Thanks Greg/Matt/Cris' reply. I know it's not the issue now :) > Most of the ColdFire UART blocks have no transmit FIFO, so you > are going to get 1 interrupt per character. The above block has > at least 500 characters in it (including white space). Then include > the extra command prompt and you typing (receive interrupts) and I > would figure that is going to come to around 600 interrupts. > So, yes, that seems about right. > > Check the actual character count using: > > cat /proc/tty/driver/mcf Indeed it is. The UART transmit Buffer in my board is 1 character size (no FIFO), only receiver has FIFO.
I test command "cat /proc/tty/driver/mcf", the result is as follows: [r...@freescale /]# cat /proc/tty/driver/mcf serinfo:1.0 driver revision: 0: uart:ColdFire UART mmio:0xFC060000 irq:90 tx:54821 rx:91 RTS|DTR|CD [r...@freescale /]# cat /proc/interrupts M5445X 90: 55042 UART M5445X 96: 9962 timer M5445X 99: 2 timer M5445X 100: 3761 fec(TXF) M5445X 101: 0 fec(TXB) M5445X 102: 0 fec(TXFIFO) M5445X 103: 0 fec(TXCR) M5445X 104: 8169 fec(RXF) M5445X 105: 0 fec(RXB) M5445X 106: 110 fec(MII) M5445X 107: 0 fec(LC) M5445X 108: 0 fec(HBERR) M5445X 109: 0 fec(GRA) M5445X 110: 0 fec(EBERR) M5445X 111: 0 fec(BABT) M5445X 112: 0 fec(BABR) [r...@freescale /]# cat /proc/tty/driver/mcf serinfo:1.0 driver revision: 0: uart:ColdFire UART mmio:0xFC060000 irq:90 tx:55603 rx:115 RTS|DTR|CD Thanks! Regards, Lanttor ------------------------------------------------------------------------ *From:* Greg Ungerer <g...@snapgear.com> *Sent:* 07/02/2009 8:40:49 AM +0800 *To:* uClinux development list <uclinux-dev@uclinux.org> *CC:* linux-m...@vger.kernel.org *Subject:* [uClinux-dev] uart issues on coldfire platform > Hi Lanttor, > > Lanttor wrote: >>> Hi, >>> >>> I find one issue of UART on my coldfire platforms (mcf54451evb board). >>> I use the linux-2.6.29, and use drivers/serial/mcf.c and >>> drivers/serial/serial_core.c as my uart driver source. >>> >>> Following is my test steps -- run command: cat /proc/interrupts two >>> times contiguously. >>> >>> [r...@freescale /]# cat /proc/interrupts >>> M5445X *90: 5099 UART* >>> M5445X 96: 3130 timer0 >>> M5445X 99: 0 timer3 >>> M5445X 100: 1569 fec(TXF) >>> M5445X 101: 0 fec(TXB) >>> M5445X 102: 0 fec(TXFIFO) >>> M5445X 103: 0 fec(TXCR) >>> M5445X 104: 3098 fec(RXF) >>> M5445X 105: 0 fec(RXB) >>> M5445X 106: 41 fec(MII) >>> M5445X 107: 0 fec(LC) >>> M5445X 108: 0 fec(HBERR) >>> M5445X 109: 0 fec(GRA) >>> M5445X 110: 0 fec(EBERR) >>> M5445X 111: 0 fec(BABT) >>> M5445X 112: 0 fec(BABR) >>> [r...@freescale /]# cat /proc/interrupts >>> M5445X *90: 5714 UART* >>> M5445X 96: 3700 timer0 >>> M5445X 99: 1 timer3 >>> M5445X 100: 1574 fec(TXF) >>> M5445X 101: 0 fec(TXB) >>> M5445X 102: 0 fec(TXFIFO) >>> M5445X 103: 0 fec(TXCR) >>> M5445X 104: 3108 fec(RXF) >>> M5445X 105: 0 fec(RXB) >>> M5445X 106: 47 fec(MII) >>> M5445X 107: 0 fec(LC) >>> M5445X 108: 0 fec(HBERR) >>> M5445X 109: 0 fec(GRA) >>> M5445X 110: 0 fec(EBERR) >>> M5445X 111: 0 fec(BABT) >>> M5445X 112: 0 fec(BABR) >>> >>> I find that the interrupts for above operation is 5714 - 5099 = 605 > ^^^^^^^^^^^^^ 615 ? > >>> Is it normal? (my opinion it's too much) > > Most of the ColdFire UART blocks have no transmit FIFO, so you > are going to get 1 interrupt per character. The above block has > at least 500 characters in it (including white space). Then include > the extra command prompt and you typing (receive interrupts) and I > would figure that is going to come to around 600 interrupts. > So, yes, that seems about right. > > Check the actual character count using: > > cat /proc/tty/driver/mcf > > >>> I test it on the mcf5329 board, it has the same-like result (even >>> more 605). >>> Actually I don't modify any code of mcf.c and serial_core.c, but I >>> don't >>> know why so much interrupts are occurred through one operation? > > That is the price you pay with no data FIFO's in these UART cores. > (Some of the ColdFire parts support DMA with the UART - the mcf > driver doesn't currently use this though). > > Regards > Greg > > > > ------------------------------------------------------------------------ > Greg Ungerer -- Principal Engineer EMAIL: g...@snapgear.com > SnapGear Group, McAfee PHONE: +61 7 3435 2888 > 825 Stanley St, FAX: +61 7 3891 3630 > Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com > -- > To unsubscribe from this list: send the line "unsubscribe linux-m68k" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > _______________________________________________ uClinux-dev mailing list uClinux-dev@uclinux.org http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by uclinux-dev@uclinux.org To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
