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drivers/bus: arm-cci: function to enable CCI ports from early boot code 

This provides cci_enable_port_for_self().  This is the counterpart to
cci_disable_port_by_cpu(self).

This is meant to be called from the MCPM machine specific power_up_setup
callback code when the appropriate affinity level needs to be initialized.
The code therefore has to be position independent as the MMU is still off
and it cannot rely on any stack space.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Dave Martin <dave.martin@linaro.org>
This commit is contained in:
Nicolas Pitre 2013-05-21 23:34:41 -04:00
parent ed69bdd8fd
commit 62158f817a
1 changed files with 113 additions and 6 deletions
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119
drivers/bus/arm-cci.c
View File

@ -43,6 +43,7 @@ enum cci_ace_port_type {
struct cci_ace_port {
void __iomem *base;
unsigned long phys;
enum cci_ace_port_type type;
struct device_node *dn;
};
@ -51,11 +52,13 @@ static struct cci_ace_port *ports;
static unsigned int nb_cci_ports;
static void __iomem *cci_ctrl_base;
static unsigned long cci_ctrl_phys;
struct cpu_port {
u64 mpidr;
u32 port;
};
/*
* Use the port MSB as valid flag, shift can be made dynamic
* by computing number of bits required for port indexes.
@ -229,6 +232,102 @@ int notrace cci_disable_port_by_cpu(u64 mpidr)
}
EXPORT_SYMBOL_GPL(cci_disable_port_by_cpu);
/**
* cci_enable_port_for_self() - enable a CCI port for calling CPU
*
* Enabling a CCI port for the calling CPU implies enabling the CCI
* port controlling that CPU's cluster. Caller must make sure that the
* CPU running the code is the first active CPU in the cluster and all
* other CPUs are quiescent in a low power state or waiting for this CPU
* to complete the CCI initialization.
*
* Because this is called when the MMU is still off and with no stack,
* the code must be position independent and ideally rely on callee
* clobbered registers only. To achieve this we must code this function
* entirely in assembler.
*
* On success this returns with the proper CCI port enabled. In case of
* any failure this never returns as the inability to enable the CCI is
* fatal and there is no possible recovery at this stage.
*/
asmlinkage void __naked cci_enable_port_for_self(void)
{
asm volatile ("\n"
" mrc p15, 0, r0, c0, c0, 5 @ get MPIDR value \n"
" and r0, r0, #"__stringify(MPIDR_HWID_BITMASK)" \n"
" adr r1, 5f \n"
" ldr r2, [r1] \n"
" add r1, r1, r2 @ &cpu_port \n"
" add ip, r1, %[sizeof_cpu_port] \n"
/* Loop over the cpu_port array looking for a matching MPIDR */
"1: ldr r2, [r1, %[offsetof_cpu_port_mpidr_lsb]] \n"
" cmp r2, r0 @ compare MPIDR \n"
" bne 2f \n"
/* Found a match, now test port validity */
" ldr r3, [r1, %[offsetof_cpu_port_port]] \n"
" tst r3, #"__stringify(PORT_VALID)" \n"
" bne 3f \n"
/* no match, loop with the next cpu_port entry */
"2: add r1, r1, %[sizeof_struct_cpu_port] \n"
" cmp r1, ip @ done? \n"
" blo 1b \n"
/* CCI port not found -- cheaply try to stall this CPU */
"cci_port_not_found: \n"
" wfi \n"
" wfe \n"
" b cci_port_not_found \n"
/* Use matched port index to look up the corresponding ports entry */
"3: bic r3, r3, #"__stringify(PORT_VALID)" \n"
" adr r0, 6f \n"
" ldmia r0, {r1, r2} \n"
" sub r1, r1, r0 @ virt - phys \n"
" ldr r0, [r0, r2] @ *(&ports) \n"
" mov r2, %[sizeof_struct_ace_port] \n"
" mla r0, r2, r3, r0 @ &ports[index] \n"
" sub r0, r0, r1 @ virt_to_phys() \n"
/* Enable the CCI port */
" ldr r0, [r0, %[offsetof_port_phys]] \n"
" mov r3, #"__stringify(CCI_ENABLE_REQ)" \n"
" str r3, [r0, #"__stringify(CCI_PORT_CTRL)"] \n"
/* poll the status reg for completion */
" adr r1, 7f \n"
" ldr r0, [r1] \n"
" ldr r0, [r0, r1] @ cci_ctrl_base \n"
"4: ldr r1, [r0, #"__stringify(CCI_CTRL_STATUS)"] \n"
" tst r1, #1 \n"
" bne 4b \n"
" mov r0, #0 \n"
" bx lr \n"
" .align 2 \n"
"5: .word cpu_port - . \n"
"6: .word . \n"
" .word ports - 6b \n"
"7: .word cci_ctrl_phys - . \n"
: :
[sizeof_cpu_port] "i" (sizeof(cpu_port)),
#ifndef __ARMEB__
[offsetof_cpu_port_mpidr_lsb] "i" (offsetof(struct cpu_port, mpidr)),
#else
[offsetof_cpu_port_mpidr_lsb] "i" (offsetof(struct cpu_port, mpidr)+4),
#endif
[offsetof_cpu_port_port] "i" (offsetof(struct cpu_port, port)),
[sizeof_struct_cpu_port] "i" (sizeof(struct cpu_port)),
[sizeof_struct_ace_port] "i" (sizeof(struct cci_ace_port)),
[offsetof_port_phys] "i" (offsetof(struct cci_ace_port, phys)) );
unreachable();
}
/**
* __cci_control_port_by_device() - function to control a CCI port by device
* reference
@ -306,6 +405,7 @@ static int __init cci_probe(void)
struct cci_nb_ports const *cci_config;
int ret, i, nb_ace = 0, nb_ace_lite = 0;
struct device_node *np, *cp;
struct resource res;
const char *match_str;
bool is_ace;
@ -323,9 +423,12 @@ static int __init cci_probe(void)
if (!ports)
return -ENOMEM;
cci_ctrl_base = of_iomap(np, 0);
if (!cci_ctrl_base) {
ret = of_address_to_resource(np, 0, &res);
if (!ret) {
cci_ctrl_base = ioremap(res.start, resource_size(&res));
cci_ctrl_phys = res.start;
}
if (ret || !cci_ctrl_base) {
WARN(1, "unable to ioremap CCI ctrl\n");
ret = -ENXIO;
goto memalloc_err;
@ -353,9 +456,12 @@ static int __init cci_probe(void)
continue;
}
ports[i].base = of_iomap(cp, 0);
if (!ports[i].base) {
ret = of_address_to_resource(cp, 0, &res);
if (!ret) {
ports[i].base = ioremap(res.start, resource_size(&res));
ports[i].phys = res.start;
}
if (ret || !ports[i].base) {
WARN(1, "unable to ioremap CCI port %d\n", i);
continue;
}
@ -382,6 +488,7 @@ static int __init cci_probe(void)
* cluster power-up/power-down. Make sure it reaches main memory.
*/
sync_cache_w(&cci_ctrl_base);
sync_cache_w(&cci_ctrl_phys);
sync_cache_w(&ports);
sync_cache_w(&cpu_port);
__sync_cache_range_w(ports, sizeof(*ports) * nb_cci_ports);