晚上跟踪 了下spi_test.c,数据的传送流程大概是这样的：
transfer()(spidev_test.c)–>
ioctl()(spidev_test.c)–>
spidev_ioctl()(spidev_test.c)—>
spidev_message()(spidev.c)—>
spidev_sync()(spidev.c)—>
spi_async(spi.h)–通过调用
spi->master->transfer(spi ,message)
调用—>spi_bitbang_transfer()(spi_bitbang.c)—>
bitbang_work()(spi_bitbang.c)–
通过status=bitbang->txrx_buf()
调用—->sep4020_spi_txrx()具体的传数据，其实是 sep4020_spi_txrx()(spi_sep4020.c)与sep4020_spi_txrx()(spi_sep4020.c)共同实现的，通过硬件上的中断触发，完成了数据的传送
spidev_message()函数：
1：把用户空间的数据传进buf；
2：通过spidev_sync()函数一级级调用，来传输数据
3：把buf中的数据在送到用户空间中，通过终端显示
以下是代码运行a.out跟踪代码
# mount all………..
mount: mounting none on /proc/bus/usb failed: No such file or directory
# Starting mdev………
starting pid 358, tty '': '-/bin/sh'
hwclock: can't open '/dev/misc/rtc': No such file or directory
mkdir: cannot create directory '/var/run': File exists
/ # ./a.out
after the open———————————–
we have enter the iocontl*****************
we have enter the iocontl*****************
<7>spidev spi0.0: before the setup———1——-
<7>spidev spi0.0: —********we enter the sep4020_soi_setupxfer
<7>SPI: sep4020_spi_setupxfer: we get the clk rate is 176
<7>spidev spi0.0: setting pre-scaler to 176 (hz 500000)
<7>SPI: sep4020_spi_setupxfer: the value of div is 176
<7>SPI: sep4020_spi_setupxfer: the value of BITBANG_CS_INACTIVE is 0
<7>SPI: sep4020_spi_chipsel: we have enter the sep4020_spi_chipsel
<7>spidev spi0.0: sep4020_spi_setup: mode 0, 8 bpw, 500000 hz
<7>spidev spi0.0: spi mode 00
we have enter the iocontl*****************
we have enter the iocontl*****************
after the spi mode———————————-
we have enter the iocontl*****************
we have enter the iocontl*****************
<7>spidev spi0.0: before the setup————-3—
3333333333333333333
3333333333333333333
<7>spidev spi0.0: —********we enter the sep4020_soi_setupxfer
<7>SPI: sep4020_spi_setupxfer: we get the clk rate is 176
<7>spidev spi0.0: setting pre-scaler to 176 (hz 500000)
<7>SPI: sep4020_spi_setupxfer: the value of div is 176
<7>SPI: sep4020_spi_setupxfer: the value of BITBANG_CS_INACTIVE is 0
<7>SPI: sep4020_spi_chipsel: we have enter the sep4020_spi_chipsel
<7>spidev spi0.0: sep4020_spi_setup: mode 0, 8 bpw, 500000 hz
<7>spidev spi0.0: 8 bits per word
we have enter the iocontl*****************
we have enter the iocontl*****************
after the bits per wors—————————–
we have enter the iocontl*****************
we have enter the iocontl*****************
<7>spidev spi0.0: before the setup————-4—
<7>spidev spi0.0: —********we enter the sep4020_soi_setupxfer
<7>SPI: sep4020_spi_setupxfer: we get the clk rate is 176
<7>spidev spi0.0: setting pre-scaler to 176 (hz 500000)
<7>SPI: sep4020_spi_setupxfer: the value of div is 176
<7>SPI: sep4020_spi_setupxfer: the value of BITBANG_CS_INACTIVE is 0
<7>SPI: sep4020_spi_chipsel: we have enter the sep4020_spi_chipsel
<7>spidev spi0.0: sep4020_spi_setup: mode 0, 8 bpw, 500000 hz
<7>spidev spi0.0: 500000 Hz (max)
we have enter the iocontl*****************
we have enter the iocontl*****************
after the max speed hz———————————-
spi mode: 0
bits per word: 8
max speed: 500000 Hz (500 KHz)
before the transfer iocontl
we have enter the iocontl*****************
we have enter the iocontl*****************
<7>spidev spi0.0: default————-
——–1——–
——–1——–
———2——-
———2——-
——–3——–
——–3——–
——–4——–
——–4——–
——–5——–
——–5——–
——–6——–
——–6——–
we are in spidev_sync —–
we are in spidev_sync —–
********************spi_bitbang_transfer***********************************
********************spi_bitbang_transfer***********************************
********************spi_bitbang_transfer****************end*******************
********************spi_bitbang_transfer****************end*******************
after the spi_async
after the spi_async
1
1
2
2
*******************bitbang_work***********************************
*******************bitbang_work***********************************
bitbang_work*******1***********
bitbang_work*******1***********
we enter the sep4020_soi_setupxfer
we enter the sep4020_soi_setupxfer
<7>SPI: sep4020_spi_setupxfer: we get the clk rate is 176
<7>spidev spi0.0: setting pre-scaler to 176 (hz 500000)
<7>SPI: sep4020_spi_setupxfer: the value of div is 176
bitbang_work*******2***********
bitbang_work*******2***********
<7>SPI: sep4020_spi_chipsel: we have enter the sep4020_spi_chipsel
<7>SPI: sep4020_spi_chipsel: we have enble spi in the sep4020_spi_chipsel
bitbang_work*******3***********
bitbang_work*******3***********
bitbang_work*******4***********
bitbang_work*******4***********
<7>spidev spi0.0: txrx: tx c1c0c000, rx c1c0c000, len 38
<7>SPI: sep4020_spi_txrx: the value of SSIENR is :0x1
<7>SPI: sep4020_spi_txrx: in sep4020_spi_irq before enable spi in txrx
<7>SPI: sep4020_spi_txrx: have enble spi in txrx
<7>SPI: sep4020_spi_txrx: we begin to sent the first byte:0xff
<7>SPI: sep4020_spi_txrx: SSI_IMR:0x1e ,SSI_ISR:0x0 ,SSI_RISR:0x1 ,SSI_SR:0x2
<7>SPI: sep4020_spi_irq: I am done
<7>SPI: sep4020_spi_txrx: the read data is :0
we enter the sep4020_soi_setupxfer
we enter the sep4020_soi_setupxfer
<7>SPI: sep4020_spi_setupxfer: we get the clk rate is 176
<7>spidev spi0.0: setting pre-scaler to 176 (hz 500000)
<7>SPI: sep4020_spi_setupxfer: the value of div is 176
<7>SPI: sep4020_spi_chipsel: we have enter the sep4020_spi_chipsel
*******************bitbang_work********************end***************
*******************bitbang_work********************end***************
3
3
4
4
5
5
the end of the spidev_sync—-
the end of the spidev_sync—-
——-7——–
——-7——–
we have after the transfer iocotl———-
FF FF FF FF FF FF
40 00 00 00 00 95
FF FF FF FF FF FF
FF FF FF FF FF FF
FF FF FF FF FF FF
DE AD BE EF BA AD
BC AC
/ #
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