Unverified Commit 2ac87434 authored by Conor Dooley's avatar Conor Dooley Committed by Palmer Dabbelt
Browse files

RISC-V: split early & late of_node to hartid mapping 

Some back and forth with Drew [1] about riscv_fill_hwcap() resulted in
the realisation that it is not very useful to parse the DT & perform
validation of riscv,isa every time we would like to get the id for a
hart.

Although it is no longer called in riscv_fill_hwcap(),
riscv_of_processor_hartid() is called in several other places.
Notably in setup_smp() it forms part of the logic for filling the mask
of possible CPUs. Since a possible CPU must have passed this basic
validation of riscv,isa, a repeat validation is not required.

Rename riscv_of_processor_id() to riscv_early_of_processor_id(),
which will be called from setup_smp() & introduce a new
riscv_of_processor_id() which makes use of the pre-populated mask of
possible cpus.

Link: https://lore.kernel.org/linux-riscv/xvdswl3iyikwvamny7ikrxo2ncuixshtg3f6uucjahpe3xpc5c@ud4cz4fkg5dj/

 [1]
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Signed-off-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarSunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-glade-pastel-d8cbd9d9f3c6@spud


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent fed14be4

arch/riscv/include/asm/processor.h

+1 −0
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ static inline void wait_for_interrupt(void) 


struct device_node;

int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);

int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hartid);

int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid);



extern void riscv_fill_hwcap(void);

arch/riscv/kernel/cpu.c

+21 −1
Original line number Diff line number Diff line
@@ -22,6 +22,26 @@ 
 * isn't an enabled and valid RISC-V hart node.

 */

int riscv_of_processor_hartid(struct device_node *node, unsigned long *hart)

{

	int cpu;



	*hart = (unsigned long)of_get_cpu_hwid(node, 0);

	if (*hart == ~0UL) {

		pr_warn("Found CPU without hart ID\n");

		return -ENODEV;

	}



	cpu = riscv_hartid_to_cpuid(*hart);

	if (cpu < 0)

		return cpu;



	if (!cpu_possible(cpu))

		return -ENODEV;



	return 0;

}



int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hart)

{

	const char *isa;

arch/riscv/kernel/smpboot.c

+1 −1
Original line number Diff line number Diff line
@@ -148,7 +148,7 @@ static void __init of_parse_and_init_cpus(void) 
	cpu_set_ops(0);



	for_each_of_cpu_node(dn) {

		rc = riscv_of_processor_hartid(dn, &hart);

		rc = riscv_early_of_processor_hartid(dn, &hart);

		if (rc < 0)

			continue;