Commit 7ae0e06b authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'arc-v3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC changes from Vineet Gupta:
 - IPI optimization and cleanups
 - Support for bootloader provided external Device Tree blobs

* tag 'arc-v3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: [cmdline] support External Device Trees from u-boot
  ARC: [cmdline] uboot cmdline handling rework
  ARC: [SMP] optimize IPI send and receive
  ARC: [SMP] simplify IPI code
  ARC: [SMP] cpu halt interface doesn't need "self" cpu-id
  ARC: [SMP] IPI ACK interface doesn't need "self" cpu-id
  ARC: [SMP] cpumask not needed in IPI send path
parents 9b83d851 e57d339a
...@@ -409,17 +409,6 @@ config ARC_DBG_TLB_MISS_COUNT ...@@ -409,17 +409,6 @@ config ARC_DBG_TLB_MISS_COUNT
Counts number of I and D TLB Misses and exports them via Debugfs Counts number of I and D TLB Misses and exports them via Debugfs
The counters can be cleared via Debugfs as well The counters can be cleared via Debugfs as well
config CMDLINE_UBOOT
bool "Support U-boot kernel command line passing"
default n
help
If you are using U-boot (www.denx.de) and wish to pass the kernel
command line from the U-boot environment to the Linux kernel then
switch this option on.
ARC U-boot will setup the cmdline in RAM/flash and set r2 to point
to it. kernel startup code will append this to DeviceTree
/bootargs provided cmdline args.
config ARC_BUILTIN_DTB_NAME config ARC_BUILTIN_DTB_NAME
string "Built in DTB" string "Built in DTB"
help help
......
...@@ -46,14 +46,14 @@ extern int smp_ipi_irq_setup(int cpu, int irq); ...@@ -46,14 +46,14 @@ extern int smp_ipi_irq_setup(int cpu, int irq);
* *
* @info: SoC SMP specific info for /proc/cpuinfo etc * @info: SoC SMP specific info for /proc/cpuinfo etc
* @cpu_kick: For Master to kickstart a cpu (optionally at a PC) * @cpu_kick: For Master to kickstart a cpu (optionally at a PC)
* @ipi_send: To send IPI to a @cpumask * @ipi_send: To send IPI to a @cpu
* @ips_clear: To clear IPI received by @cpu at @irq * @ips_clear: To clear IPI received at @irq
*/ */
struct plat_smp_ops { struct plat_smp_ops {
const char *info; const char *info;
void (*cpu_kick)(int cpu, unsigned long pc); void (*cpu_kick)(int cpu, unsigned long pc);
void (*ipi_send)(void *callmap); void (*ipi_send)(int cpu);
void (*ipi_clear)(int cpu, int irq); void (*ipi_clear)(int irq);
}; };
/* TBD: stop exporting it for direct population by platform */ /* TBD: stop exporting it for direct population by platform */
......
...@@ -49,25 +49,13 @@ stext: ...@@ -49,25 +49,13 @@ stext:
st.ab 0, [r5,4] st.ab 0, [r5,4]
brlt r5, r6, 1b brlt r5, r6, 1b
#ifdef CONFIG_CMDLINE_UBOOT ; Uboot - kernel ABI
; support for bootloader provided cmdline ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2
; If cmdline passed by u-boot, then ; r1 = magic number (board identity, unused as of now
; r0 = 1 (because ATAGS parsing, now retired, used to use 0) ; r2 = pointer to uboot provided cmdline or external DTB in mem
; r1 = magic number (board identity) ; These are handled later in setup_arch()
; r2 = addr of cmdline string (somewhere in memory/flash) st r0, [@uboot_tag]
st r2, [@uboot_arg]
brne r0, 1, .Lother_bootup_chores ; u-boot didn't pass cmdline
breq r2, 0, .Lother_bootup_chores ; or cmdline is NULL
mov r5, @command_line
1:
ldb.ab r6, [r2, 1]
breq r6, 0, .Lother_bootup_chores
b.d 1b
stb.ab r6, [r5, 1]
#endif
.Lother_bootup_chores:
; Identify if running on ISS vs Silicon ; Identify if running on ISS vs Silicon
; IDENTITY Reg [ 3 2 1 0 ] ; IDENTITY Reg [ 3 2 1 0 ]
......
...@@ -29,7 +29,10 @@ ...@@ -29,7 +29,10 @@
int running_on_hw = 1; /* vs. on ISS */ int running_on_hw = 1; /* vs. on ISS */
char __initdata command_line[COMMAND_LINE_SIZE]; /* Part of U-boot ABI: see head.S */
int __initdata uboot_tag;
char __initdata *uboot_arg;
const struct machine_desc *machine_desc; const struct machine_desc *machine_desc;
struct task_struct *_current_task[NR_CPUS]; /* For stack switching */ struct task_struct *_current_task[NR_CPUS]; /* For stack switching */
...@@ -311,19 +314,40 @@ void setup_processor(void) ...@@ -311,19 +314,40 @@ void setup_processor(void)
arc_chk_fpu(); arc_chk_fpu();
} }
static inline int is_kernel(unsigned long addr)
{
if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
return 1;
return 0;
}
void __init setup_arch(char **cmdline_p) void __init setup_arch(char **cmdline_p)
{ {
/* This also populates @boot_command_line from /bootargs */ /* make sure that uboot passed pointer to cmdline/dtb is valid */
machine_desc = setup_machine_fdt(__dtb_start); if (uboot_tag && is_kernel((unsigned long)uboot_arg))
if (!machine_desc) panic("Invalid uboot arg\n");
panic("Embedded DT invalid\n");
/* See if u-boot passed an external Device Tree blob */
/* Append any u-boot provided cmdline */ machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */
#ifdef CONFIG_CMDLINE_UBOOT if (!machine_desc) {
/* Add a whitespace seperator between the 2 cmdlines */ /* No, so try the embedded one */
strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); machine_desc = setup_machine_fdt(__dtb_start);
strlcat(boot_command_line, command_line, COMMAND_LINE_SIZE); if (!machine_desc)
#endif panic("Embedded DT invalid\n");
/*
* If we are here, it is established that @uboot_arg didn't
* point to DT blob. Instead if u-boot says it is cmdline,
* Appent to embedded DT cmdline.
* setup_machine_fdt() would have populated @boot_command_line
*/
if (uboot_tag == 1) {
/* Ensure a whitespace between the 2 cmdlines */
strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
strlcat(boot_command_line, uboot_arg,
COMMAND_LINE_SIZE);
}
}
/* Save unparsed command line copy for /proc/cmdline */ /* Save unparsed command line copy for /proc/cmdline */
*cmdline_p = boot_command_line; *cmdline_p = boot_command_line;
......
...@@ -197,51 +197,65 @@ int __init setup_profiling_timer(unsigned int multiplier) ...@@ -197,51 +197,65 @@ int __init setup_profiling_timer(unsigned int multiplier)
/* Inter Processor Interrupt Handling */ /* Inter Processor Interrupt Handling */
/*****************************************************************************/ /*****************************************************************************/
/*
* structures for inter-processor calls
* A Collection of single bit ipi messages
*
*/
/*
* TODO_rajesh investigate tlb message types.
* IPI Timer not needed because each ARC has an individual Interrupting Timer
*/
enum ipi_msg_type { enum ipi_msg_type {
IPI_NOP = 0, IPI_EMPTY = 0,
IPI_RESCHEDULE = 1, IPI_RESCHEDULE = 1,
IPI_CALL_FUNC, IPI_CALL_FUNC,
IPI_CPU_STOP IPI_CPU_STOP,
}; };
struct ipi_data { /*
unsigned long bits; * In arches with IRQ for each msg type (above), receiver can use IRQ-id to
}; * figure out what msg was sent. For those which don't (ARC has dedicated IPI
* IRQ), the msg-type needs to be conveyed via per-cpu data
*/
static DEFINE_PER_CPU(struct ipi_data, ipi_data); static DEFINE_PER_CPU(unsigned long, ipi_data);
static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg) static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
{ {
unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
unsigned long old, new;
unsigned long flags; unsigned long flags;
unsigned int cpu;
pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
local_irq_save(flags); local_irq_save(flags);
for_each_cpu(cpu, callmap) { /*
struct ipi_data *ipi = &per_cpu(ipi_data, cpu); * Atomically write new msg bit (in case others are writing too),
set_bit(msg, &ipi->bits); * and read back old value
} */
do {
new = old = *ipi_data_ptr;
new |= 1U << msg;
} while (cmpxchg(ipi_data_ptr, old, new) != old);
/* Call the platform specific cross-CPU call function */ /*
if (plat_smp_ops.ipi_send) * Call the platform specific IPI kick function, but avoid if possible:
plat_smp_ops.ipi_send((void *)callmap); * Only do so if there's no pending msg from other concurrent sender(s).
* Otherwise, recevier will see this msg as well when it takes the
* IPI corresponding to that msg. This is true, even if it is already in
* IPI handler, because !@old means it has not yet dequeued the msg(s)
* so @new msg can be a free-loader
*/
if (plat_smp_ops.ipi_send && !old)
plat_smp_ops.ipi_send(cpu);
local_irq_restore(flags); local_irq_restore(flags);
} }
static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
{
unsigned int cpu;
for_each_cpu(cpu, callmap)
ipi_send_msg_one(cpu, msg);
}
void smp_send_reschedule(int cpu) void smp_send_reschedule(int cpu)
{ {
ipi_send_msg(cpumask_of(cpu), IPI_RESCHEDULE); ipi_send_msg_one(cpu, IPI_RESCHEDULE);
} }
void smp_send_stop(void) void smp_send_stop(void)
...@@ -254,7 +268,7 @@ void smp_send_stop(void) ...@@ -254,7 +268,7 @@ void smp_send_stop(void)
void arch_send_call_function_single_ipi(int cpu) void arch_send_call_function_single_ipi(int cpu)
{ {
ipi_send_msg(cpumask_of(cpu), IPI_CALL_FUNC); ipi_send_msg_one(cpu, IPI_CALL_FUNC);
} }
void arch_send_call_function_ipi_mask(const struct cpumask *mask) void arch_send_call_function_ipi_mask(const struct cpumask *mask)
...@@ -265,33 +279,29 @@ void arch_send_call_function_ipi_mask(const struct cpumask *mask) ...@@ -265,33 +279,29 @@ void arch_send_call_function_ipi_mask(const struct cpumask *mask)
/* /*
* ipi_cpu_stop - handle IPI from smp_send_stop() * ipi_cpu_stop - handle IPI from smp_send_stop()
*/ */
static void ipi_cpu_stop(unsigned int cpu) static void ipi_cpu_stop(void)
{ {
machine_halt(); machine_halt();
} }
static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu) static inline void __do_IPI(unsigned long msg)
{ {
unsigned long msg = 0; switch (msg) {
case IPI_RESCHEDULE:
scheduler_ipi();
break;
do { case IPI_CALL_FUNC:
msg = find_next_bit(ops, BITS_PER_LONG, msg+1); generic_smp_call_function_interrupt();
break;
switch (msg) { case IPI_CPU_STOP:
case IPI_RESCHEDULE: ipi_cpu_stop();
scheduler_ipi(); break;
break;
case IPI_CALL_FUNC:
generic_smp_call_function_interrupt();
break;
case IPI_CPU_STOP:
ipi_cpu_stop(cpu);
break;
}
} while (msg < BITS_PER_LONG);
default:
pr_warn("IPI with unexpected msg %ld\n", msg);
}
} }
/* /*
...@@ -300,19 +310,25 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu) ...@@ -300,19 +310,25 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu)
*/ */
irqreturn_t do_IPI(int irq, void *dev_id) irqreturn_t do_IPI(int irq, void *dev_id)
{ {
int cpu = smp_processor_id(); unsigned long pending;
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
unsigned long ops; pr_debug("IPI [%ld] received on cpu %d\n",
*this_cpu_ptr(&ipi_data), smp_processor_id());
if (plat_smp_ops.ipi_clear) if (plat_smp_ops.ipi_clear)
plat_smp_ops.ipi_clear(cpu, irq); plat_smp_ops.ipi_clear(irq);
/* /*
* XXX: is this loop really needed * "dequeue" the msg corresponding to this IPI (and possibly other
* And do we need to move ipi_clean inside * piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
*/ */
while ((ops = xchg(&ipi->bits, 0)) != 0) pending = xchg(this_cpu_ptr(&ipi_data), 0);
__do_IPI(&ops, ipi, cpu);
do {
unsigned long msg = __ffs(pending);
__do_IPI(msg);
pending &= ~(1U << msg);
} while (pending);
return IRQ_HANDLED; return IRQ_HANDLED;
} }
......
...@@ -88,18 +88,14 @@ void iss_model_init_smp(unsigned int cpu) ...@@ -88,18 +88,14 @@ void iss_model_init_smp(unsigned int cpu)
smp_ipi_irq_setup(cpu, IDU_INTERRUPT_0 + cpu); smp_ipi_irq_setup(cpu, IDU_INTERRUPT_0 + cpu);
} }
static void iss_model_ipi_send(void *arg) static void iss_model_ipi_send(int cpu)
{ {
struct cpumask *callmap = arg; idu_irq_assert(cpu);
unsigned int cpu;
for_each_cpu(cpu, callmap)
idu_irq_assert(cpu);
} }
static void iss_model_ipi_clear(int cpu, int irq) static void iss_model_ipi_clear(int irq)
{ {
idu_irq_clear(IDU_INTERRUPT_0 + cpu); idu_irq_clear(IDU_INTERRUPT_0 + smp_processor_id());
} }
void iss_model_init_early_smp(void) void iss_model_init_early_smp(void)
......
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