Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

Pull arch/tile updates from Chris Metcalf:
 "The only substantive pieces in this batch are some more vDSO support,
  and removing the reference to &platform_bus in tile-srom.c.

  The rest are minor issues reported to me"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: add clock_gettime support to vDSO
  tile: switch to using seqlocks for the vDSO time code
  tile gxio: use better string copy primitive
  char: tile-srom: Add real platform bus parent
  Removed repeated word in comments
  tilegx: Enable ARCH_SUPPORTS_ATOMIC_RMW
  tile: Remove tile-specific _sinitdata and _einitdata
  tile: use ARRAY_SIZE

12 files changed, 245 insertions, 94 deletions

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 7fcd492adbfc..7cca41842a9e 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -134,6 +134,7 @@ config TILEGX
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
 	select HAVE_ARCH_KGDB
+	select ARCH_SUPPORTS_ATOMIC_RMW
 
 config TILEPRO
 	def_bool !TILEGX
diff --git a/arch/tile/gxio/mpipe.c b/arch/tile/gxio/mpipe.c
index 5301a9ffbae1..320ff5e6e61e 100644
--- a/arch/tile/gxio/mpipe.c
+++ b/arch/tile/gxio/mpipe.c
@@ -29,6 +29,32 @@
 /* HACK: Avoid pointless "shadow" warnings. */
 #define link link_shadow
 
+/**
+ * strscpy - Copy a C-string into a sized buffer, but only if it fits
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @size: size of destination buffer
+ *
+ * Use this routine to avoid copying too-long strings.
+ * The routine returns the total number of bytes copied
+ * (including the trailing NUL) or zero if the buffer wasn't
+ * big enough.  To ensure that programmers pay attention
+ * to the return code, the destination has a single NUL
+ * written at the front (if size is non-zero) when the
+ * buffer is not big enough.
+ */
+static size_t strscpy(char *dest, const char *src, size_t size)
+{
+	size_t len = strnlen(src, size) + 1;
+	if (len > size) {
+		if (size)
+			dest[0] = '\0';
+		return 0;
+	}
+	memcpy(dest, src, len);
+	return len;
+}
+
 int gxio_mpipe_init(gxio_mpipe_context_t *context, unsigned int mpipe_index)
 {
 	char file[32];
@@ -511,8 +537,8 @@ int gxio_mpipe_link_instance(const char *link_name)
 	if (!context)
 		return GXIO_ERR_NO_DEVICE;
 
-	strncpy(name.name, link_name, sizeof(name.name));
-	name.name[GXIO_MPIPE_LINK_NAME_LEN - 1] = '\0';
+	if (strscpy(name.name, link_name, sizeof(name.name)) == 0)
+		return GXIO_ERR_NO_DEVICE;
 
 	return gxio_mpipe_info_instance_aux(context, name);
 }
@@ -529,7 +555,8 @@ int gxio_mpipe_link_enumerate_mac(int idx, char *link_name, uint8_t *link_mac)
 
 	rv = gxio_mpipe_info_enumerate_aux(context, idx, &name, &mac);
 	if (rv >= 0) {
-		strncpy(link_name, name.name, sizeof(name.name));
+		if (strscpy(link_name, name.name, sizeof(name.name)) == 0)
+			return GXIO_ERR_INVAL_MEMORY_SIZE;
 		memcpy(link_mac, mac.mac, sizeof(mac.mac));
 	}
 
@@ -545,8 +572,8 @@ int gxio_mpipe_link_open(gxio_mpipe_link_t *link,
 	_gxio_mpipe_link_name_t name;
 	int rv;
 
-	strncpy(name.name, link_name, sizeof(name.name));
-	name.name[GXIO_MPIPE_LINK_NAME_LEN - 1] = '\0';
+	if (strscpy(name.name, link_name, sizeof(name.name)) == 0)
+		return GXIO_ERR_NO_DEVICE;
 
 	rv = gxio_mpipe_link_open_aux(context, name, flags);
 	if (rv < 0)
diff --git a/arch/tile/include/asm/sections.h b/arch/tile/include/asm/sections.h
index 5d5d3b739a6b..86a746243dc8 100644
--- a/arch/tile/include/asm/sections.h
+++ b/arch/tile/include/asm/sections.h
@@ -19,9 +19,6 @@
 
 #include <asm-generic/sections.h>
 
-/* Text and data are at different areas in the kernel VA space. */
-extern char _sinitdata[], _einitdata[];
-
 /* Write-once data is writable only till the end of initialization. */
 extern char __w1data_begin[], __w1data_end[];
 
diff --git a/arch/tile/include/asm/vdso.h b/arch/tile/include/asm/vdso.h
index 9f6a78d665fa..9b069692153f 100644
--- a/arch/tile/include/asm/vdso.h
+++ b/arch/tile/include/asm/vdso.h
@@ -15,6 +15,7 @@
 #ifndef __TILE_VDSO_H__
 #define __TILE_VDSO_H__
 
+#include <linux/seqlock.h>
 #include <linux/types.h>
 
 /*
@@ -26,15 +27,20 @@
  */
 
 struct vdso_data {
-	__u64 tz_update_count;  /* Timezone atomicity ctr             */
-	__u64 tb_update_count;  /* Timebase atomicity ctr             */
-	__u64 xtime_tod_stamp;  /* TOD clock for xtime                */
-	__u64 xtime_clock_sec;  /* Kernel time second                 */
-	__u64 xtime_clock_nsec; /* Kernel time nanosecond             */
-	__u64 wtom_clock_sec;   /* Wall to monotonic clock second     */
-	__u64 wtom_clock_nsec;  /* Wall to monotonic clock nanosecond */
+	seqcount_t tz_seq;	/* Timezone seqlock                   */
+	seqcount_t tb_seq;	/* Timebase seqlock                   */
+	__u64 cycle_last;       /* TOD clock for xtime                */
+	__u64 mask;             /* Cycle mask                         */
 	__u32 mult;             /* Cycle to nanosecond multiplier     */
 	__u32 shift;            /* Cycle to nanosecond divisor (power of two) */
+	__u64 wall_time_sec;
+	__u64 wall_time_snsec;
+	__u64 monotonic_time_sec;
+	__u64 monotonic_time_snsec;
+	__u64 wall_time_coarse_sec;
+	__u64 wall_time_coarse_nsec;
+	__u64 monotonic_time_coarse_sec;
+	__u64 monotonic_time_coarse_nsec;
 	__u32 tz_minuteswest;   /* Minutes west of Greenwich          */
 	__u32 tz_dsttime;       /* Type of dst correction             */
 };
diff --git a/arch/tile/include/uapi/arch/sim_def.h b/arch/tile/include/uapi/arch/sim_def.h
index 4b44a2b6a09a..1c069537ae41 100644
--- a/arch/tile/include/uapi/arch/sim_def.h
+++ b/arch/tile/include/uapi/arch/sim_def.h
@@ -360,19 +360,19 @@
  * @{
  */
 
-/** Use with with SIM_PROFILER_CHIP_xxx to control the memory controllers. */
+/** Use with SIM_PROFILER_CHIP_xxx to control the memory controllers. */
 #define SIM_CHIP_MEMCTL        0x001
 
-/** Use with with SIM_PROFILER_CHIP_xxx to control the XAUI interface. */
+/** Use with SIM_PROFILER_CHIP_xxx to control the XAUI interface. */
 #define SIM_CHIP_XAUI          0x002
 
-/** Use with with SIM_PROFILER_CHIP_xxx to control the PCIe interface. */
+/** Use with SIM_PROFILER_CHIP_xxx to control the PCIe interface. */
 #define SIM_CHIP_PCIE          0x004
 
-/** Use with with SIM_PROFILER_CHIP_xxx to control the MPIPE interface. */
+/** Use with SIM_PROFILER_CHIP_xxx to control the MPIPE interface. */
 #define SIM_CHIP_MPIPE         0x008
 
-/** Use with with SIM_PROFILER_CHIP_xxx to control the TRIO interface. */
+/** Use with SIM_PROFILER_CHIP_xxx to control the TRIO interface. */
 #define SIM_CHIP_TRIO          0x010
 
 /** Reference all chip devices. */
diff --git a/arch/tile/kernel/time.c b/arch/tile/kernel/time.c
index d8fbc289e680..c1b362277fb7 100644
--- a/arch/tile/kernel/time.c
+++ b/arch/tile/kernel/time.c
@@ -249,33 +249,52 @@ cycles_t ns2cycles(unsigned long nsecs)
 
 void update_vsyscall_tz(void)
 {
-	/* Userspace gettimeofday will spin while this value is odd. */
-	++vdso_data->tz_update_count;
-	smp_wmb();
+	write_seqcount_begin(&vdso_data->tz_seq);
 	vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
 	vdso_data->tz_dsttime = sys_tz.tz_dsttime;
-	smp_wmb();
-	++vdso_data->tz_update_count;
+	write_seqcount_end(&vdso_data->tz_seq);
 }
 
 void update_vsyscall(struct timekeeper *tk)
 {
-	struct timespec *wtm = &tk->wall_to_monotonic;
-	struct clocksource *clock = tk->tkr.clock;
-
-	if (clock != &cycle_counter_cs)
+	if (tk->tkr.clock != &cycle_counter_cs)
 		return;
 
-	/* Userspace gettimeofday will spin while this value is odd. */
-	++vdso_data->tb_update_count;
-	smp_wmb();
-	vdso_data->xtime_tod_stamp = tk->tkr.cycle_last;
-	vdso_data->xtime_clock_sec = tk->xtime_sec;
-	vdso_data->xtime_clock_nsec = tk->tkr.xtime_nsec;
-	vdso_data->wtom_clock_sec = wtm->tv_sec;
-	vdso_data->wtom_clock_nsec = wtm->tv_nsec;
-	vdso_data->mult = tk->tkr.mult;
-	vdso_data->shift = tk->tkr.shift;
-	smp_wmb();
-	++vdso_data->tb_update_count;
+	write_seqcount_begin(&vdso_data->tb_seq);
+
+	vdso_data->cycle_last		= tk->tkr.cycle_last;
+	vdso_data->mask			= tk->tkr.mask;
+	vdso_data->mult			= tk->tkr.mult;
+	vdso_data->shift		= tk->tkr.shift;
+
+	vdso_data->wall_time_sec	= tk->xtime_sec;
+	vdso_data->wall_time_snsec	= tk->tkr.xtime_nsec;
+
+	vdso_data->monotonic_time_sec	= tk->xtime_sec
+					+ tk->wall_to_monotonic.tv_sec;
+	vdso_data->monotonic_time_snsec	= tk->tkr.xtime_nsec
+					+ ((u64)tk->wall_to_monotonic.tv_nsec
+						<< tk->tkr.shift);
+	while (vdso_data->monotonic_time_snsec >=
+					(((u64)NSEC_PER_SEC) << tk->tkr.shift)) {
+		vdso_data->monotonic_time_snsec -=
+					((u64)NSEC_PER_SEC) << tk->tkr.shift;
+		vdso_data->monotonic_time_sec++;
+	}
+
+	vdso_data->wall_time_coarse_sec	= tk->xtime_sec;
+	vdso_data->wall_time_coarse_nsec = (long)(tk->tkr.xtime_nsec >>
+						 tk->tkr.shift);
+
+	vdso_data->monotonic_time_coarse_sec =
+		vdso_data->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec;
+	vdso_data->monotonic_time_coarse_nsec =
+		vdso_data->wall_time_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
+
+	while (vdso_data->monotonic_time_coarse_nsec >= NSEC_PER_SEC) {
+		vdso_data->monotonic_time_coarse_nsec -= NSEC_PER_SEC;
+		vdso_data->monotonic_time_coarse_sec++;
+	}
+
+	write_seqcount_end(&vdso_data->tb_seq);
 }
diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index f3ceb6308e42..86900ccd4977 100644
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -277,7 +277,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 		if (fixup_exception(regs))  /* ILL_TRANS or UNALIGN_DATA */
 			return;
 		if (fault_num >= 0 &&
-		    fault_num < sizeof(int_name)/sizeof(int_name[0]) &&
+		    fault_num < ARRAY_SIZE(int_name) &&
 		    int_name[fault_num] != NULL)
 			name = int_name[fault_num];
 		else
diff --git a/arch/tile/kernel/vdso/vdso.lds.S b/arch/tile/kernel/vdso/vdso.lds.S
index 041cd6c39c83..731529f3f06f 100644
--- a/arch/tile/kernel/vdso/vdso.lds.S
+++ b/arch/tile/kernel/vdso/vdso.lds.S
@@ -82,6 +82,8 @@ VERSION
 		__vdso_rt_sigreturn;
 		__vdso_gettimeofday;
 		gettimeofday;
+		__vdso_clock_gettime;
+		clock_gettime;
 	local:*;
 	};
 }
diff --git a/arch/tile/kernel/vdso/vgettimeofday.c b/arch/tile/kernel/vdso/vgettimeofday.c
index e933fb9fbf5c..8bb21eda07d8 100644
--- a/arch/tile/kernel/vdso/vgettimeofday.c
+++ b/arch/tile/kernel/vdso/vgettimeofday.c
@@ -15,6 +15,7 @@
 #define VDSO_BUILD  /* avoid some shift warnings for -m32 in <asm/page.h> */
 #include <linux/time.h>
 #include <asm/timex.h>
+#include <asm/unistd.h>
 #include <asm/vdso.h>
 
 #if CHIP_HAS_SPLIT_CYCLE()
@@ -35,6 +36,11 @@ static inline cycles_t get_cycles_inline(void)
 #define get_cycles get_cycles_inline
 #endif
 
+struct syscall_return_value {
+	long value;
+	long error;
+};
+
 /*
  * Find out the vDSO data page address in the process address space.
  */
@@ -50,59 +56,143 @@ inline unsigned long get_datapage(void)
 	return ret;
 }
 
-int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
+static inline u64 vgetsns(struct vdso_data *vdso)
+{
+	return ((get_cycles() - vdso->cycle_last) & vdso->mask) * vdso->mult;
+}
+
+static inline int do_realtime(struct vdso_data *vdso, struct timespec *ts)
+{
+	unsigned count;
+	u64 ns;
+
+	do {
+		count = read_seqcount_begin(&vdso->tb_seq);
+		ts->tv_sec = vdso->wall_time_sec;
+		ns = vdso->wall_time_snsec;
+		ns += vgetsns(vdso);
+		ns >>= vdso->shift;
+	} while (unlikely(read_seqcount_retry(&vdso->tb_seq, count)));
+
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
+
+	return 0;
+}
+
+static inline int do_monotonic(struct vdso_data *vdso, struct timespec *ts)
+{
+	unsigned count;
+	u64 ns;
+
+	do {
+		count = read_seqcount_begin(&vdso->tb_seq);
+		ts->tv_sec = vdso->monotonic_time_sec;
+		ns = vdso->monotonic_time_snsec;
+		ns += vgetsns(vdso);
+		ns >>= vdso->shift;
+	} while (unlikely(read_seqcount_retry(&vdso->tb_seq, count)));
+
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
+
+	return 0;
+}
+
+static inline int do_realtime_coarse(struct vdso_data *vdso,
+				     struct timespec *ts)
+{
+	unsigned count;
+
+	do {
+		count = read_seqcount_begin(&vdso->tb_seq);
+		ts->tv_sec = vdso->wall_time_coarse_sec;
+		ts->tv_nsec = vdso->wall_time_coarse_nsec;
+	} while (unlikely(read_seqcount_retry(&vdso->tb_seq, count)));
+
+	return 0;
+}
+
+static inline int do_monotonic_coarse(struct vdso_data *vdso,
+				      struct timespec *ts)
 {
-	cycles_t cycles;
-	unsigned long count, sec, ns;
-	volatile struct vdso_data *vdso_data;
+	unsigned count;
+
+	do {
+		count = read_seqcount_begin(&vdso->tb_seq);
+		ts->tv_sec = vdso->monotonic_time_coarse_sec;
+		ts->tv_nsec = vdso->monotonic_time_coarse_nsec;
+	} while (unlikely(read_seqcount_retry(&vdso->tb_seq, count)));
+
+	return 0;
+}
+
+struct syscall_return_value __vdso_gettimeofday(struct timeval *tv,
+						struct timezone *tz)
+{
+	struct syscall_return_value ret = { 0, 0 };
+	unsigned count;
+	struct vdso_data *vdso = (struct vdso_data *)get_datapage();
 
-	vdso_data = (struct vdso_data *)get_datapage();
 	/* The use of the timezone is obsolete, normally tz is NULL. */
 	if (unlikely(tz != NULL)) {
-		while (1) {
-			/* Spin until the update finish. */
-			count = vdso_data->tz_update_count;
-			if (count & 1)
-				continue;
-
-			tz->tz_minuteswest = vdso_data->tz_minuteswest;
-			tz->tz_dsttime = vdso_data->tz_dsttime;
-
-			/* Check whether updated, read again if so. */
-			if (count == vdso_data->tz_update_count)
-				break;
-		}
+		do {
+			count = read_seqcount_begin(&vdso->tz_seq);
+			tz->tz_minuteswest = vdso->tz_minuteswest;
+			tz->tz_dsttime = vdso->tz_dsttime;
+		} while (unlikely(read_seqcount_retry(&vdso->tz_seq, count)));
 	}
 
 	if (unlikely(tv == NULL))
-		return 0;
-
-	while (1) {
-		/* Spin until the update finish. */
-		count = vdso_data->tb_update_count;
-		if (count & 1)
-			continue;
-
-		sec = vdso_data->xtime_clock_sec;
-		cycles = get_cycles() - vdso_data->xtime_tod_stamp;
-		ns = (cycles * vdso_data->mult) + vdso_data->xtime_clock_nsec;
-		ns >>= vdso_data->shift;
-
-		if (ns >= NSEC_PER_SEC) {
-			ns -= NSEC_PER_SEC;
-			sec += 1;
-		}
-
-		/* Check whether updated, read again if so. */
-		if (count == vdso_data->tb_update_count)
-			break;
-	}
+		return ret;
 
-	tv->tv_sec = sec;
-	tv->tv_usec = ns / 1000;
+	do_realtime(vdso, (struct timespec *)tv);
+	tv->tv_usec /= 1000;
 
-	return 0;
+	return ret;
 }
 
 int gettimeofday(struct timeval *tv, struct timezone *tz)
 	__attribute__((weak, alias("__vdso_gettimeofday")));
+
+static struct syscall_return_value vdso_fallback_gettime(long clock,
+							 struct timespec *ts)
+{
+	struct syscall_return_value ret;
+	__asm__ __volatile__ (
+		"swint1"
+		: "=R00" (ret.value), "=R01" (ret.error)
+		: "R10" (__NR_clock_gettime), "R00" (clock), "R01" (ts)
+		: "r2", "r3", "r4", "r5", "r6", "r7",
+		"r8",  "r9", "r11", "r12", "r13", "r14", "r15",
+		"r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
+		"r24", "r25", "r26", "r27", "r28", "r29", "memory");
+	return ret;
+}
+
+struct syscall_return_value __vdso_clock_gettime(clockid_t clock,
+						 struct timespec *ts)
+{
+	struct vdso_data *vdso = (struct vdso_data *)get_datapage();
+	struct syscall_return_value ret = { 0, 0 };
+
+	switch (clock) {
+	case CLOCK_REALTIME:
+		do_realtime(vdso, ts);
+		return ret;
+	case CLOCK_MONOTONIC:
+		do_monotonic(vdso, ts);
+		return ret;
+	case CLOCK_REALTIME_COARSE:
+		do_realtime_coarse(vdso, ts);
+		return ret;
+	case CLOCK_MONOTONIC_COARSE:
+		do_monotonic_coarse(vdso, ts);
+		return ret;
+	default:
+		return vdso_fallback_gettime(clock, ts);
+	}
+}
+
+int clock_gettime(clockid_t clock, struct timespec *ts)
+	__attribute__((weak, alias("__vdso_clock_gettime")));
diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S
index f1819423ffc9..0e059a0101ea 100644
--- a/arch/tile/kernel/vmlinux.lds.S
+++ b/arch/tile/kernel/vmlinux.lds.S
@@ -66,11 +66,9 @@ SECTIONS
 
   . = ALIGN(PAGE_SIZE);
   __init_begin = .;
-  VMLINUX_SYMBOL(_sinitdata) = .;
   INIT_DATA_SECTION(16) :data =0
   PERCPU_SECTION(L2_CACHE_BYTES)
   . = ALIGN(PAGE_SIZE);
-  VMLINUX_SYMBOL(_einitdata) = .;
   __init_end = .;
 
   _sdata = .;                   /* Start of data section */
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index bfb3127b4df9..a092e393bd20 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -254,8 +254,8 @@ static pgprot_t __init init_pgprot(ulong address)
 	 * Everything else that isn't data or bss is heap, so mark it
 	 * with the initial heap home (hash-for-home, or this cpu).  This
 	 * includes any addresses after the loaded image and any address before
-	 * _einitdata, since we already captured the case of text before
-	 * _sinittext, and __pa(einittext) is approximately __pa(sinitdata).
+	 * __init_end, since we already captured the case of text before
+	 * _sinittext, and __pa(einittext) is approximately __pa(__init_begin).
 	 *
 	 * All the LOWMEM pages that we mark this way will get their
 	 * struct page homecache properly marked later, in set_page_homes().
@@ -263,7 +263,7 @@ static pgprot_t __init init_pgprot(ulong address)
 	 * homes, but with a zero free_time we don't have to actually
 	 * do a flush action the first time we use them, either.
 	 */
-	if (address >= (ulong) _end || address < (ulong) _einitdata)
+	if (address >= (ulong) _end || address < (ulong) __init_end)
 		return construct_pgprot(PAGE_KERNEL, initial_heap_home());
 
 	/* Use hash-for-home if requested for data/bss. */
@@ -632,7 +632,7 @@ int devmem_is_allowed(unsigned long pagenr)
 {
 	return pagenr < kaddr_to_pfn(_end) &&
 		!(pagenr >= kaddr_to_pfn(&init_thread_union) ||
-		  pagenr < kaddr_to_pfn(_einitdata)) &&
+		  pagenr < kaddr_to_pfn(__init_end)) &&
 		!(pagenr >= kaddr_to_pfn(_sinittext) ||
 		  pagenr <= kaddr_to_pfn(_einittext-1));
 }
@@ -975,8 +975,8 @@ void free_initmem(void)
 
 	/* Free the data pages that we won't use again after init. */
 	free_init_pages("unused kernel data",
-			(unsigned long)_sinitdata,
-			(unsigned long)_einitdata);
+			(unsigned long)__init_begin,
+			(unsigned long)__init_end);
 
 	/*
 	 * Free the pages mapped from 0xc0000000 that correspond to code
diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
index bd377472dcfb..02e76ac6d282 100644
--- a/drivers/char/tile-srom.c
+++ b/drivers/char/tile-srom.c
@@ -76,6 +76,7 @@ MODULE_LICENSE("GPL");
 
 static int srom_devs;			/* Number of SROM partitions */
 static struct cdev srom_cdev;
+static struct platform_device *srom_parent;
 static struct class *srom_class;
 static struct srom_dev *srom_devices;
 
@@ -350,7 +351,7 @@ static int srom_setup_minor(struct srom_dev *srom, int index)
 		       SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
 		return -EIO;
 
-	dev = device_create(srom_class, &platform_bus,
+	dev = device_create(srom_class, &srom_parent->dev,
 			    MKDEV(srom_major, index), srom, "%d", index);
 	return PTR_ERR_OR_ZERO(dev);
 }
@@ -415,6 +416,13 @@ static int srom_init(void)
 	if (result < 0)
 		goto fail_chrdev;
 
+	/* Create a parent device */
+	srom_parent = platform_device_register_simple("srom", -1, NULL, 0);
+	if (IS_ERR(srom_parent)) {
+		result = PTR_ERR(srom_parent);
+		goto fail_pdev;
+	}
+
 	/* Create a sysfs class. */
 	srom_class = class_create(THIS_MODULE, "srom");
 	if (IS_ERR(srom_class)) {
@@ -438,6 +446,8 @@ fail_class:
 		device_destroy(srom_class, MKDEV(srom_major, i));
 	class_destroy(srom_class);
 fail_cdev:
+	platform_device_unregister(srom_parent);
+fail_pdev:
 	cdev_del(&srom_cdev);
 fail_chrdev:
 	unregister_chrdev_region(dev, srom_devs);
@@ -454,6 +464,7 @@ static void srom_cleanup(void)
 		device_destroy(srom_class, MKDEV(srom_major, i));
 	class_destroy(srom_class);
 	cdev_del(&srom_cdev);
+	platform_device_unregister(srom_parent);
 	unregister_chrdev_region(MKDEV(srom_major, 0), srom_devs);
 	kfree(srom_devices);
 }