Set CPU frequency through sysfs.

No more poking into registers via /dev/mem.
If there is no cpufreq support in the kernel, when trying to change the frequency a message will be printed on stderr that the required sysfs file cannot be opened.

src/Makefile.am

@@ -14,7 +14,7 @@ gmenu2x_SOURCES = asfont.cpp button.cpp cpu.cpp dirdialog.cpp filedialog.cpp \
 
 noinst_HEADERS = asfont.h button.h cpu.h dirdialog.h FastDelegate.h \
 	filedialog.h filelister.h gmenu2x.h gp2x.h iconbutton.h imagedialog.h \
-	inputdialog.h inputmanager.h jz4740.h linkaction.h linkapp.h link.h \
+	inputdialog.h inputmanager.h linkaction.h linkapp.h link.h \
 	menu.h menusettingbool.h menusettingdir.h \
 	menusettingfile.h menusetting.h menusettingimage.h menusettingint.h \
 	menusettingmultistring.h menusettingrgba.h menusettingstring.h \

src/cpu.cpp

@@ -1,98 +1,33 @@
-#include <stdlib.h>
-#include <stdio.h>
-#include <sys/mman.h>
-#include <unistd.h>
-#include <fcntl.h>
 #include "cpu.h"
-#include "jz4740.h"
 
-inline int sdram_convert(unsigned int pllin,unsigned int *sdram_freq)
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#define SYSFS_CPUFREQ_DIR "/sys/devices/system/cpu/cpu0/cpufreq"
+#define SYSFS_CPUFREQ_MAX SYSFS_CPUFREQ_DIR "/scaling_max_freq"
+#define SYSFS_CPUFREQ_SET SYSFS_CPUFREQ_DIR "/scaling_setspeed"
+
+void writeStringToFile(const char *path, const char *content)
 {
-	register unsigned int ns, tmp;
-
-	ns = 1000000000 / pllin;
-	/* Set refresh registers */
-	tmp = SDRAM_TREF/ns;
-	tmp = tmp/64 + 1;
-	if (tmp > 0xff) tmp = 0xff;
-	*sdram_freq = tmp;
-
-	return 0;
-
-}
-
-void pll_init(unsigned int clock)
-{
-	register unsigned int cfcr, plcr1;
-	unsigned int sdramclock = 0;
-	int n2FR[33] = {
-		0, 0, 1, 2, 3, 0, 4, 0, 5, 0, 0, 0, 6, 0, 0, 0,
-		7, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0,
-		9
-	};
-	//int div[5] = {1, 4, 4, 4, 4}; /* divisors of I:S:P:L:M */
-  	int div[5] = {1, 3, 3, 3, 3}; /* divisors of I:S:P:L:M */
-	int nf, pllout2;
-
-	cfcr = CPM_CPCCR_CLKOEN |
-		(n2FR[div[0]] << CPM_CPCCR_CDIV_BIT) |
-		(n2FR[div[1]] << CPM_CPCCR_HDIV_BIT) |
-		(n2FR[div[2]] << CPM_CPCCR_PDIV_BIT) |
-		(n2FR[div[3]] << CPM_CPCCR_MDIV_BIT) |
-		(n2FR[div[4]] << CPM_CPCCR_LDIV_BIT);
-
-	pllout2 = (cfcr & CPM_CPCCR_PCS) ? clock : (clock / 2);
-
-	/* Init UHC clock */
-//	REG_CPM_UHCCDR = pllout2 / 48000000 - 1;
-    	jz_cpmregl[0x6C>>2] = pllout2 / 48000000 - 1;
-
-	nf = clock * 2 / CFG_EXTAL;
-	plcr1 = ((nf - 2) << CPM_CPPCR_PLLM_BIT) | /* FD */
-		(0 << CPM_CPPCR_PLLN_BIT) |	/* RD=0, NR=2 */
-		(0 << CPM_CPPCR_PLLOD_BIT) |    /* OD=0, NO=1 */
-		(0x20 << CPM_CPPCR_PLLST_BIT) | /* PLL stable time */
-		CPM_CPPCR_PLLEN;                /* enable PLL */
-
-	/* init PLL */
-//	REG_CPM_CPCCR = cfcr;
-//	REG_CPM_CPPCR = plcr1;
-      	jz_cpmregl[0] = cfcr;
-    	jz_cpmregl[0x10>>2] = plcr1;
-
-  	sdram_convert(clock,&sdramclock);
-  	if(sdramclock > 0)
-  	{
-//	REG_EMC_RTCOR = sdramclock;
-//	REG_EMC_RTCNT = sdramclock;
-      	jz_emcregs[0x8C>>1] = sdramclock;
-    	jz_emcregs[0x88>>1] = sdramclock;
-
-  	}else
-  	{
-  	printf("sdram init fail!\n");
-  	while(1) {}
+	int fd = open(path, O_RDWR);
+	if (fd == -1) {
+		fprintf(stderr, "Failed to open \"%s\": %s\n", path, strerror(errno));
+	} else {
+		ssize_t written = write(fd, content, strlen(content));
+		if (written == -1) {
+			fprintf(stderr, "Error writing \"%s\": %s\n", path, strerror(errno));
+		}
+		close(fd);
 	}
-
 }
 
-
 void jz_cpuspeed(unsigned clockspeed)
 {
-	if (clockspeed >= 200 && clockspeed <= 430)
-	{
-		jz_dev = open("/dev/mem", O_RDWR);
-		if(jz_dev)
-		{
-			jz_cpmregl=(unsigned long  *)mmap(0, 0x80, PROT_READ|PROT_WRITE, MAP_SHARED, jz_dev, 0x10000000);
-			jz_emcregl=(unsigned long  *)mmap(0, 0x90, PROT_READ|PROT_WRITE, MAP_SHARED, jz_dev, 0x13010000);
-			jz_emcregs=(unsigned short *)jz_emcregl;
-			pll_init(clockspeed*1000000);
-			munmap((void *)jz_cpmregl, 0x80);
-			munmap((void *)jz_emcregl, 0x90);
-			close(jz_dev);
-		}
-		else
-			printf("failed opening /dev/mem \n");
-	}
+	char freq[10];
+	sprintf(freq, "%d", clockspeed * 1000);
+	writeStringToFile(SYSFS_CPUFREQ_MAX, freq);
+	writeStringToFile(SYSFS_CPUFREQ_SET, freq);
 }

src/cpu.h

@@ -1,24 +1,6 @@
 #ifndef CPU_H
 #define CPU_H
 
-/* Define this to the CPU frequency */
-#define CPU_FREQ 336000000    /* CPU clock: 336 MHz */
-#define CFG_EXTAL 12000000    /* EXT clock: 12 Mhz */
-
-// SDRAM Timings, unit: ns
-#define SDRAM_TRAS		45	/* RAS# Active Time */
-#define SDRAM_RCD		20	/* RAS# to CAS# Delay */
-#define SDRAM_TPC		20	/* RAS# Precharge Time */
-#define SDRAM_TRWL		7	/* Write Latency Time */
-#define SDRAM_TREF	        15625	/* Refresh period: 4096 refresh cycles/64ms */
-//#define SDRAM_TREF      7812  /* Refresh period: 8192 refresh cycles/64ms */
-
-static unsigned long jz_dev;
-static volatile unsigned long  *jz_cpmregl, *jz_emcregl;
-volatile unsigned short *jz_emcregs;
-
 void jz_cpuspeed(unsigned clockspeed);
-void pll_init(unsigned int clock);
-inline int sdram_convert(unsigned int pllin,unsigned int *sdram_freq);
 
 #endif

src/gmenu2x.cpp

@@ -526,8 +526,8 @@ void GMenu2X::readConfig() {
 	if (confStr["skin"].empty() || !fileExists("skins/"+confStr["skin"])) confStr["skin"] = "Default";
 
 	evalIntConf( &confInt["outputLogs"], 0, 0,1 );
-	evalIntConf( &confInt["maxClock"], 430, 200,430 );
-	evalIntConf( &confInt["menuClock"], 200, 200,430 );
+	evalIntConf( &confInt["maxClock"], 430, 30, 500 );
+	evalIntConf( &confInt["menuClock"], 200, 30, 430 );
 	evalIntConf( &confInt["globalVolume"], 67, 0,100 );
 	evalIntConf( &confInt["backlight"], 100, 5,100 );
 	evalIntConf( &confInt["videoBpp"], 32,32,32 ); // 8,16
@@ -1799,20 +1799,9 @@ void GMenu2X::applyDefaultTimings() {
 
 
 void GMenu2X::setClock(unsigned mhz) {
-	mhz = constrain(mhz,200,confInt["maxClock"]);
+	mhz = constrain(mhz, 30, confInt["maxClock"]);
 #ifdef TARGET_GP2X
-/*	if (gp2x_mem!=0) {
-		unsigned v;
-		unsigned mdiv,pdiv=3,scale=0;
-		mhz*=1000000;
-		mdiv=(mhz*pdiv)/GP2X_CLK_FREQ;
-		mdiv=((mdiv-8)<<8) & 0xff00;
-		pdiv=((pdiv-2)<<2) & 0xfc;
-		scale&=3;
-		v=mdiv | pdiv | scale;
-		MEM_REG[0x910>>1]=v;
-	}*/
-	/*jz_cpuspeed(mhz);*/
+	jz_cpuspeed(mhz);
 #endif
 }