From 534103061c5e30aa4c2e087da56e52d70cb92a01 Mon Sep 17 00:00:00 2001
From: Abdur-Rahman Mansoor <armansoor@missingno.dev>
Date: Wed, 31 Jul 2024 15:10:13 -0400
Subject: [PATCH] important bug fix and some micro optimizations

As for the fix, the submission queues weren't properly being zeroed out
due to a small typo. The other stuff has some commented out stuff that
I'm currently debugging and working on.
---
 drivers/nvme/nvme.asm | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/drivers/nvme/nvme.asm b/drivers/nvme/nvme.asm
index 778f730..8c77c1d 100644
--- a/drivers/nvme/nvme.asm
+++ b/drivers/nvme/nvme.asm
@@ -972,7 +972,7 @@ proc nvme_init stdcall, pci:dword
 	jz 	.exit_fail
 	mov 	dword [edi + ecx + NVM_QUEUE_ENTRY.sq_ptr], eax
 	push 	ecx
-	stdcall memsetdz, eax, sizeof.CQ_ENTRY * CQ_ENTRIES / 4
+	stdcall memsetdz, eax, sizeof.SQ_ENTRY * SQ_ENTRIES / 4
 	invoke  CreateRingBuffer, 0x1000, PG_SW
 	pop 	ecx
 	test 	eax, eax
@@ -989,23 +989,19 @@ proc nvme_init stdcall, pci:dword
 	mov 	dword [edi + ecx + NVM_QUEUE_ENTRY.cmd_ptr], eax
 	mov  	esi, eax
 	push 	ecx
-	xor 	ecx, ecx
+	xor 	ebx, ebx
 
 .init_cmd_entries:
-	push 	ecx
 	; BUG: Won't pop ecx if allocation fails
 	invoke  KernelAlloc, sizeof.MUTEX
 	test 	eax, eax
 	jz 	.exit_fail
-	pop 	ecx
-	mov 	dword [esi + ecx * NVMQCMD.mutex_ptr], eax
-	mov 	dword [esi + ecx * NVMQCMD.cid], ecx
-	push 	ecx
+	mov 	dword [esi + ebx * NVMQCMD.mutex_ptr], eax
+	mov 	dword [esi + ebx * NVMQCMD.cid], ebx
 	mov 	ecx, eax
 	invoke  MutexInit
-	pop 	ecx
-	inc 	ecx
-	cmp 	ecx, CQ_ENTRIES
+	inc 	ebx
+	cmp 	ebx, CQ_ENTRIES
 	jne 	.init_cmd_entries
 
 	pop 	ecx
@@ -1108,7 +1104,7 @@ proc nvme_init stdcall, pci:dword
 	jnz	.exit_fail
 
 	; Create I/O Queues
-	; (TODO: create N queue pairs for N CPU cores, see page 8 of NVMe 1.4 spec for an explaination
+	; (TODO: create N queue pairs for N CPU cores, see page 8 of NVMe 1.4 spec for an explaination)
 	mov 	esi, [pci]
 	mov 	edi, esi
 	mov 	esi, dword [esi + pcidev.queue_entries]
@@ -1215,13 +1211,11 @@ endp
 
 proc get_new_cid stdcall, pci:dword, y:dword
 
-	push 	esi
-	mov 	esi, [pci]
-	mov 	esi, [esi + pcidev.queue_entries]
+	mov 	eax, [pci]
+	mov 	eax, dword [eax + pcidev.queue_entries]
 	mov 	ecx, [y]
 	imul 	ecx, sizeof.NVM_QUEUE_ENTRY
-	movzx 	eax, word [esi + ecx + NVM_QUEUE_ENTRY.tail]
-	pop 	esi
+	movzx 	eax, word [eax + ecx + NVM_QUEUE_ENTRY.head]
 	ret
 
 endp
@@ -1316,7 +1310,7 @@ proc cqyhdbl_write stdcall, pci:dword, y:dword, cqh:dword
 	lea 	edi, dword [edi + ecx]
 	mov 	esi, dword [esi + pcidev.io_addr]
 	mov 	eax, [cqh]
-	;DEBUGF  DBG_INFO, "Writing to completion queue doorbell register: %u\n", ax
+	;DEBUGF  DBG_INFO, "Writing to completion queue doorbell register 0x%x: %u\n", edx, ax
 	mov 	word [esi + edx], ax ; Write to CQyHDBL
 	mov 	word [edi + NVM_QUEUE_ENTRY.head], ax
 	pop 	edi esi
@@ -1332,13 +1326,18 @@ proc sqytdbl_write stdcall, pci:dword, y:word, cmd:dword
 	mov 	edi, dword [edi + pcidev.queue_entries]
 	movzx 	ecx, [y]
 	imul 	ecx, sizeof.NVM_QUEUE_ENTRY
+	;mov 	eax, dword [edi + ecx + NVM_QUEUE_ENTRY.cmd_ptr]
 	mov 	edi, dword [edi + ecx + NVM_QUEUE_ENTRY.sq_ptr]
 	mov 	esi, [cmd]
 	mov 	ecx, dword [esi + SQ_ENTRY.cdw0]
 	shr 	ecx, 16 ; Get CID
 	imul 	ecx, sizeof.SQ_ENTRY
 	lea 	edi, [edi + ecx]
+	;mov 	ecx, [eax + ecx + NVMQCMD.mutex_ptr]
+	;push 	ecx
 	stdcall memcpy, edi, esi, sizeof.SQ_ENTRY
+	;pop 	ecx
+	;invoke  MutexLock
 
 	mov 	edi, [pci]
 	mov 	esi, dword [edi + pcidev.io_addr]
@@ -1419,9 +1418,9 @@ proc consume_cq_entries stdcall, pci:dword, queue:dword
 	mov 	edi, dword [esi + NVM_QUEUE_ENTRY.cq_ptr]
 	movzx 	eax, word [esi + NVM_QUEUE_ENTRY.tail]
 	movzx 	ecx, word [esi + NVM_QUEUE_ENTRY.head]
-	stdcall is_queue_full, eax, ecx
-	test 	eax, eax
-	jnz 	.end
+	;stdcall is_queue_full, eax, ecx
+	;test 	eax, eax
+	;jnz 	.end
 	movzx 	ecx, word [esi + NVM_QUEUE_ENTRY.head]
 	cmp 	ecx, (NVM_ACQS - 1)
 	jb 	.loop