feat: implement determine_active_nsids

drivers/nvme/nvme.asm

@@ -165,6 +165,72 @@ proc create_namespace stdcall, pci:dword, cid:word
 
 endp
 
+; See page 248 of the NVMe 1.4 specification for reference
+proc determine_active_nsids stdcall, pci:dword
+
+		push 	esi edi ebx
+		xor 	esi, esi
+		xor 	edi, edi
+		invoke  KernelAlloc, 0x1000
+		test 	eax, eax
+		jz 		.fail
+		mov 	esi, eax
+		invoke  GetPhysAddr
+		stdcall nvme_identify, [pci], 0, eax, CNS_IDCS
+		mov 	eax, dword [esi + IDENTC.nn]
+		test 	eax, eax
+		jz 		.fail
+		invoke  KernelAlloc, 0x1000
+		test 	eax, eax
+		jz 		.fail
+		mov 	edi, eax
+		invoke  GetPhysAddr
+		mov 	ebx, eax
+		xor 	ecx, ecx
+
+.loop:
+		cmp 	ecx, dword [esi + IDENTC.nn]
+		jg 		.success
+		stdcall nvme_identify, [pci], ecx, ebx, CNS_IDNS
+		push 	ecx
+		xor 	ecx, ecx
+
+.inner_loop:
+		mov 	eax, dword [edi + ecx * 4]
+		test 	eax, eax
+		jnz 	.is_active_nsid
+		inc 	ecx
+		cmp 	ecx, 0x1000 / 4
+		jne 	.inner_loop
+		pop 	ecx
+		inc 	ecx
+		jmp 	.loop
+
+.is_active_nsid:
+		pop 	ecx ; pop active NSID value into ecx
+		mov 	eax, [pci]
+		mov 	eax, dword [eax + pcidev.nsids]
+		mov 	dword [eax + ecx * 4], ecx
+		inc 	ecx
+		jmp 	.loop
+
+.fail:
+		invoke  KernelFree, esi ; assumes KernelFree can check if its nullptr (hopefully)
+		invoke  KernelFree, edi
+		pop 	ebx edi esi
+		xor 	eax, eax
+		ret
+
+.success:
+		invoke  KernelFree, esi
+		invoke  KernelFree, edi
+		pop 	ebx edi esi
+		xor 	eax, eax
+		inc 	eax
+		ret
+		
+endp
+
 ; See page 101 of the NVMe 1.4 specification for reference
 proc create_io_completion_queue stdcall, pci:dword, prp1:dword, qid:dword, ien:byte