MODULE SdDisks;
(**
	AUTHOR Timothée Martiel, 12/2015
	PURPOSE Disk interface for the SD card driver
*)

IMPORT
	SYSTEM,
	Disks, Strings,
	Sd, SdEnvironment,
	Trace;

CONST
	(** Base name for SD block devices *)
	BaseDevName = "SD";
	(** Number of entries used in the cache *)
	CacheSize = 32;

TYPE
	(** SD Block Device *)
	BlockDevice * = POINTER TO BlockDeviceDesc;
	BlockDeviceDesc * = RECORD (Disks.BlockDeviceDesc)
		card: Sd.Card;
		bufferSize: LONGINT;
		cache: POINTER TO ARRAY OF CacheEntry;
		nextSd: BlockDevice;
	END;

	(** SD cache entry. *)
	CacheEntry = RECORD
		buffer: POINTER TO ARRAY OF CHAR;
		au: LONGINT;
		active, mod: BOOLEAN;
	END;

	(** Create a new block device for the specified card *)
	PROCEDURE InitBlockDevice * (d: BlockDevice; card: Sd.Card);
	VAR
		name, id: ARRAY 32 OF CHAR;
		ignore, i: LONGINT;
	BEGIN
		name := BaseDevName;
		Strings.IntToStr(devId, id);
		INC(devId);
		Strings.Append(name, id);
		Disks.InitBlockDevice(d, name);
		d.bufferSize := card.sdStatus.auSize DIV Sd.BlockSize;
		NEW(d.cache, CacheSize);
		FOR i := 0 TO CacheSize - 1 DO NEW(d.cache[i].buffer, d.bufferSize * Sd.BlockSize) END;

		d.blockSize := Sd.BlockSize;
		d.Read := Read;
		d.Write := Write;
		d.Open := Open;
		d.Close := Close;
		d.Reset := Reset;
		d.GetSize := GetSize;
		d.Handle := Handle;
		d.card := card
	END InitBlockDevice;

	(** Read blocks from SD card *)
	PROCEDURE Read (dev: Disks.BlockDevice;  block, num: LONGINT; VAR data: ARRAY OF SYSTEM.BYTE; ofs: LONGINT; VAR res: LONGINT);
	VAR
		au, auOfs, idx, size, s: LONGINT;
	BEGIN
		WITH dev: BlockDevice DO
			size := num * Sd.BlockSize;
			WHILE size > 0 DO
				au := block DIV dev.bufferSize;
				auOfs := block MOD dev.bufferSize;
				idx := au MOD CacheSize;
				IF ~UpdateCacheEntry(dev, dev.cache[idx], au, res) THEN RETURN END;
				s := MIN(size, (dev.bufferSize - auOfs) * Sd.BlockSize);
				SYSTEM.MOVE(ADDRESSOF(dev.cache[idx].buffer[auOfs * Sd.BlockSize]), ADDRESSOF(data[ofs]), s);
				DEC(size, s);
				INC(ofs, s);
				INC(block, s DIV Sd.BlockSize)
			END
		END
	END Read;

	(** Write blocks to SD card *)
	PROCEDURE Write (dev: Disks.BlockDevice;  block, num: LONGINT; VAR data: ARRAY OF SYSTEM.BYTE; ofs: LONGINT; VAR res: LONGINT);
	VAR
		au, auOfs, idx, size, s: LONGINT;
	BEGIN
		WITH dev: BlockDevice DO
			size := num * Sd.BlockSize;
			WHILE size > 0 DO
				au := block DIV dev.bufferSize;
				auOfs := block MOD dev.bufferSize;
				idx := au MOD CacheSize;
				IF ~UpdateCacheEntry(dev, dev.cache[idx], au, res) THEN RETURN END;
				dev.cache[idx].mod := TRUE;
				s := MIN(size, (dev.bufferSize - auOfs) * Sd.BlockSize);
				ASSERT(ofs + s <= LEN(data));
				ASSERT(auOfs * Sd.BlockSize + s <= LEN(dev.cache[idx].buffer));
				SYSTEM.MOVE(ADDRESSOF(data[ofs]), ADDRESSOF(dev.cache[idx].buffer[auOfs * Sd.BlockSize]), s);
				DEC(size, s);
				INC(ofs, s);
				INC(block, s DIV Sd.BlockSize)
			END
		END
	END Write;

	(** Update cache entry to make sure it contains the data for the given au *)
	PROCEDURE UpdateCacheEntry (dev: BlockDevice; VAR cache: CacheEntry; au: LONGINT; VAR res: LONGINT): BOOLEAN;
	VAR
		ignore: BOOLEAN;
	BEGIN
		IF ~cache.active OR (cache.au # au) THEN
			IF cache.active & cache.mod THEN
				IF ~Sd.Write(dev.card, cache.au * dev.bufferSize, dev.bufferSize * Sd.BlockSize, cache.buffer^, 0, res) THEN
					RETURN FALSE
				END;
			END;
			IF ~Sd.Read(dev.card, au * dev.bufferSize, dev.bufferSize * Sd.BlockSize, cache.buffer^, 0, res) THEN
				RETURN FALSE
			END;
			cache.active := TRUE;
			cache.mod := FALSE;
			cache.au := au
		END;
		RETURN TRUE
	END UpdateCacheEntry;

	(** Open a device: turn LED on *)
	PROCEDURE Open (dev: Disks.BlockDevice; VAR res: LONGINT);
	BEGIN
		Sd.SetLedState(dev(BlockDevice).card.hc, TRUE)
	END Open;

	(** Close a device: turn off LED and sync cache *)
	PROCEDURE Close (dev: Disks.BlockDevice; VAR res: LONGINT);
	VAR
		i: LONGINT;
	BEGIN
		WITH dev: BlockDevice DO
			(* Sync cache *)
			FOR i := 0 TO CacheSize - 1 DO
				IF dev.cache[i].active & dev.cache[i].mod THEN
					IF ~Sd.Write(dev.card, dev.cache[i].au * dev.bufferSize, dev.bufferSize * Sd.BlockSize, dev.cache[i].buffer^, 0, res) THEN RETURN END;
				END
			END;

			(* Turn LED off *)
			Sd.SetLedState(dev.card.hc, FALSE)
		END
	END Close;

	(** Reset SD card -- not implemented yet *)
	PROCEDURE Reset (dev: Disks.BlockDevice; VAR res: LONGINT);
	BEGIN
	END Reset;

	(** Get size of device *)
	PROCEDURE GetSize (dev: Disks.BlockDevice;  VAR size, res: LONGINT);
	BEGIN
			size := LONGINT(dev(BlockDevice).card.csd.capacity);
			IF size < 0 THEN size := MAX(LONGINT) END;
			res := Disks.Ok
	END GetSize;

	(** Handle messages *)
	PROCEDURE Handle (dev: Disks.BlockDevice; msg: LONGINT; par1, par2: LONGINT; VAR res: LONGINT);
	BEGIN
		res := Disks.Ok
	END Handle;

	(** Handle SD Controller Events: create & register a new disk on card insertion, remove disk on card removal *)
	PROCEDURE HandleSdEvent * (card: Sd.Card; event: LONGINT; param: ANY);
	VAR
		dev, prev: BlockDevice;
	BEGIN
		CASE event OF
			 Sd.OnInitialization:
				NEW(dev);
				InitBlockDevice(dev, card);
				INCL(dev.flags, Disks.Removable);
				Disks.Register(dev);

				INC(devId);
				dev.nextSd := devices;
				devices := dev;
				SdEnvironment.String("Disk ");
				SdEnvironment.String(dev.name);
				SdEnvironment.String(" is now available");
				SdEnvironment.Ln

			|Sd.OnRemoval:
				ASSERT(devices # NIL);
				IF devices.card = card THEN
					SdEnvironment.String("Removed disk ");
					SdEnvironment.String(devices.name);
					SdEnvironment.Ln;
					devices := devices.nextSd
				ELSE
					dev := devices;
					WHILE (dev # NIL) & (dev.card # card) DO
						prev := dev;
						dev := dev.nextSd
					END;
					ASSERT(dev # NIL);
					SdEnvironment.String("[SD] ERROR: device ");
					SdEnvironment.String(dev.name);
					SdEnvironment.String(" was removed");
					SdEnvironment.Ln;
					prev.nextSd := dev.nextSd
				END;
		END
	END HandleSdEvent;

VAR
	devId: LONGINT; (** Identifier number for next SD device *)
	devices: BlockDevice; (** List of SD block devices *)
END SdDisks.