1	# bend-osdev-acpi, rsdt.bend: the Root and Extended System Description
2	# Tables (ACPI 6.5, sections 5.2.7 and 5.2.8): a header, then the physical
3	# addresses of the other tables, 4 bytes each in the RSDT ("RSDT"), 8 bytes
4	# each in the XSDT ("XSDT"). Addresses are answered as W64 for both.
5	import Base
6	import bend-osdev-word64@0.1.1.1/word64.bend as W
7	import bend-osdev-bytes@0.1.1.1/bytes.bend as B
8	import ./error.bend as E
9	import ./header.bend as H
10	import ./fields.bend as F
11	
12	type AcpiSdtList is Data:
13	  AcpiSdtList{header: H.AcpiHeader, entries: List<&2, W.W64>}
14	
15	def AcpiSdtList.entries(t: AcpiSdtList) -> List<&2, W.W64>:
16	  match t:
17	    case AcpiSdtList{h, es}:
18	      es
19	
20	def AcpiSdtList.header(t: AcpiSdtList) -> H.AcpiHeader:
21	  match t:
22	    case AcpiSdtList{h, es}:
23	      h
24	
25	def sl.rev(xs: List<&2, W.W64>, acc: List<&2, W.W64>) -> List<&2, W.W64>:
26	  match xs:
27	    case Nil{}:
28	      acc
29	    case Con{h, t}:
30	      sl.rev(t, Con{h, acc})
31	
32	# n entries of width 4 or 8 bytes from the front of o
33	def sl.read(n: Nat, wide: Bool, +o: B.Octets, acc: List<&2, W.W64>) -> List<&2, W.W64>:
34	  match n:
35	    case 0n:
36	      sl.rev(acc, Nil{})
37	    case 1n+p:
38	      match wide:
39	        case True{}:
40	          sl.read(p, True{}, B.Octets.drop(8n, o), Con{F.AcpiF.u64(o, 0n), acc})
41	        case False{}:
42	          sl.read(p, False{}, B.Octets.drop(4n, o), Con{W.W64.from_u32(F.AcpiF.u32(o, 0n)), acc})
43	
44	def sl.width(wide: Bool) -> Nat:
45	  match wide:
46	    case True{}:
47	      8n
48	    case False{}:
49	      4n
50	
51	def sl.body(ok: Bool, +wide: Bool, +h: H.AcpiHeader, +body: B.Octets) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
52	  match ok:
53	    case False{}:
54	      Fail{E.AcpiBadSize{B.Octets.len(body)}}
55	    case True{}:
56	      Done{AcpiSdtList{h, sl.read(Nat.div(B.Octets.len(body), sl.width(wide)), wide, body, Nil{})}}
57	
58	# a checked table's body as entries; AcpiBadSize if it is not a whole
59	# number of them
60	def sl.of_sdt(+wide: Bool, t: H.AcpiSdt) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
61	  match t:
62	    case H.AcpiSdt{h, +body}:
63	      sl.body(Nat.is_eq(Nat.mod(B.Octets.len(body), sl.width(wide)), 0n), wide, h, body)
64	
65	def AcpiRsdt.of_sdt(t: H.AcpiSdt) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
66	  sl.of_sdt(False{}, t)
67	
68	def AcpiXsdt.of_sdt(t: H.AcpiSdt) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
69	  sl.of_sdt(True{}, t)
70	
71	def sl.parse(+wide: Bool, r: Result<&2, &2, E.AcpiError, H.AcpiSdt>) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
72	  match r:
73	    case Fail{e}:
74	      Fail{e}
75	    case Done{t}:
76	      sl.of_sdt(wide, t)
77	
78	def AcpiRsdt.parse(+o: B.Octets) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
79	  sl.parse(False{}, H.AcpiSdt.parse_sig(B.Octets.of_string("RSDT"), o))
80	
81	def AcpiXsdt.parse(+o: B.Octets) -> Result<&2, &2, E.AcpiError, AcpiSdtList>:
82	  sl.parse(True{}, H.AcpiSdt.parse_sig(B.Octets.of_string("XSDT"), o))
83	
84	def sl.enc(xs: List<&2, W.W64>, wide: Bool) -> List<&2, B.Octets>:
85	  match xs:
86	    case Nil{}:
87	      Nil{}
88	    case Con{h, t}:
89	      match wide:
90	        case True{}:
91	          Con{B.Octets.le64(h), sl.enc(t, True{})}
92	        case False{}:
93	          Con{B.Octets.le32(W.W64.lo(h)), sl.enc(t, False{})}
94	
95	# the table (header from H.AcpiHeader.make or decoded; its signature is
96	# replaced, its length and checksum computed). RSDT entries keep the low 32
97	# bits of each address.
98	def AcpiRsdt.build(h: H.AcpiHeader, xs: List<&2, W.W64>) -> B.Octets:
99	  match h:
100	    case H.AcpiHeader{s, l, r, c, o, t, orv, ci, cr}:
101	      H.AcpiSdt.build(H.AcpiHeader{B.Octets.of_string("RSDT"), l, r, c, o, t, orv, ci, cr}, B.Octets.concat(sl.enc(xs, False{})))
102	
103	def AcpiXsdt.build(h: H.AcpiHeader, xs: List<&2, W.W64>) -> B.Octets:
104	  match h:
105	    case H.AcpiHeader{s, l, r, c, o, t, orv, ci, cr}:
106	      H.AcpiSdt.build(H.AcpiHeader{B.Octets.of_string("XSDT"), l, r, c, o, t, orv, ci, cr}, B.Octets.concat(sl.enc(xs, True{})))