gint/src/core/hardware.c

//---
//	gint:core:hardware - Platform information and hardware detection
//---

#include <gint/hardware.h>
#include <gint/defs/attributes.h>
#include <gint/defs/types.h>
#include <gint/defs/util.h>
#include <gint/mpu/pfc.h>

/* Holds information about the current platform */
GBSS uint32_t gint[HW_KEYS];

/* Processor Version Register */
#define PVR (*((volatile uint32_t *)0xff000030))
/* Product Register */
#define PRR (*((volatile uint32_t *)0xff000044))

#if defined(FX9860G) || (!defined(FX9860G) && !defined(FXCG50))

/* mpu_detect() - detect the underlying MPU
   Many thanks to Simon Lothar for relevant documentation.

   Processor Version Register (PVR) and Product Version Register (PRR) provide
   info for SH-4-based MPUS; SH-3 based boards are detected and distinguished
   by testing writable bits in the Port L Control Register (PLCR).

   Returns the detected MPU type, falling back on mpu_unknown */
GSECTION(".pretext")
static int mpu_detect(void)
{
	#define PLCR SH7705_PFC.PLCR

	/* Detect SH-3-based MPUs by testing writable bits in PLCR */
	uint16_t old = PLCR;
	PLCR = 0xffff;
	uint16_t tested = PLCR;
	PLCR = old;

	if(tested == 0x00ff) return HWMPU_SH7337;
	if(tested == 0x0fff) return HWMPU_SH7355;

	/* Check that we're dealing with an SH-4-based MPU */
	if((PVR & 0xffffff00) != 0x10300b00) return HWMPU_UNKNOWN;

	/* Tell SH-4 MPUs by testing the product version register */

	uint32_t ver = PRR & 0xfffffff0;
	if(ver == 0x00002c00) return HWMPU_SH7305;
	if(ver == 0x00002200) return HWMPU_SH7724;

	return HWMPU_UNKNOWN;
	#undef PLCR
}

/* hw_detect(): Basic hardware detection */
GSECTION(".pretext")
void hw_detect(void)
{
	gint[HWMPU] = mpu_detect();

	if(isSH4())
	{
		gint[HWCPUVR] = PVR;
		gint[HWCPUPR] = PRR;
	}

	gint[HWCALC] = HWCALC_FX9860G_SH4;
	if(gint[HWMPU] == HWMPU_SH7337 || gint[HWMPU] == HWMPU_SH7355)
	{
		gint[HWCALC] = HWCALC_FX9860G_SH3;
	}

	/* Tell Graph 35+E II from OS version (this is accurate unless someone
	   tweaks an OS file enough to de-correlate the version of the OS and
	   the version of the display and storage memory drivers, which, let's
	   be real, is enough for now.
	   TODO: Try to detect Graph 35+E II from amount of ROM in BSC? */
	char *version = (void *)0x80010020;
	if(version[1] == '3') gint[HWCALC] = HWCALC_G35PE2;

	/* Detect RAM by checking if 8804'0000 is the same as 8800'0000. */

	volatile uint8_t *R4 = (void *)0x88040000;
	volatile uint8_t *R0 = (void *)0x88000000;

	/* Make backups */
	uint8_t b0 = *R0;
	uint8_t b4 = *R4;

	/* Check if setting a different value in *R4 affects *R0. If not, then
	   we have extended RAM. */
	*R4 = ~b0;
	int ext = (*R0 == b0);

	/* Restore backups */
	*R0 = b0;
	*R4 = b4;

	gint[HWRAM]  = ext ? (512 << 10) : (256 << 10);
	/* Will be detected later on */
	gint[HWURAM] = -1;
	/* Traditionally 4 MiB, Graph 35+E II has 8 MiB */
	gint[HWROM]  = (gint[HWCALC] == HWCALC_G35PE2) ? (4 << 20) : (8 << 20);
}

#endif /* FX9860G and platform-agnostic */

#ifdef FXCG50

/* hw_detect(): Basic hardware detection */
GSECTION(".pretext")
void hw_detect(void)
{
	gint[HWMPU] = HWMPU_SH7305;
	gint[HWCPUVR] = PVR;
	gint[HWCPUPR] = PRR;

	/* Tell Prizms apart from fx-CG 50 by checking the stack address*/
	uint32_t stack;
	__asm__("mov r15, %0" : "=r"(stack));
	gint[HWCALC]  = (stack < 0x8c160000) ? HWCALC_PRIZM : HWCALC_FXCG50;

	/* Basic memory information */
	gint[HWRAM] = (2 << 20);
	gint[HWROM] = (32 << 20);
}

#endif /* FXCG50 */