void __init set_phy_reg(struct ohci *ohci, u8 addr, u8 data)
	{
	int i;

	reg_write(ohci, OHCI1394_PhyControl, (addr << 8) \| data \| 0x00004000);

	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
	if (!(reg_read(ohci, OHCI1394_PhyControl) & 0x00004000))
	break;
	mdelay(1);
	}
	}

	/* Resets an OHCI-1394 controller (for sane state before initialization) */
	static inline void __init init_ohci1394_soft_reset(struct ohci *ohci)
	{
	int i;

	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_softReset);

	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
	if (!(reg_read(ohci, OHCI1394_HCControlSet)
	& OHCI1394_HCControl_softReset))
	break;
	mdelay(1);
	}
	}

	#define OHCI1394_MAX_AT_REQ_RETRIES 0xf
	#define OHCI1394_MAX_AT_RESP_RETRIES 0x2
	#define OHCI1394_MAX_PHYS_RESP_RETRIES 0x8

	/* Basic OHCI-1394 register and port inititalization */
	static inline void __init init_ohci1394_initialize(struct ohci *ohci)
	{
	u32 bus_options;
	int num_ports, i;

	/* Put some defaults to these undefined bus options */
	bus_options = reg_read(ohci, OHCI1394_BusOptions);
	bus_options \|= 0x60000000; /* Enable CMC and ISC */
	bus_options &= ~0x00ff0000; /* XXX: Set cyc_clk_acc to zero for now */
	bus_options &= ~0x18000000; /* Disable PMC and BMC */
	reg_write(ohci, OHCI1394_BusOptions, bus_options);

	/* Set the bus number */
	reg_write(ohci, OHCI1394_NodeID, 0x0000ffc0);

	/* Enable posted writes */
	reg_write(ohci, OHCI1394_HCControlSet,
	OHCI1394_HCControl_postedWriteEnable);

	/* Clear link control register */
	reg_write(ohci, OHCI1394_LinkControlClear, 0xffffffff);

	/* enable phys */
	reg_write(ohci, OHCI1394_LinkControlSet,
	OHCI1394_LinkControl_rcvPhyPkt);

	/* Don't accept phy packets into AR request context */
	reg_write(ohci, OHCI1394_LinkControlClear, 0x00000400);

	/* Clear the Isochonouys interrupt masks */
	reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, 0xffffffff);
	reg_write(ohci, OHCI1394_IsoRecvIntEventClear, 0xffffffff);
	reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, 0xffffffff);
	reg_write(ohci, OHCI1394_IsoXmitIntEventClear, 0xffffffff);

	/* Accept asynchronous transfer requests from all nodes for now */
	reg_write(ohci, OHCI1394_AsReqFilterHiSet, 0x80000000);

	/* Specify asynchronous transfer retries */
	reg_write(ohci, OHCI1394_ATRetries,
	OHCI1394_MAX_AT_REQ_RETRIES \|
	(OHCI1394_MAX_AT_RESP_RETRIES<<4) \|
	(OHCI1394_MAX_PHYS_RESP_RETRIES<<8));

	/* We don't want hardware swapping */
	reg_write(ohci, OHCI1394_HCControlClear,
	OHCI1394_HCControl_noByteSwapData);

	/* Enable link */
	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_linkEnable);

	/* If anything is connected to a port, make sure it is enabled */
	num_ports = get_phy_reg(ohci, 2) & 0xf;
	for (i = 0; i < num_ports; i++) {
	unsigned int status;

	set_phy_reg(ohci, 7, i);
	status = get_phy_reg(ohci, 8);

	if (status & 0x20)
	set_phy_reg(ohci, 8, status & ~1);
	}
	}

	/**
	* init_ohci1394_wait_for_busresets - wait until bus resets are completed
	*
	* OHCI1394 initialization itself and any device going on- or offline
	* and any cable issue cause a IEEE1394 bus reset. The OHCI1394 spec
	* specifies that physical DMA is disabled on each bus reset and it
	* has to be enabled after each bus reset when needed. We resort
	* to polling here because on early boot, we have no interrupts.
	*/
	static inline void __init init_ohci1394_wait_for_busresets(struct ohci *ohci)
	{
	int i, events;

	for (i = 0; i < 9; i++) {
	mdelay(200);
	events = reg_read(ohci, OHCI1394_IntEventSet);
	if (events & OHCI1394_busReset)
	reg_write(ohci, OHCI1394_IntEventClear,
	OHCI1394_busReset);
	}
	}

	/**
	* init_ohci1394_enable_physical_dma - Enable physical DMA for remote debugging
	* This enables remote DMA access over IEEE1394 from every host for the low
	* 4GB of address space. DMA accesses above 4GB are not available currently.
	*/
	static inline void __init init_ohci1394_enable_physical_dma(struct ohci *ohci)
	{
	reg_write(ohci, OHCI1394_PhyReqFilterHiSet, 0xffffffff);
	reg_write(ohci, OHCI1394_PhyReqFilterLoSet, 0xffffffff);
	reg_write(ohci, OHCI1394_PhyUpperBound, 0xffff0000);
	}

	/**
	* init_ohci1394_reset_and_init_dma - init controller and enable DMA
	* This initializes the given controller and enables physical DMA engine in it.
	*/
	static inline void __init init_ohci1394_reset_and_init_dma(struct ohci *ohci)
	{
	/* Start off with a soft reset, clears everything to a sane state. */
	init_ohci1394_soft_reset(ohci);

	/* Accessing some registers without LPS enabled may cause lock up */
	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_LPS);

	/* Disable and clear interrupts */
	reg_write(ohci, OHCI1394_IntEventClear, 0xffffffff);
	reg_write(ohci, OHCI1394_IntMaskClear, 0xffffffff);

	mdelay(50); /* Wait 50msec to make sure we have full link enabled */

	init_ohci1394_initialize(ohci);
	/*
	* The initialization causes at least one IEEE1394 bus reset. Enabling
	* physical DMA only works after all bus resets have calmed down:
	*/
	init_ohci1394_wait_for_busresets(ohci);

	/* We had to wait and do this now if we want to debug early problems */
	init_ohci1394_enable_physical_dma(ohci);
	}

	/**
	* init_ohci1394_controller - Map the registers of the controller and init DMA
	* This maps the registers of the specified controller and initializes it
	*/
	static inline void __init init_ohci1394_controller(int num, int slot, int func)
	{
	unsigned long ohci_base;
	struct ohci ohci;

	printk(KERN_INFO "init_ohci1394_dma: initializing OHCI-1394"
	" at %02x:%02x.%x\n", num, slot, func);

	ohci_base = read_pci_config(num, slot, func, PCI_BASE_ADDRESS_0+(0<<2))
	& PCI_BASE_ADDRESS_MEM_MASK;

	set_fixmap_nocache(FIX_OHCI1394_BASE, ohci_base);

	ohci.registers = (void __iomem *)fix_to_virt(FIX_OHCI1394_BASE);

	init_ohci1394_reset_and_init_dma(&ohci);
	}

	/**
	* debug_init_ohci1394_dma - scan for OHCI1394 controllers and init DMA on them
	* Scans the whole PCI space for OHCI1394 controllers and inits DMA on them
	*/
	void __init init_ohci1394_dma_on_all_controllers(void)
	{
	int num, slot, func;
	u32 class;

	if (!early_pci_allowed())
	return;

	/* Poor man's PCI discovery, the only thing we can do at early boot */
	for (num = 0; num < 32; num++) {
	for (slot = 0; slot < 32; slot++) {
	for (func = 0; func < 8; func++) {
	class = read_pci_config(num, slot, func,
	PCI_CLASS_REVISION);
	if (class == 0xffffffff)
	continue; /* No device at this func */

	if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
	continue; /* Not an OHCI-1394 device */

	init_ohci1394_controller(num, slot, func);
	break; /* Assume one controller per device */
	}
	}
	}
	printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI DMA\n");
	}

	/**
	* setup_init_ohci1394_early - enables early OHCI1394 DMA initialization
	*/
	static int __init setup_ohci1394_dma(char *opt)
	{
	if (!strcmp(opt, "early"))
	init_ohci1394_dma_early = 1;
	return 0;
	}

	/* passing ohci1394_dma=early on boot causes early OHCI1394 DMA initialization */
	early_param("ohci1394_dma", setup_ohci1394_dma);