On Mon, 1 Sep 2014 22:57:47 +0800, Hanjun Guo hanjun.guo@linaro.org wrote:
MADT contains the information for MPIDR which is essential for SMP initialization, parse the GIC cpu interface structures to get the MPIDR value and map it to cpu_logical_map(), and add enabled cpu with valid MPIDR into cpu_possible_map.
ACPI 5.1 only has two explicit methods to boot up SMP, PSCI and Parking protocol, but the Parking protocol is only specified for ARMv7 now, so make PSCI as the only way for the SMP boot protocol before some updates for the ACPI spec or the Parking protocol spec.
Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org
+/**
- acpi_map_gic_cpu_interface - generates a logical cpu number
- and map to MPIDR represented by GICC structure
- @mpidr: CPU's hardware id to register, MPIDR represented in MADT
- @enabled: this cpu is enabled or not
- Returns the logical cpu number which maps to MPIDR
- */
+static int acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled) +{
- int cpu;
- if (mpidr == INVALID_HWID) {
pr_info("Skip invalid cpu hardware ID\n");
return -EINVAL;
- }
- total_cpus++;
- if (!enabled)
return -EINVAL;
- if (enabled_cpus >= NR_CPUS) {
pr_warn("NR_CPUS limit of %d reached, Processor %d/0x%llx ignored.\n",
NR_CPUS, total_cpus, mpidr);
return -EINVAL;
- }
- /* No need to check duplicate MPIDRs for the first CPU */
- if (enabled_cpus) {
/*
* Duplicate MPIDRs are a recipe for disaster. Scan
* all initialized entries and check for
* duplicates. If any is found just ignore the CPU.
*/
for_each_possible_cpu(cpu) {
if (cpu_logical_map(cpu) == mpidr) {
pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n",
mpidr);
return -EINVAL;
}
}
- } else {
/* Fist GICC entry must be BSP as ACPI spec said */
if (cpu_logical_map(0) != mpidr) {
pr_err("First GICC entry is not BSP for MPIDR 0x%llx\n",
mpidr);
return -EINVAL;
}
- }
- /* allocate a logical cpu id for the new comer */
- if (cpu_logical_map(0) == mpidr) {
/*
* boot_cpu_init() already hold bit 0 in cpu_present_mask
* for BSP, no need to allocate again.
*/
cpu = 0;
- } else {
cpu = cpumask_next_zero(-1, cpu_possible_mask);
- }
Nit: so the above two if/else blocks are essentially testing for the same condition: Is this the first cpu? or a secondary cpu? I would merge the two into a single if/else block.
g.