SS-30 PIA IDE hard disk interface

Split out the PIA IDE hard disk interface from the swtpc09 machine. This
support appears to have been incomplete or to have bit rotten, and has been
updated and tested lightly with FLEX9.

scripts/src/bus.lua

@@ -1736,6 +1736,8 @@ if (BUSES["SS50"]~=null) then
 		MAME_DIR .. "src/devices/bus/ss50/mps2.h",
 		MAME_DIR .. "src/devices/bus/ss50/mpt.cpp",
 		MAME_DIR .. "src/devices/bus/ss50/mpt.h",
+		MAME_DIR .. "src/devices/bus/ss50/piaide.cpp",
+		MAME_DIR .. "src/devices/bus/ss50/piaide.h",
 	}
 end
 

src/devices/bus/ss50/interface.cpp

@@ -85,6 +85,7 @@
 #include "bus/ss50/mps.h"
 #include "bus/ss50/mps2.h"
 #include "bus/ss50/mpt.h"
+#include "bus/ss50/piaide.h"
 
 //**************************************************************************
 //  GLOBAL VARIABLES
@@ -225,4 +226,5 @@ void ss50_default_2rs_devices(device_slot_interface &device)
 	device.option_add("mps", SS50_MPS);
 	device.option_add("mps2", SS50_MPS2);
 	device.option_add("mpt", SS50_MPT);
+	device.option_add("piaide", SS50_PIAIDE);
 }

src/devices/bus/ss50/piaide.cpp

@@ -0,0 +1,179 @@
+// license:BSD-3-Clause
+// copyright-holders:68bit
+/**********************************************************************
+
+    PIA IDE Hard Disk Interface
+
+    Note this interface does appear to have used an 8 bit IDE data path, and
+    does appear to have discarded every second byte of storage - this does not
+    appear to be mis-implementation here. FLEX uses 256 byte sectors so half
+    of the IDE 512 byte sector give the required fit.
+
+    Some emulators appear to have stripped out that second unused byte when
+    writing their disk images. So their disk images will need to be filled
+    when importing these images for use with this device. Also some emulators
+    appear tolerant of trailing unused data and their images might need to be
+    truncated to the length defined by the disk geomentry.
+
+    The FLEX drivers for the PIA IDE appear to translate FLEX virtual track
+    and sector ID's into a target geometry. The disk geometry will likely need
+    to be defined and that can be done by using the MAME CHD disk format. The
+    range of FLEX tracks and sectors is limited to 0 to 255 so it needs to use
+    that full virtual range get the largest usable partitions. The drivers
+    support multiple partitions that appears as multiple disks to FLEX to make
+    use of more storage.
+
+    A similar (compatible) interface appears to have been used by the 'PT69'
+    SBC and drivers and disks targeting the PT69 have also run with this
+    device. The 'PT69' appears to place the PIA at 0xe010 to 0xe013 and it's
+    supporting ROM based at 0xf000, in contrast to the MAME swtpc09i machine
+    which places the PIA IDE in IO6 at 0xe060 (so that the DC5 FDC can remain
+    at IO1) and places the supporting ROM at $e800. The MAME swtpc09i machine
+    has booted some PT69 disk images with some minor software changes.
+
+**********************************************************************/
+
+#include "emu.h"
+#include "piaide.h"
+
+#include "machine/6821pia.h"
+#include "machine/idectrl.h"
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> ss50_piaide_device
+
+class ss50_piaide_device : public device_t, public ss50_card_interface
+{
+public:
+	// construction/destruction
+	ss50_piaide_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+		: device_t(mconfig, SS50_PIAIDE, tag, owner, clock)
+		, ss50_card_interface(mconfig, *this)
+		, m_pia(*this, "pia")
+		, m_ide(*this, "ide")
+	{
+	}
+
+protected:
+	// device-specific overrides
+	virtual void device_add_mconfig(machine_config &config) override;
+	virtual void device_start() override { }
+
+	// interface-specific overrides
+	virtual uint8_t register_read(offs_t offset) override;
+	virtual void register_write(offs_t offset, uint8_t data) override;
+
+private:
+	optional_device<pia6821_device> m_pia;
+	optional_device<ide_controller_device> m_ide;
+
+	uint8_t m_pia_porta;
+	uint8_t m_pia_portb;
+
+	DECLARE_READ8_MEMBER(pia_a_r);
+	DECLARE_READ8_MEMBER(pia_b_r);
+	DECLARE_WRITE8_MEMBER(pia_a_w);
+	DECLARE_WRITE8_MEMBER(pia_b_w);
+
+};
+
+//-------------------------------------------------
+//  device_add_mconfig - add device-specific
+//  machine configuration
+//-------------------------------------------------
+
+void ss50_piaide_device::device_add_mconfig(machine_config &config)
+{
+	PIA6821(config, m_pia, 0);
+	m_pia->readpa_handler().set(FUNC(ss50_piaide_device::pia_a_r));
+	m_pia->readpb_handler().set(FUNC(ss50_piaide_device::pia_b_r));
+	m_pia->writepa_handler().set(FUNC(ss50_piaide_device::pia_a_w));
+	m_pia->writepb_handler().set(FUNC(ss50_piaide_device::pia_b_w));
+
+	IDE_CONTROLLER(config, m_ide).options(ata_devices, "hdd", nullptr, false);
+}
+
+//-------------------------------------------------
+//  register_read - read from a port register
+//-------------------------------------------------
+
+uint8_t ss50_piaide_device::register_read(offs_t offset)
+{
+	return m_pia->read(offset & 3);
+}
+
+//-------------------------------------------------
+//  register_write - write to a port register
+//-------------------------------------------------
+
+void ss50_piaide_device::register_write(offs_t offset, uint8_t data)
+{
+	m_pia->write(offset & 3, data);
+}
+
+/******* MC6821 PIA on IDE Board *******/
+/* Read/Write handlers for pia ide */
+
+READ8_MEMBER( ss50_piaide_device::pia_a_r )
+{
+	return m_pia_porta;
+}
+
+READ8_MEMBER( ss50_piaide_device::pia_b_r )
+{
+	return m_pia_portb;
+}
+
+WRITE8_MEMBER( ss50_piaide_device::pia_a_w )
+{
+	m_pia_porta = data;
+}
+
+WRITE8_MEMBER( ss50_piaide_device::pia_b_w )
+{
+	uint16_t tempidedata;
+
+	m_pia_portb = data;
+
+	// Pass through a 16 bit accessor to the IDE bus.
+	uint8_t low = (data & 0x04) >> 2;
+	uint8_t high = (data & 0x18) >> 3;
+	uint16_t ide_mem_mask = low ? 0xff00 : 0x00ff;
+
+	if ((data & 0x40)&&(!(data&0x20)))  //cs0=0 cs1=1 bit 5&6
+	{
+		if (!(data & 0x02))  //rd line bit 1
+		{
+			tempidedata = m_ide->read_cs0(high, ide_mem_mask);
+			logerror("ide_bus_r: offset $%02X data %04X\n", (data&0x1c)>>2, tempidedata);
+			m_pia_porta = low ? tempidedata >> 8 : tempidedata & 0x00ff;
+		}
+		else if (!(data & 0x01))  //wr line bit 0
+		{
+			uint16_t ide_data = low ? m_pia_porta << 8: m_pia_porta;
+			m_ide->write_cs0(high, ide_data, ide_mem_mask);
+			logerror("ide_bus_w: offset $%02X data %04X\n", (data&0x1c)>>2, m_pia_porta);
+		}
+	}
+	else if ((data & 0x20)&&(!(data&0x40)))  //cs0=1 cs1=0 bit 5&6
+	{
+		if (!(data & 0x02))  //rd line bit 1
+		{
+			tempidedata = m_ide->read_cs1(high, ide_mem_mask);
+			logerror("ide_bus_r: offset $%02X data %04X\n", (data&0x1c)>>2, tempidedata);
+			m_pia_porta = low ? tempidedata >> 8 : tempidedata & 0x00ff;
+		}
+		else if (!(data & 0x01))  //wr line bit 0
+		{
+			uint16_t ide_data = low ? m_pia_porta << 8: m_pia_porta;
+			m_ide->write_cs1(high, ide_data, ide_mem_mask);
+			logerror("ide_bus_w: offset $%02X data %04X\n", (data&0x1c)>>2, m_pia_porta);
+		}
+	}
+}
+
+// device type definition
+DEFINE_DEVICE_TYPE_PRIVATE(SS50_PIAIDE, ss50_card_interface, ss50_piaide_device, "ss50_piaide", "PIA IDE Hard Disk Interface")

src/devices/bus/ss50/piaide.h

@@ -0,0 +1,15 @@
+// license:BSD-3-Clause
+// copyright-holders:68bit
+/**********************************************************************
+
+    PIA IDE Hard Disk Interface
+
+**********************************************************************/
+#ifndef MAME_DEVICE_BUS_SS50_PIAIDE_H
+#define MAME_DEVICE_BUS_SS50_PIAIDE_H
+
+#include "interface.h"
+
+DECLARE_DEVICE_TYPE(SS50_PIAIDE, ss50_card_interface)
+
+#endif // MAME_DEVICE_BUS_SS50_PIAIDE_H