1 files changed, 296 insertions, 0 deletions
diff --git a/drivers/firewire/init_ohci1394_dma.c b/drivers/firewire/init_ohci1394_dma.c
new file mode 100644
index 0000000000..48b879e9e8
--- /dev/null
+++ b/drivers/firewire/init_ohci1394_dma.c
@@ -0,0 +1,296 @@
+// 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);
+}
+
+/**
+ * init_ohci1394_dma_on_all_controllers - 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_ohci1394_dma - 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);