From 1ab2bc7fb6de19bcf4da83f4f0f384d93db48711 Mon Sep 17 00:00:00 2001
From: Michael Zoran <mzoran@crowfest.net>
Date: Sat, 14 Jan 2017 21:33:51 -0800
Subject: [PATCH] ARM64/DWC_OTG: Port dwc_otg driver to ARM64

In ARM64, the FIQ mechanism used by this driver is not current
implemented.   As a workaround, reqular IRQ is used instead
of FIQ.

In a separate change, the IRQ-CPU mapping is round robined
on ARM64 to increase concurrency and allow multiple interrupts
to be serviced at a time.  This reduces the need for FIQ.

Tests Run:

This mechanism is most likely to break when multiple USB devices
are attached at the same time.  So the system was tested under
stress.

Devices:

1. USB Speakers playing back a FLAC audio through VLC
   at 96KHz.(Higher then typically, but supported on my speakers).

2. sftp transferring large files through the buildin ethernet
   connection which is connected through USB.

3. Keyboard and mouse attached and being used.

Although I do occasionally hear some glitches, the music seems to
play quite well.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
---
 drivers/usb/host/dwc_otg/Makefile            |  3 +
 drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c   | 17 +++++
 drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h   | 24 +++++++
 drivers/usb/host/dwc_otg/dwc_otg_hcd.c       |  4 ++
 drivers/usb/host/dwc_otg/dwc_otg_hcd_if.h    |  4 ++
 drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c  |  3 +-
 drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c | 72 ++++++++++++++++++++
 drivers/usb/host/dwc_otg/dwc_otg_os_dep.h    |  2 +
 8 files changed, 128 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/dwc_otg/Makefile
+++ b/drivers/usb/host/dwc_otg/Makefile
@@ -37,7 +37,10 @@ dwc_otg-objs	+= dwc_otg_pcd_linux.o dwc_
 dwc_otg-objs	+= dwc_otg_hcd.o dwc_otg_hcd_linux.o dwc_otg_hcd_intr.o dwc_otg_hcd_queue.o dwc_otg_hcd_ddma.o
 dwc_otg-objs	+= dwc_otg_adp.o
 dwc_otg-objs	+= dwc_otg_fiq_fsm.o
+ifneq ($(CONFIG_ARM64),y)
 dwc_otg-objs	+= dwc_otg_fiq_stub.o
+endif
+
 ifneq ($(CFI),)
 dwc_otg-objs	+= dwc_otg_cfi.o
 endif
--- a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
@@ -74,6 +74,21 @@ void notrace _fiq_print(enum fiq_debug_l
 	}
 }
 
+
+#ifdef CONFIG_ARM64
+
+inline void fiq_fsm_spin_lock(fiq_lock_t *lock)
+{
+	spin_lock((spinlock_t *)lock);
+}
+
+inline void fiq_fsm_spin_unlock(fiq_lock_t *lock)
+{
+	spin_unlock((spinlock_t *)lock);
+}
+
+#else
+
 /**
  * fiq_fsm_spin_lock() - ARMv6+ bare bones spinlock
  * Must be called with local interrupts and FIQ disabled.
@@ -121,6 +136,8 @@ inline void fiq_fsm_spin_unlock(fiq_lock
 inline void fiq_fsm_spin_unlock(fiq_lock_t *lock) { }
 #endif
 
+#endif
+
 /**
  * fiq_fsm_restart_channel() - Poke channel enable bit for a split transaction
  * @channel: channel to re-enable
--- a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
+++ b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
@@ -127,6 +127,12 @@ enum fiq_debug_level {
 	FIQDBG_PORTHUB = (1 << 3),
 };
 
+#ifdef CONFIG_ARM64
+
+typedef spinlock_t fiq_lock_t;
+
+#else
+
 typedef struct {
 	union {
 		uint32_t slock;
@@ -137,6 +143,8 @@ typedef struct {
 	};
 } fiq_lock_t;
 
+#endif
+
 struct fiq_state;
 
 extern void _fiq_print (enum fiq_debug_level dbg_lvl, volatile struct fiq_state *state, char *fmt, ...);
@@ -357,6 +365,22 @@ struct fiq_state {
 	struct fiq_channel_state channel[0];
 };
 
+#ifdef CONFIG_ARM64
+
+#ifdef local_fiq_enable
+#undef local_fiq_enable
+#endif
+
+#ifdef local_fiq_disable
+#undef local_fiq_disable
+#endif
+
+extern void local_fiq_enable(void);
+
+extern void local_fiq_disable(void);
+
+#endif
+
 extern void fiq_fsm_spin_lock(fiq_lock_t *lock);
 
 extern void fiq_fsm_spin_unlock(fiq_lock_t *lock);
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
@@ -1014,6 +1014,10 @@ int dwc_otg_hcd_init(dwc_otg_hcd_t * hcd
 		}
 		DWC_MEMSET(hcd->fiq_state, 0, (sizeof(struct fiq_state) + (sizeof(struct fiq_channel_state) * num_channels)));
 
+#ifdef CONFIG_ARM64
+		spin_lock_init(&hcd->fiq_state->lock);
+#endif
+
 		for (i = 0; i < num_channels; i++) {
 			hcd->fiq_state->channel[i].fsm = FIQ_PASSTHROUGH;
 		}
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_if.h
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_if.h
@@ -116,7 +116,11 @@ extern int32_t dwc_otg_hcd_handle_intr(d
 /** This function is used to handle the fast interrupt
  *
  */
+#ifdef CONFIG_ARM64
+extern void dwc_otg_hcd_handle_fiq(void);
+#else
 extern void __attribute__ ((naked)) dwc_otg_hcd_handle_fiq(void);
+#endif
 
 /**
  * Returns private data set by
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c
@@ -36,8 +36,9 @@
 #include "dwc_otg_regs.h"
 
 #include <linux/jiffies.h>
+#ifdef CONFIG_ARM
 #include <asm/fiq.h>
-
+#endif
 
 extern bool microframe_schedule;
 
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c
@@ -51,7 +51,9 @@
 #include <linux/dma-mapping.h>
 #include <linux/version.h>
 #include <asm/io.h>
+#ifdef CONFIG_ARM
 #include <asm/fiq.h>
+#endif
 #include <linux/usb.h>
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)
 #include <../drivers/usb/core/hcd.h>
@@ -71,6 +73,13 @@
 #include "dwc_otg_driver.h"
 #include "dwc_otg_hcd.h"
 
+#ifndef __virt_to_bus
+#define __virt_to_bus	__virt_to_phys
+#define __bus_to_virt	__phys_to_virt
+#define __pfn_to_bus(x)	__pfn_to_phys(x)
+#define __bus_to_pfn(x)	__phys_to_pfn(x)
+#endif
+
 extern unsigned char  _dwc_otg_fiq_stub, _dwc_otg_fiq_stub_end;
 
 /**
@@ -395,14 +404,49 @@ static struct dwc_otg_hcd_function_ops h
 	.get_b_hnp_enable = _get_b_hnp_enable,
 };
 
+#ifdef CONFIG_ARM64
+
+static int simfiq_irq = -1;
+
+void local_fiq_enable(void)
+{
+	if (simfiq_irq >= 0)
+		enable_irq(simfiq_irq);
+}
+
+void local_fiq_disable(void)
+{
+	if (simfiq_irq >= 0)
+		disable_irq(simfiq_irq);
+}
+
+irqreturn_t fiq_irq_handler(int irq, void *dev_id)
+{
+	dwc_otg_hcd_t *dwc_otg_hcd = (dwc_otg_hcd_t *)dev_id;
+
+	if (fiq_fsm_enable)
+		dwc_otg_fiq_fsm(dwc_otg_hcd->fiq_state, dwc_otg_hcd->core_if->core_params->host_channels);
+	else
+		dwc_otg_fiq_nop(dwc_otg_hcd->fiq_state);
+
+	return IRQ_HANDLED;
+}
+
+#else
 static struct fiq_handler fh = {
   .name = "usb_fiq",
 };
 
+#endif
+
 static void hcd_init_fiq(void *cookie)
 {
 	dwc_otg_device_t *otg_dev = cookie;
 	dwc_otg_hcd_t *dwc_otg_hcd = otg_dev->hcd;
+#ifdef CONFIG_ARM64
+	int retval = 0;
+	int irq;
+#else
 	struct pt_regs regs;
 	int irq;
 
@@ -430,6 +474,7 @@ static void hcd_init_fiq(void *cookie)
 
 //		__show_regs(&regs);
 	set_fiq_regs(&regs);
+#endif
 
 	//Set the mphi periph to  the required registers
 	dwc_otg_hcd->fiq_state->mphi_regs.base    = otg_dev->os_dep.mphi_base;
@@ -448,6 +493,23 @@ static void hcd_init_fiq(void *cookie)
 		DWC_WARN("MPHI periph has NOT been enabled");
 #endif
 	// Enable FIQ interrupt from USB peripheral
+#ifdef CONFIG_ARM64
+	irq = platform_get_irq(otg_dev->os_dep.platformdev, 1);
+
+	if (irq < 0) {
+		DWC_ERROR("Can't get SIM-FIQ irq");
+		return;
+	}
+
+	retval = request_irq(irq, fiq_irq_handler, 0, "dwc_otg_sim-fiq", dwc_otg_hcd);
+
+	if (retval < 0) {
+		DWC_ERROR("Unable to request SIM-FIQ irq\n");
+		return;
+	}
+
+	simfiq_irq = irq;
+#else
 #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
 	irq = platform_get_irq(otg_dev->os_dep.platformdev, 1);
 #else
@@ -464,6 +526,8 @@ static void hcd_init_fiq(void *cookie)
 	smp_mb();
 	enable_fiq(irq);
 	local_fiq_enable();
+#endif
+
 }
 
 /**
@@ -526,6 +590,13 @@ int hcd_init(dwc_bus_dev_t *_dev)
 	otg_dev->hcd = dwc_otg_hcd;
 	otg_dev->hcd->otg_dev = otg_dev;
 
+#ifdef CONFIG_ARM64
+	if (dwc_otg_hcd_init(dwc_otg_hcd, otg_dev->core_if))
+		goto error2;
+
+	if (fiq_enable)
+		hcd_init_fiq(otg_dev);
+#else
 	if (dwc_otg_hcd_init(dwc_otg_hcd, otg_dev->core_if)) {
 		goto error2;
 	}
@@ -542,6 +613,7 @@ int hcd_init(dwc_bus_dev_t *_dev)
 			smp_call_function_single(0, hcd_init_fiq, otg_dev, 1);
 		}
 	}
+#endif
 
 	hcd->self.otg_port = dwc_otg_hcd_otg_port(dwc_otg_hcd);
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,33) //don't support for LM(with 2.6.20.1 kernel)
--- a/drivers/usb/host/dwc_otg/dwc_otg_os_dep.h
+++ b/drivers/usb/host/dwc_otg/dwc_otg_os_dep.h
@@ -76,8 +76,10 @@
 
 #ifdef PLATFORM_INTERFACE
 #include <linux/platform_device.h>
+#ifdef CONFIG_ARM
 #include <asm/mach/map.h>
 #endif
+#endif
 
 /** The OS page size */
 #define DWC_OS_PAGE_SIZE	PAGE_SIZE
