HI,friends,
The core frequency and bus frequency and QE frequency on MPC8360 are configed during the loading of HRCW and the CLKIN or PCI_CLKIN, in the u-boot-1.2.0, I can use the "clocks" command to show all kind of frequecy,at this time the core frequency is 528MHZ. please see follow: => clocks Clock configuration Guo Jing: Core: 528 MHz Coherent System Bus: 264 MHz QE: 396 MHz BRG: 198 MHz Local Bus Controller: 264 MHz Local Bus: 66 MHz DDR: 264 MHz DDR Secondary: 264 MHz SEC: 88 MHz I2C1: 264 MHz I2C2: 264 MHz
Then, I modified the device tree source code to make the core frequency is 660MHZ. PowerPC,8360@0 { device_type = "cpu"; reg = <0>; d-cache-line-size = <20>; // 32 bytes i-cache-line-size = <20>; // 32 bytes d-cache-size = <8000>; // L1, 32K i-cache-size = <8000>; // L1, 32K timebase-frequency = <3EF1480>; //66MHZ bus-frequency = <FBC5200>; //264MHZ clock-frequency = <2756CD00>; //660MHZ 32-bit; }; The device tree will send the core frequency information to linux kernel. Then I bootm the linux by above dtb blob. follow is the dmesg information. we can see that: time_init: decrementer frequency = 66.000000 MHz time_init: processor frequency = 660.000000 MHz
I am so confused with the core frequency. I think the dmesg show the wrong core frequency because the actual core freqyency is decided by the power on of cpu. The device tree just only send a false frequency to the linux kernel. My question is which frequency, 660MHZ or the 528MHZ, is the actual core frequency? Which one, the HRCW or the device tree, decide the actual frequency of core? If we can use the device tree to re-assign the core frequency, how this process is finished?
~ # dmesg Using MPC836x MDS machine description Linux version 2.6.22 (dpim@localhost.localdomain) (gcc version 4.0.2 20060628 (Wasabi)) #2 Mon Mar 10 01:02:46 EST 2008 Found initrd at 0xcfc39000:0xcffa4fa3 Found legacy serial port 0 for /soc8360@e0000000/serial@4500 mem=e0004500, taddr=e0004500, irq=0, clk=264000000, speed=0 Found legacy serial port 1 for /soc8360@e0000000/serial@4600 mem=e0004600, taddr=e0004600, irq=0, clk=264000000, speed=0 Entering add_active_range(0, 0, 524288) 0 entries of 256 used Found MPC83xx PCI host bridge at 0x00000000e0008500. Firmware bus number: 0->0 Bad clock source for time stamp 1 Bad clock source for time stamp 2 pio-handle not available Top of RAM: 0x80000000, Total RAM: 0x80000000 Memory hole size: 0MB Zone PFN ranges: DMA 0 -> 196608 Normal 196608 -> 196608 HighMem 196608 -> 524288 early_node_map[1] active PFN ranges 0: 0 -> 524288 On node 0 totalpages: 524288 DMA zone: 1536 pages used for memmap DMA zone: 0 pages reserved DMA zone: 195072 pages, LIFO batch:31 Normal zone: 0 pages used for memmap HighMem zone: 2560 pages used for memmap HighMem zone: 325120 pages, LIFO batch:31 Built 1 zonelists. Total pages: 520192 Kernel command line: console=ttyS0,115200 root=/dev/ram rw IPIC (128 IRQ sources) at fddf3700 QEIC (64 IRQ sources) at fddf2080 PID hash table entries: 4096 (order: 12, 16384 bytes) time_init: decrementer frequency = 66.000000 MHz time_init: processor frequency = 660.000000 MHz Dentry cache hash table entries: 131072 (order: 7, 524288 bytes) Inode-cache hash table entries: 65536 (order: 6, 262144 bytes) High memory: 1310720k Memory: 2072044k/2097152k available (2692k kernel code, 1334664k reserved, 112k data, 122k bss, 144k init) Calibrating delay loop... 131.58 BogoMIPS (lpj=263168) Mount-cache hash table entries: 512 NET: Registered protocol family 16 fsl_sec2_of_init: start PCI: Probing PCI hardware Registering qe_ic with sysfs... Registering ipic with sysfs... Generic PHY: Registered new driver SCSI subsystem initialized NET: Registered protocol family 2 IP route cache hash table entries: 32768 (order: 5, 131072 bytes) TCP established hash table entries: 131072 (order: 8, 1048576 bytes) TCP bind hash table entries: 65536 (order: 6, 262144 bytes) TCP: Hash tables configured (established 131072 bind 65536) TCP reno registered checking if image is initramfs...it isn't (no cpio magic); looks like an initrd Freeing initrd memory: 3503k freed highmem bounce pool size: 64 pages JFFS2 version 2.2. (NAND) © 2001-2006 Red Hat, Inc. cryptodev_init(c02921e8) cryptosoft: registered as device: 0 talitos: des/3des aes md5 sha1 io scheduler noop registered io scheduler anticipatory registered (default) io scheduler deadline registered io scheduler cfq registered Generic RTC Driver v1.07 WDT driver for MPC83xx initialized. mode:reset timeout=65535 (16 seconds) Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled serial8250.0: ttyS0 at MMIO 0xe0004500 (irq = 16) is a 16550A console handover: boot [udbg0] -> real [ttyS0] serial8250.0: ttyS1 at MMIO 0xe0004600 (irq = 17) is a 16550A RAMDISK driver initialized: 16 RAM disks of 32768K size 1024 blocksize loop: module loaded UCC Ethernet Controller MII Bus: probed ucc_geth: QE UCC Gigabit Ethernet Controller ucc_geth: UCC1 at 0xe0102000 (irq = 23) eth0: MTU=1500 (frame size=1518,rx_buffer_size=1536,truesize=1792,sk_buff=160) ucc_geth: UCC2 at 0xe0103000 (irq = 24) eth1: MTU=1500 (frame size=1518,rx_buffer_size=1536,truesize=1792,sk_buff=160) SKB Handler initialized(max=64) Marvell 88E1101: Registered new driver Marvell 88E1111: Registered new driver Marvell 88E1145: Registered new driver MPC8360E MDS flash device: 2000000 at fe000000 Partition number 6 MPC8360E MDS Flash Map Info: Found 1 x16 devices at 0x0 in 16-bit bank MPC8360E MDS Flash Map Info: Found an alias at 0x1000000 for the chip at 0x0 Support for command set 0001 not present gen_probe: No supported Vendor Command Set found i2c /dev entries driver ds1374 0-0068: rtc core: registered ds1374 as rtc0 TCP cubic registered NET: Registered protocol family 1 NET: Registered protocol family 17 ds1374 0-0068: setting the system clock to 1972-02-18 11:35:36 (67260936) RAMDISK: Compressed image found at block 0 VFS: Mounted root (ext2 filesystem). Freeing unused kernel memory: 144k init PHY: e0102120:00 - Link is Up - 1000/Full