91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
//---
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// gint:core:mpu - Runtime MPU detection
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//---
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#include <gint/mpu.h>
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#include <gint/defs/attributes.h>
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#include <gint/defs/types.h>
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#include <gint/defs/util.h>
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/* Holds information about the current MPU */
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GBSS const platform_t gint_platform;
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/* This function is only used on fx9860g because all fxcg50 are SH4 */
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#ifdef FX9860G
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/* mpu_detect() - detect the underlying MPU
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Many thanks to Simon Lothar for relevant documentation.
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Processor Version Register (PVR) and Product Version Register (PRR) provide
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info for SH-4-based MPUS; SH-3 based boards are detected and distinguished
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by testing writable bits in the Port L Control Register (PLCR).
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Returns the detected MPU type, falling back on mpu_unknown */
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GSECTION(".pretext")
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static mpu_t mpu_detect(void)
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{
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/* Processor Version Register */
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volatile uint32_t *pvr = (void *)0xff000030;
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/* Product Version Register */
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volatile uint32_t *prr = (void *)0xff000044;
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/* Port L Control Register */
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volatile uint16_t *plcr = (void *)0xa4000114;
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/* Detecting SH-3-based MPUs by testing writable bits in PLCR */
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uint16_t old = *plcr;
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*plcr = 0xffff;
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uint16_t tested = *plcr;
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*plcr = old;
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if(tested == 0x00ff) return mpu_sh7337;
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if(tested == 0x0fff) return mpu_sh7355;
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/* Check that we're dealing with an SH-4-based MPU */
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if((*pvr & 0xffffff00) != 0x10300b00) return mpu_unknown;
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/* Tell SH-4 MPUs by testing the product version register */
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uint32_t ver = *prr & 0xfffffff0;
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if(ver == 0x00002c00) return mpu_sh7305;
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if(ver == 0x00002200) return mpu_sh7724;
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return mpu_unknown;
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}
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/* mpu_init() - detect and save information about the underlying MPU */
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GSECTION(".pretext")
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void mpu_init(GUNUSED uint32_t stack)
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{
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const_cast(gint_platform.mpu, mpu_t) = mpu_detect();
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/* Detect additional RAM */
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volatile uint8_t *after_ram = (void *)0x88040000;
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volatile uint8_t *start_ram = (void *)0x88000000;
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uint8_t backup = *after_ram;
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*after_ram = ~backup;
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int ext = (*start_ram == backup);
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*after_ram = backup;
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const_cint(gint_platform.extended_ram) = ext;
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}
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#endif /* FX9860G */
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#ifdef FXCG50
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/* mpu_init() - detect and save information about the underlying MPU */
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GSECTION(".pretext")
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void mpu_init(uint32_t stack)
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{
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const_cast(gint_platform.mpu, mpu_t) = mpu_sh7305;
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/* Detect Prizm models */
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int prizm = (stack < 0x8c160000);
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const_cint(gint_platform.prizm) = prizm;
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}
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#endif /* FXCG50 */
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