linux串口驅(qū)動(dòng)分析
- 硬件資源及描寫(xiě)敘述
| 寄存器 | 名稱 | 地址 | 在linux中的描寫(xiě)敘述 ( 2410 和 2440 處理器對(duì)內(nèi)存地址映射關(guān)系同樣 ) |
| UART 線性控制寄存器（ULCONn） |
ULCON0?
ULCON1? ULCON2? |
0x50000000
0x50004000 0x50008000 |
linux-2.6.31/arch/arm/plat-s3c/include/plat/regs-serial.h
#define S3C2410_PA_UART0 ?????? ? ? (S3C24XX_PA_UART) #define S3C2410_PA_UART1 ????? ? ? (S3C24XX_PA_UART + 0x4000 ) #define S3C2410_PA_UART2 ????? ? ? (S3C24XX_PA_UART + 0x8000 ) #define S3C2443_PA_UART3????? ? ? (S3C24XX_PA_UART + 0xC000 ) linux-2.6.31/arch/arm/plat-s3c/include/plat/map.h#define S3C24XX_VA_UART??? ?? ? ? S3C_VA_UART//靜態(tài)映射后的虛擬地址 #define S3C2410_PA_UART??? ?? ? ? ( 0x50000000 )//物理地址 #define S3C24XX_SZ_UART??? ?? SZ_1M#define S3C_UART_OFFSET??? ?? ( 0x4000 ) |
| UART 控制寄存器（UCONn） |
UCON0?
UCON1 UCON2 |
0x50000004
0x50004004 0x50008004 |
#define S3C2410_UCON??? ? (0x04) |
| UART FIFO 控制寄存器(UFCONn) |
UFCON0
UFCON1 UFCON2 |
0x50000008
0x50004008 0x50008008 |
#define S3C2410_UFCON??? ? (0x08) |
| UART MODEM 控制寄存器(UMCONn) |
UMCON0
UMCON1 |
0x5000000C
0x5000400C |
#define S3C2410_UMCON??? ? (0x0C) |
| UART 接收發(fā)送狀態(tài)寄存器(UTRSTATn) |
UTRSTAT0
UTRSTAT1 UTRSTAT2 |
0x50000010
0x50004010 0x50008010 |
#define S3C2410_UTRSTAT??? ? (0x10) |
| UART 錯(cuò)誤狀態(tài)寄存器(UERSTATn) |
UERSTAT0
UERSTAT1 UERSTAT2 |
0x50000014
0x50004014 0x50008014 |
#define S3C2410_UERSTAT??? ? (0x14) |
| UART FIFO 狀態(tài)寄存器(UFSTATn) |
UFSTAT0
UFSTAT1 UFSTAT2 |
0x50000018
0x50004018 0x50008018 |
#define S3C2410_UFSTAT??? ? (0x18) |
| UART MODEM 狀態(tài)寄存器(UMSTATn) |
UFSTAT0
UFSTAT1 |
0x5000001C
0x5000401C |
#define S3C2410_UMSTAT??? ? (0x1C) |
| UART 發(fā)送緩存寄存器(UTXHn) |
UTXH0
UTXH1 UTXH2 |
0x50000020(L)
0x50000023(B) 0x50004020(L) 0x50004023(B) 0x50008020(L) 0x50008023(B) |
#define S3C2410_UTXH??? ? (0x20) |
| UART 接收緩存寄存器(URXHn) |
URXH0
URXH1 URXH2 |
0x50000024(L)
0x50000027(B) 0x50004024(L) 0x50004027(B) 0x50008024(L) 0x50008027(B) |
#define S3C2410_URXH??? ? (0x24) |
| UART 波特率除數(shù)寄存器（UBRDIVn） |
UBRDIV0
UBRDIV1 UBRDIV2 |
0x50000028
0x50004028 0x50008028 |
#define S3C2410_UBRDIV??? ? (0x28) |
| ULCON | 位 | 描寫(xiě)敘述 | 在linux中的描寫(xiě)敘述 linux-2.6.31/arch/arm/plat-s3c/include/plat/regs-serial.h |
| Reserved | [7] | ? | ? |
| Infrared Mode | [6] |
決定是否使用紅外模式
0 =正常模式操作 1 = 紅外接收發(fā)送模式 |
#define S3C2410_LCON_IRM????????? (1<<6) |
| Parity Mode | [5:3] |
在UART發(fā)送接收操作中定義奇偶碼的生成和檢
驗(yàn)類型 0xx = No parity 100 = Odd parity 101 = Even parity 110 = Parity forced/checked as 1 111 = Parity forced/checked as 0 |
#define S3C2410_LCON_PNONE??? ? (0x0)
#define S3C2410_LCON_PEVEN??? ? (0x5 << 3) #define S3C2410_LCON_PODD??? ? (0x4 << 3) #define S3C2410_LCON_PMASK??? ? (0x7 << 3) |
| Number of Stop Bit | [2] |
定義度搜按個(gè)停止位用于幀末信號(hào)
0 =每幀一個(gè)停止位 1 =每幀兩個(gè)停止位 |
#define S3C2410_LCON_STOPB??? ? (1<<2) |
| Word Length | [1:0] |
指出發(fā)送接收每幀的數(shù)據(jù)位數(shù)
00 = 5-bits 01 = 6-bits 10 = 7-bits 11 = 8-bits |
#define S3C2410_LCON_CS5??? ? (0x0)
#define S3C2410_LCON_CS6??? ? (0x1) #define S3C2410_LCON_CS7??? ? (0x2) #define S3C2410_LCON_CS8??? ? (0x3) #define S3C2410_LCON_CSMASK??? ? (0x3) |
| ? | |||
| UFCON | 位 | 描寫(xiě)敘述 | 在linux中的描寫(xiě)敘述 |
|
Tx FIFO Trigger Level |
[7:6] |
決定發(fā)送FIFO的觸發(fā)等級(jí)
00 = Empty 01 = 16-byte 10 = 32-byte 11 = 48-byte |
#define S3C2440_UFCON_TXTRIG0??? ? (0<<6)
#define S3C2440_UFCON_TXTRIG16??? ? (1<<6) #define S3C2440_UFCON_TXTRIG32??? ? (2<<6) #define S3C2440_UFCON_TXTRIG48??? ? (3<<6) |
|
Rx FIFO Trigger Level |
[5:4] |
決定接收FIFO的觸發(fā)等級(jí)
00 = 1-byte 01 = 8-byte 10 = 16-byte 11 = 32-byte |
#define S3C2440_UFCON_RXTRIG1??? ? (0<<4)
#define S3C2440_UFCON_RXTRIG8??? ? (1<<4) #define S3C2440_UFCON_RXTRIG16??? ? (2<<4) #define S3C2440_UFCON_RXTRIG32??? ? (3<<4) |
| Reserved | [3] | ? | ? |
| Tx FIFO Reset | [2] |
在重置FIFO后自己主動(dòng)清除
0 = Normal 1= Tx FIFO reset |
#define S3C2410_UFCON_RESETTX??? ? (1<<2) |
| Rx FIFO Reset | [1] |
在重置FIFO后自己主動(dòng)清除
0 = Normal 1= Rx FIFO reset |
#define S3C2410_UFCON_RESETRX??? ? (1<<1)
#define S3C2410_UFCON_RESETBOTH??? ? (3<<1) |
| FIFO Enable | [0] |
0 = Disable
1 = Enable |
? |
|
默認(rèn)設(shè)置為?
?#define S3C2410_UFCON_DEFAULT??? ? (S3C2410_UFCON_FIFOMODE | \ ??? ??? ??? ??? ?? S3C2410_UFCON_TXTRIG0? | \ ??? ??? ??? ??? ?? S3C2410_UFCON_RXTRIG8 ) |
使能FIFO Tx FIFO為空時(shí)觸發(fā)中斷 Rx FIFO中包括8個(gè)字節(jié)時(shí)觸發(fā)中斷 |
||
| ? | |||
| UFSTAT | 位 | 描寫(xiě)敘述 | 在linux中的表示 |
| Reserved | [15] | ? | ? |
|
Tx FIFO Full
|
[14] |
僅僅要在發(fā)送操作中發(fā)送FIFO滿，則自己主動(dòng)置 1。
0 = 0-byte ≤ Tx FIFO data ≤ 63-byte 1 = Full |
#define S3C2440_UFSTAT_TXFULL??? ? (1<<14) |
| Tx FIFO Count | [13:8] | 發(fā)送FIFO中的數(shù)據(jù)數(shù)量 | #define S3C2440_UFSTAT_TXSHIFT??? ? (8) |
| Reserved | [7] | ? | ? |
| Rx FIFO Full | [6] |
僅僅要在接收操作中接收FIFO滿，則自己主動(dòng)置 1。
0 = 0-byte ≤ Rx FIFO data ≤ 63-byte 1 = Full |
#define S3C2440_UFSTAT_RXFULL??? ? (1<<6) |
| Rx FIFO Count | [5:0] | 接收FIFO中的數(shù)據(jù)數(shù)量 | #define S3C2440_UFSTAT_RXSHIFT??? ? (0) |
| ? | ? | ? | ? |
- uart驅(qū)動(dòng)程序概述
| serial_core(定義): | samsumg.c (實(shí)現(xiàn))：??????????? ??????????????????????????????????????????????????????? |
|
struct
uart_driver
{
??? struct module??? ??? *owner; ??? const char??? ??? *driver_name; ??? const char??? ??? *dev_name; ??? int??? ??? ??? ?major; ??? int??? ??? ??? ?minor; ??? int??? ??? ??? ?nr; ??? struct console??? ??? *cons; ??? /* ??? ?* these are private; the low level driver should not ??? ?* touch these; they should be initialised to NULL ??? ?*/ ??? struct uart_state??? *state; ??? struct tty_driver??? *tty_driver; }; |
static struct uart_driver
s3c24xx_uart_drv
= {
??? .owner??? ??? = THIS_MODULE, ??? .dev_name??? = "s3c2410_serial",//設(shè)備名稱，這個(gè)名稱必須和 ??????? //根文件系統(tǒng)中/etc/inittab文件里的串口名稱一致 ??? .nr??? ??? = CONFIG_SERIAL_SAMSUNG_UARTS, ??? .cons??? ??? = S3C24XX_SERIAL_CONSOLE, ??? .driver_name??? = S3C24XX_SERIAL_NAME,//驅(qū)動(dòng)名稱 ??? .major??? ??? = S3C24XX_SERIAL_MAJOR, ??? .minor??? ??? = S3C24XX_SERIAL_MINOR, }; |
??? ??? uart_driver封裝了tty_driver，使底層uart驅(qū)動(dòng)不用關(guān)心ttr_driver。一個(gè)tty驅(qū)動(dòng)程序必須注冊(cè)/注銷 tty_driver，而uart驅(qū)動(dòng)則變?yōu)樽?cè)/注銷uart_driver。使用例如以下接口：
int uart_register_driver(struct uart_driver *drv);
void uart_unregister_driver(struct uart_driver *drv);
實(shí)際上，uart_register_driver()和uart_unregister_driver()中分別包括了tty_register_driver()和tty_unregister_driver()的操作。
| serial_core(定義): | samsumg.h? samsumg.c(實(shí)現(xiàn))： |
|
struct
uart_port
{
??? spinlock_t??? ??? lock;??? ??? ??? /* port lock */ ??? unsigned long??? ??? iobase;??? ??? ??? /* in/out[bwl] */ ??? unsigned char __iomem??? *membase;??? ??? /* read/write[bwl] */ ??? unsigned int??? ??? (*serial_in)(struct uart_port *, int); ??? void??? ??? ??? (*serial_out)(struct uart_port *, int, int); ??? unsigned int??? ??? irq;??? ??? ??? /* irq number */ ??? unsigned int??? ??? uartclk;??? ??? /* base uart clock */ ??? unsigned int??? ??? fifosize;??? ??? /* tx fifo size */ ??? unsigned char??? ??? x_char;??? ??? ??? /* xon/xoff char */ ??? unsigned char??? ??? regshift;??? ??? /* reg offset shift */ ??? unsigned char??? ??? iotype;??? ??? ??? /* io access style */ ??? unsigned char??? ??? unused1; #define UPIO_PORT??? ??? (0) #define UPIO_HUB6??? ??? (1) #define UPIO_MEM??? ??? (2) #define UPIO_MEM32??? ??? (3) #define UPIO_AU??? ??? ??? (4)??? ??? ??? /* Au1x00 type IO */ #define UPIO_TSI??? ??? (5)??? ??? ??? /* Tsi108/109 type IO */ #define UPIO_DWAPB??? ??? (6)??? ??? ??? /* DesignWare APB UART */ #define UPIO_RM9000??? ??? (7)??? ??? ??? /* RM9000 type IO */ ??? unsigned int??? ??? read_status_mask;??? /* driver specific */ ??? unsigned int??? ??? ignore_status_mask;??? /* driver specific */ ??? struct uart_info??? *info;??? ??? ??? /* pointer to parent info */ ??? struct uart_icount??? icount;??? ??? ??? /* statistics */ ??? struct console??? ??? *cons;??? ??? ??? /* struct console, if any */ #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ) ??? unsigned long??? ??? sysrq;??? ??? ??? /* sysrq timeout */ #endif ??? upf_t??? ??? ??? flags; #define UPF_FOURPORT??? ??? ((__force upf_t) (1 << 1)) #define UPF_SAK??? ??? ??? ((__force upf_t) (1 << 2)) #define UPF_SPD_MASK??? ??? ((__force upf_t) (0x1030)) #define UPF_SPD_HI??? ??? ((__force upf_t) (0x0010)) #define UPF_SPD_VHI??? ??? ((__force upf_t) (0x0020)) #define UPF_SPD_CUST??? ??? ((__force upf_t) (0x0030)) #define UPF_SPD_SHI??? ??? ((__force upf_t) (0x1000)) #define UPF_SPD_WARP??? ??? ((__force upf_t) (0x1010)) #define UPF_SKIP_TEST??? ??? ((__force upf_t) (1 << 6)) #define UPF_AUTO_IRQ??? ??? ((__force upf_t) (1 << 7)) #define UPF_HARDPPS_CD??? ??? ((__force upf_t) (1 << 11)) #define UPF_LOW_LATENCY??? ??? ((__force upf_t) (1 << 13)) #define UPF_BUGGY_UART??? ??? ((__force upf_t) (1 << 14)) #define UPF_NO_TXEN_TEST??? ((__force upf_t) (1 << 15)) #define UPF_MAGIC_MULTIPLIER??? ((__force upf_t) (1 << 16)) #define UPF_CONS_FLOW??? ??? ((__force upf_t) (1 << 23)) #define UPF_SHARE_IRQ??? ??? ((__force upf_t) (1 << 24)) /* The exact UART type is known and should not be probed.? */ #define UPF_FIXED_TYPE??? ??? ((__force upf_t) (1 << 27)) #define UPF_BOOT_AUTOCONF??? ((__force upf_t) (1 << 28)) #define UPF_FIXED_PORT??? ??? ((__force upf_t) (1 << 29)) #define UPF_DEAD??? ??? ((__force upf_t) (1 << 30)) #define UPF_IOREMAP??? ??? ((__force upf_t) (1 << 31)) #define UPF_CHANGE_MASK??? ??? ((__force upf_t) (0x17fff)) #define UPF_USR_MASK??? ??? ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY)) ??? unsigned int??? ??? mctrl;??? ??? ??? /* current modem ctrl settings */ ??? unsigned int??? ??? timeout;??? ??? /* character-based timeout */ ??? unsigned int??? ??? type;??? ??? ??? /* port type */ ??? const struct uart_ops??? *ops; ??? unsigned int??? ??? custom_divisor; ??? unsigned int??? ??? line;??? ??? ??? /* port index */ ??? resource_size_t??? ??? mapbase;??? ??? /* for ioremap */ ??? struct device??? ??? *dev;??? ??? ??? /* parent device */ ??? unsigned char??? ??? hub6;??? ??? ??? /* this should be in the 8250 driver */ ??? unsigned char??? ??? suspended; ??? unsigned char??? ??? unused[2]; ??? void??? ??? ??? *private_data;??? ??? /* generic platform data pointer */ }; |
struct s3c24xx_uart_port {
//
封裝了uart_port
??? unsigned char??? ??? ??? rx_claimed; ??? unsigned char??? ??? ??? tx_claimed; ??? unsigned int??? ??? ??? pm_level; ??? unsigned long??? ??? ??? baudclk_rate; ??? unsigned int??? ??? ??? rx_irq; ??? unsigned int??? ??? ??? tx_irq; ??? struct s3c24xx_uart_info??? *info; ??? struct s3c24xx_uart_clksrc??? *clksrc; ??? struct clk??? ??? ??? *clk; ??? struct clk??? ??? ??? *baudclk; ??? struct uart_port??? ??? port; #ifdef CONFIG_CPU_FREQ ??? struct notifier_block??? ??? freq_transition; #endif }; static struct s3c24xx_uart_port s3c24xx_serial_ports[ CONFIG_SERIAL_SAMSUNG_UARTS ] = { //3 uarts default ??? [0] = { ??? ??? .port = { ??? ??? ??? .lock??? ??? = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[0].port.lock), ??? ??? ??? .iotype??? ??? = UPIO_MEM, ??? ??? ??? .irq??? ??? = IRQ_S3CUART_RX0, ??? ??? ??? .uartclk??? = 0, ??? ??? ??? .fifosize??? = 16, ??? ??? ??? .ops??? ??? = &s3c24xx_serial_ops, ??? ??? ??? .flags??? ??? = UPF_BOOT_AUTOCONF, ??? ??? ??? .line??? ??? = 0, ??? ??? } ??? }, ??? [1] = { ??? ??? .port = { ??? ??? ??? .lock??? ??? = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[1].port.lock), ??? ??? ??? .iotype??? ??? = UPIO_MEM, ??? ??? ??? .irq??? ??? = IRQ_S3CUART_RX1, ??? ??? ??? .uartclk??? = 0, ??? ??? ??? .fifosize??? = 16, ??? ??? ??? .ops??? ??? = &s3c24xx_serial_ops, ??? ??? ??? .flags??? ??? = UPF_BOOT_AUTOCONF, ??? ??? ??? .line??? ??? = 1, ??? ??? } ??? }, #if CONFIG_SERIAL_SAMSUNG_UARTS > 2 ??? [2] = { ??? ??? .port = { ??? ??? ??? .lock??? ??? = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[2].port.lock), ??? ??? ??? .iotype??? ??? = UPIO_MEM, ??? ??? ??? .irq??? ??? = IRQ_S3CUART_RX2, ??? ??? ??? .uartclk??? = 0, ??? ??? ??? .fifosize??? = 16, ??? ??? ??? .ops??? ??? = &s3c24xx_serial_ops, ??? ??? ??? .flags??? ??? = UPF_BOOT_AUTOCONF, ??? ??? ??? .line??? ??? = 2, ??? ??? } ??? }, #endif #if CONFIG_SERIAL_SAMSUNG_UARTS > 3 ??? [3] = { ??? ??? .port = { ??? ??? ??? .lock??? ??? = __SPIN_LOCK_UNLOCKED(s3c24xx_serial_ports[3].port.lock), ??? ??? ??? .iotype??? ??? = UPIO_MEM, ??? ??? ??? .irq??? ??? = IRQ_S3CUART_RX3, ??? ??? ??? .uartclk??? = 0, ??? ??? ??? .fifosize??? = 16, ??? ??? ??? .ops??? ??? = &s3c24xx_serial_ops, ??? ??? ??? .flags??? ??? = UPF_BOOT_AUTOCONF, ??? ??? ??? .line??? ??? = 3, ??? ??? } ??? } #endif }; |
??? ??? uart_port用于描寫(xiě)敘述一個(gè)UARTport（直接相應(yīng)于一個(gè)串口）的I/Oport或I/O內(nèi)存地址、FIFO大小、port類型等信息。串口核心層提供例如以下函數(shù)來(lái)加入1個(gè)port：
int uart_add_one_port(struct uart_driver *drv, struct uart_port *port);
??? ??? 對(duì)上述函數(shù)的調(diào)用應(yīng)該發(fā)生在uart_register_driver()之后，uart_add_one_port()的一個(gè)最重要作用是封裝了 tty_register_device()。
?? ?? ? uart_add_one_port()的“反函數(shù)”是uart_remove_one_port()，當(dāng)中會(huì)調(diào)用tty_unregister_device()，原型為：
int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port);
| serial_core.h(定義)： | samsumg.c (實(shí)現(xiàn))：??? ??????????????????????????????????????????????????????????????????????????????????????? |
|
struct
uart_ops
{
??? unsigned int??? (*tx_empty)(struct uart_port *); ??? void??? ??? (*set_mctrl)(struct uart_port *, unsigned int mctrl); ??? unsigned int??? (*get_mctrl)(struct uart_port *); ??? void??? ??? (*stop_tx)(struct uart_port *); ??? void??? ??? (*start_tx)(struct uart_port *); ??? void??? ??? (*send_xchar)(struct uart_port *, char ch); ??? void??? ??? (*stop_rx)(struct uart_port *); ??? void??? ??? (*enable_ms)(struct uart_port *); ??? void??? ??? (*break_ctl)(struct uart_port *, int ctl); ??? int??? ??? (*startup)(struct uart_port *); ??? void??? ??? (*shutdown)(struct uart_port *); ??? void??? ??? (*flush_buffer)(struct uart_port *); ??? void??? ??? (*set_termios)(struct uart_port *, struct ktermios *new, ??? ??? ??? ??? ?????? struct ktermios *old); ??? void??? ??? (*set_ldisc)(struct uart_port *); ??? void??? ??? (*pm)(struct uart_port *, unsigned int state, ??? ??? ??? ????? unsigned int oldstate); ??? int??? ??? (*set_wake)(struct uart_port *, unsigned int state); ??? /* ??? ?* Return a string describing the type of the port ??? ?*/ ??? const char *(*type)(struct uart_port *); ??? /* ??? ?* Release IO and memory resources used by the port. ??? ?* This includes iounmap if necessary. ??? ?*/ ??? void??? ??? (*release_port)(struct uart_port *); ??? /* ??? ?* Request IO and memory resources used by the port. ??? ?* This includes iomapping the port if necessary. ??? ?*/ ??? int??? ??? (*request_port)(struct uart_port *); ??? void??? ??? (*config_port)(struct uart_port *, int); ??? int??? ??? (*verify_port)(struct uart_port *, struct serial_struct *); ??? int??? ??? (*ioctl)(struct uart_port *, unsigned int, unsigned long); #ifdef CONFIG_CONSOLE_POLL ??? void??? (*poll_put_char)(struct uart_port *, unsigned char); ??? int??? ??? (*poll_get_char)(struct uart_port *); #endif }; |
static struct uart_ops s3c24xx_serial_ops = {
??? .pm??? ??? = s3c24xx_serial_pm, ??? .tx_empty??? = s3c24xx_serial_tx_empty, ??? .get_mctrl??? = s3c24xx_serial_get_mctrl, ??? .set_mctrl??? = s3c24xx_serial_set_mctrl, ??? .stop_tx??? = s3c24xx_serial_stop_tx, ??? .start_tx??? = s3c24xx_serial_start_tx, ??? .stop_rx??? = s3c24xx_serial_stop_rx, ??? .enable_ms??? = s3c24xx_serial_enable_ms, ??? .break_ctl??? = s3c24xx_serial_break_ctl, ??? .startup??? = s3c24xx_serial_startup, ??? .shutdown??? = s3c24xx_serial_shutdown, ??? .set_termios??? = s3c24xx_serial_set_termios, ??? .type??? ??? = s3c24xx_serial_type, ??? .release_port??? = s3c24xx_serial_release_port, ??? .request_port??? = s3c24xx_serial_request_port, ??? .config_port??? = s3c24xx_serial_config_port, ??? .verify_port??? = s3c24xx_serial_verify_port, }; |
- 定義uart_driver、uart_ops、uart_port等結(jié)構(gòu)體的實(shí)例并在適當(dāng)?shù)牡胤揭罁?jù)詳細(xì)硬件和驅(qū)動(dòng)的情況初始化它們，當(dāng)然詳細(xì)設(shè)備 xxx的驅(qū)動(dòng)能夠?qū)⑦@些結(jié)構(gòu)套在新定義的xxx_uart_driver、xxx_uart_ops、xxx_uart_port之內(nèi)。
- 在模塊初始化時(shí)調(diào)用uart_register_driver()和uart_add_one_port()以注冊(cè)UART驅(qū)動(dòng)并加入端口，在模塊卸載時(shí)調(diào)用uart_unregister_driver()和uart_remove_one_port()以注銷UART驅(qū)動(dòng)并移除端口。
- ?依據(jù)詳細(xì)硬件的datasheet實(shí)現(xiàn)uart_ops中的成員函數(shù)，這些函數(shù)的實(shí)現(xiàn)成為UART驅(qū)動(dòng)的主體工作。
- 串口驅(qū)動(dòng)初始化過(guò)程
s3c2410_serial_init()→s3c24xx_serial_init()→ platform_driver_register() 的調(diào)用導(dǎo)致s3c24xx_serial_probe()被運(yùn)行，而s3c24xx_serial_probe()函數(shù)中會(huì)調(diào)用 s3c24xx_serial_init_port()初始化UART端口并調(diào)用uart_add_one_port()加入端口。
platform_device_driver 參考： Linux Platform Device and Driver ?? Linux driver model ----- platform
回過(guò)頭來(lái)看s3c24xx_uart_info結(jié)構(gòu)體（s3c24xx_uart_port的成員），是一些針對(duì)s3c2440 uart 的信息，在/drivers/serial/s3c2440.c中：
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static struct s3c24xx_uart_info s3c2440_uart_inf = {
??? .name??? ??? = "Samsung S3C2440 UART", ??? .type??? ??? = PORT_S3C2440, ??? .fifosize??? = 64, ??? .rx_fifomask??? = S3C2440_UFSTAT_RXMASK, ??? .rx_fifoshift??? = S3C2440_UFSTAT_RXSHIFT, ??? .rx_fifofull??? = S3C2440_UFSTAT_RXFULL, ??? .tx_fifofull??? = S3C2440_UFSTAT_TXFULL, ??? .tx_fifomask??? = S3C2440_UFSTAT_TXMASK, ??? .tx_fifoshift??? = S3C2440_UFSTAT_TXSHIFT, ??? .get_clksrc??? = s3c2440_serial_getsource, ??? .set_clksrc??? = s3c2440_serial_setsource, ??? .reset_port??? = s3c2440_serial_resetport, }; |
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串口操作函數(shù)，uart_ops接口函數(shù)
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static int
s3c24xx_serial_startup
(struct uart_port *port)
{ ??? struct s3c24xx_uart_port *ourport = to_ourport(port); ??? int ret; ??? dbg("s3c24xx_serial_startup: port=%p (%08lx,%p)\n", ??? ??? port->mapbase, port->membase); ??? rx_enabled(port) = 1;//接收使能 ??? ret = request_irq(ourport->rx_irq, s3c24xx_serial_rx_chars , 0, ??? ??? ??? ? s3c24xx_serial_portname(port), ourport); //申請(qǐng)接收中斷， s3c24xx_serial_rx_chars是中斷處理函數(shù) ??? if (ret != 0) { ??? ??? printk(KERN_ERR "cannot get irq %d\n", ourport->rx_irq); ??? ??? return ret; ??? } ??? ourport->rx_claimed = 1; ??? dbg("requesting tx irq...\n"); ??? tx_enabled(port) = 1;//發(fā)送使能 ??? ret = request_irq(ourport->tx_irq, s3c24xx_serial_tx_chars, 0, ??? ??? ??? ? s3c24xx_serial_portname(port), ourport); //申請(qǐng)發(fā)送中斷 ??? if (ret) { ??? ??? printk(KERN_ERR "cannot get irq %d\n", ourport->tx_irq); ??? ??? goto err; ??? } ??? ourport->tx_claimed = 1; ??? dbg("s3c24xx_serial_startup ok\n"); ??? /* the port reset code should have done the correct ??? ?* register setup for the port controls */ ??? return ret; ?err: ??? s3c24xx_serial_shutdown(port); ??? return ret; } |
s3c24xx_serial_startup()的“反函數(shù)”為s3c24xx_serial_shutdown()，其釋放中斷，禁止發(fā)送和接收。
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static void s3c24xx_serial_shutdown(struct uart_port *port)
{ ??? struct s3c24xx_uart_port *ourport = to_ourport(port); ??? if (ourport->tx_claimed) { ??? ??? free_irq(ourport->tx_irq, ourport); ??? ??? tx_enabled(port) = 0; ??? ??? ourport->tx_claimed = 0; ??? } ??? if (ourport->rx_claimed) { ??? ??? free_irq(ourport->rx_irq, ourport); ??? ??? ourport->rx_claimed = 0; ??? ??? rx_enabled(port) = 0; ??? } } |
tx_empty()成員函數(shù)s3c24xx_serial_tx_empty()用于推斷發(fā)送緩沖區(qū)是否為空，當(dāng)使能FIFO模式的時(shí)候，推斷UFSTATn寄存器，否則推斷UTRSTATn寄存器的對(duì)應(yīng)位。
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static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port)
{ ??? struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port); ??? unsigned long ufstat = rd_regl(port, S3C2410_UFSTAT); ??? unsigned long ufcon = rd_regl(port, S3C2410_UFCON); ??? if (ufcon & S3C2410_UFCON_FIFOMODE) { ??? ??? if ((ufstat & info->tx_fifomask) != 0 || ??? ??? ??? (ufstat & info->tx_fifofull)) ??? ??? ??? return 0; ??? ??? return 1; ??? } ??? return s3c24xx_serial_txempty_nofifo(port); } static int s3c24xx_serial_txempty_nofifo(struct uart_port *port) { ??? return (rd_regl(port, S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXE); } |
在samsung.h中定義了例如以下操作寄存器的宏：
/* register access controls */ #define portaddr(port, reg) ((port)->membase + (reg)) #define rd_regb(port, reg) (__raw_readb(portaddr(port, reg))) #define rd_regl(port, reg) (__raw_readl(portaddr(port, reg)))? //read regester long #define wr_regb(port, reg, val) __raw_writeb(val, portaddr(port, reg)) #define wr_regl(port, reg, val) __raw_writel(val, portaddr(port, reg)) |
start_tx ()成員函數(shù)s3c24xx_serial_start_tx()用于啟動(dòng)發(fā)送，而stop_rx()成員函數(shù) s3c24xx_serial_stop_tx()用于停止發(fā)送。
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static void s3c24xx_serial_start_tx(struct uart_port *port)
{ ??? struct s3c24xx_uart_port *ourport = to_ourport(port); ??? if (!tx_enabled(port)) { ??? ??? if (port->flags & UPF_CONS_FLOW) ??? ??? ??? s3c24xx_serial_rx_disable(port); ??? ??? enable_irq(ourport->tx_irq); ??? ??? tx_enabled(port) = 1; ??? } } |
static void s3c24xx_serial_stop_tx(struct uart_port *port)
{ ??? struct s3c24xx_uart_port *ourport = to_ourport(port); ??? if (tx_enabled(port)) { ??? ??? disable_irq_nosync(ourport->tx_irq); ??? ??? tx_enabled(port) = 0; ??? ??? if (port->flags & UPF_CONS_FLOW) ??? ??? ??? s3c24xx_serial_rx_enable(port); ??? } } |
??? ??? S3C2410 串口驅(qū)動(dòng)uart_ops結(jié)構(gòu)體的set_termios()成員函數(shù)用于改變端口的參數(shù)設(shè)置，包含波特率、字長(zhǎng)、停止位、奇偶校驗(yàn)等，它會(huì)依據(jù)傳遞給它的port、termios參數(shù)成員的值設(shè)置S3C2410 UART的ULCONn、UCONn、UMCONn等寄存器。
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static void s3c24xx_serial_set_termios(struct uart_port *port,
??? ??? ??? ??? ?????? struct ktermios *termios, ??? ??? ??? ??? ?????? struct ktermios *old) { ??? struct s3c2410_uartcfg *cfg = s3c24xx_port_to_cfg(port); ??? struct s3c24xx_uart_port *ourport = to_ourport(port); ??? struct s3c24xx_uart_clksrc *clksrc = NULL; ??? struct clk *clk = NULL; ??? unsigned long flags; ??? unsigned int baud, quot; ??? unsigned int ulcon; ??? unsigned int umcon; ??? unsigned int udivslot = 0; ??? /* ??? ?* We don't support modem control lines. ??? ?*/ ??? termios->c_cflag &= ~(HUPCL | CMSPAR); ??? termios->c_cflag |= CLOCAL; ??? /* ??? ?* Ask the core to calculate the divisor for us.請(qǐng)求內(nèi)核計(jì)算分頻以便產(chǎn)生相應(yīng)的波特率 ??? ?*/ ??? baud = uart_get_baud_rate(port, termios, old, 0, 115200*8); ??? if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) ??? ??? quot = port->custom_divisor; ??? else ??? ??? quot = s3c24xx_serial_getclk(port, &clksrc, &clk, baud); ??? /* check to see if we need? to change clock source 檢查以確定是否須要改變時(shí)鐘源 */ ??? if (ourport->clksrc != clksrc || ourport->baudclk != clk) { ??? ??? dbg("selecting clock %p\n", clk); ??? ??? s3c24xx_serial_setsource(port, clksrc); ??? ??? if (ourport->baudclk != NULL && !IS_ERR(ourport->baudclk)) { ??? ??? ??? clk_disable(ourport->baudclk); ??? ??? ??? ourport->baudclk? = NULL; ??? ??? } ??? ??? clk_enable(clk); ??? ??? ourport->clksrc = clksrc; ??? ??? ourport->baudclk = clk; ??? ??? ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0; ??? } ??? if (ourport->info->has_divslot) { ??? ??? unsigned int div = ourport->baudclk_rate / baud; ??? ??? udivslot = udivslot_table[div & 15]; ??? ??? dbg("udivslot = %04x (div %d)\n", udivslot, div & 15); ??? } ??? /* 設(shè)置字長(zhǎng) */ ??? switch (termios->c_cflag & CSIZE) { ??? case CS5: ??? ??? dbg("config: 5bits/char\n"); ??? ??? ulcon = S3C2410_LCON_CS5; ??? ??? break; ??? case CS6: ??? ??? dbg("config: 6bits/char\n"); ??? ??? ulcon = S3C2410_LCON_CS6; ??? ??? break; ??? case CS7: ??? ??? dbg("config: 7bits/char\n"); ??? ??? ulcon = S3C2410_LCON_CS7; ??? ??? break; ??? case CS8: ??? default: ??? ??? dbg("config: 8bits/char\n"); ??? ??? ulcon = S3C2410_LCON_CS8; ??? ??? break; ??? } ??? /* preserve original lcon IR settings */ ??? ulcon |= (cfg->ulcon & S3C2410_LCON_IRM); ??? if (termios->c_cflag & CSTOPB) ??? ??? ulcon |= S3C2410_LCON_STOPB; ??? umcon = (termios->c_cflag & CRTSCTS) ? S3C2410_UMCOM_AFC : 0; ??? if (termios->c_cflag & PARENB) { ??? ??? if (termios->c_cflag & PARODD) ??? ??? ??? ulcon |= S3C2410_LCON_PODD; ??? ??? else ??? ??? ??? ulcon |= S3C2410_LCON_PEVEN; ??? } else { ??? ??? ulcon |= S3C2410_LCON_PNONE; ??? } ??? spin_lock_irqsave(&port->lock, flags); ??? dbg("setting ulcon to %08x, brddiv to %d, udivslot %08x\n", ??? ??? ulcon, quot, udivslot); ??? wr_regl(port, S3C2410_ULCON, ulcon); ??? wr_regl(port, S3C2410_UBRDIV, quot); ??? wr_regl(port, S3C2410_UMCON, umcon); ??? if (ourport->info->has_divslot) ??? ??? wr_regl(port, S3C2443_DIVSLOT, udivslot); ??? dbg("uart: ulcon = 0x%08x, ucon = 0x%08x, ufcon = 0x%08x\n", ??? ??? rd_regl(port, S3C2410_ULCON), ??? ??? rd_regl(port, S3C2410_UCON), ??? ??? rd_regl(port, S3C2410_UFCON)); ??? /* ??? ?* Update the per-port timeout. ??? ?*/ ??? uart_update_timeout(port, termios->c_cflag, baud); ??? /* ??? ?* Which character status flags are we interested in? ??? ?*/ ??? port->read_status_mask = S3C2410_UERSTAT_OVERRUN; ??? if (termios->c_iflag & INPCK) ??? ??? port->read_status_mask |= S3C2410_UERSTAT_FRAME | S3C2410_UERSTAT_PARITY; ??? /* ??? ?* Which character status flags should we ignore? ??? ?*/ ??? port->ignore_status_mask = 0; ??? if (termios->c_iflag & IGNPAR) ??? ??? port->ignore_status_mask |= S3C2410_UERSTAT_OVERRUN; ??? if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR) ??? ??? port->ignore_status_mask |= S3C2410_UERSTAT_FRAME; ??? /* ??? ?* Ignore all characters if CREAD is not set. ??? ?*/ ??? if ((termios->c_cflag & CREAD) == 0) ??? ??? port->ignore_status_mask |= RXSTAT_DUMMY_READ; ??? spin_unlock_irqrestore(&port->lock, flags); } |
- 接收和發(fā)送中斷處理函數(shù)
??? ??? s3c24xx_serial_rx_chars ()讀取URXHn寄存器以獲得接收到的字符，并調(diào)用 uart_insert_char() 將該字符加入了tty設(shè)備的flip緩沖區(qū)中，當(dāng)接收到64個(gè)字符或者不再能接受到字符后，調(diào)用tty_flip_buffer_push()函數(shù)向上層“推”tty設(shè)備的flip緩沖。
??? ?? s3c24xx_serial_tx_chars()讀取uart_info中環(huán)形緩沖區(qū)中的字符，寫(xiě)入調(diào)用UTXHn寄存器。
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#define S3C2410_UERSTAT_PARITY (0x1000)
static irqreturn_t s3c24xx_serial_rx_chars (int irq, void *dev_id) { ??? struct s3c24xx_uart_port *ourport = dev_id; ??? struct uart_port *port = &ourport->port; ??? struct tty_struct *tty = port->info->port.tty; ??? unsigned int ufcon, ch, flag, ufstat, uerstat; ??? int max_count = 64; ??? while (max_count-- > 0) { ??? ??? ufcon = rd_regl(port, S3C2410_UFCON); ??? ??? ufstat = rd_regl(port, S3C2410_UFSTAT); ??? ??? if (s3c24xx_serial_rx_fifocnt(ourport, ufstat) == 0) ??? ??? ??? break; ??? ??? uerstat = rd_regl(port, S3C2410_UERSTAT); ??? ??? ch = rd_regb(port, S3C2410_URXH); ??? ??? if (port->flags & UPF_CONS_FLOW) { ??? ??? ??? int txe = s3c24xx_serial_txempty_nofifo(port); ??? ??? ??? if (rx_enabled(port)) { ??? ??? ??? ??? if (!txe) { ??? ??? ??? ??? ??? rx_enabled(port) = 0; ??? ??? ??? ??? ??? continue; ??? ??? ??? ??? } ??? ??? ??? } else { ??? ??? ??? ??? if (txe) { ??? ??? ??? ??? ??? ufcon |= S3C2410_UFCON_RESETRX; ??? ??? ??? ??? ??? wr_regl(port, S3C2410_UFCON, ufcon); ??? ??? ??? ??? ??? rx_enabled(port) = 1; ??? ??? ??? ??? ??? goto out; ??? ??? ??? ??? } ??? ??? ??? ??? continue; ??? ??? ??? } ??? ??? } ??? ??? /* insert the character into the buffer */ ??? ??? flag = TTY_NORMAL; ??? ??? port->icount.rx++; ??? ??? if (unlikely(uerstat & S3C2410_UERSTAT_ANY)) { ??? ??? ??? dbg("rxerr: port ch=0x%02x, rxs=0x%08x\n", ??? ??? ??? ??? ch, uerstat); ??? ??? ??? /* check for break */ ??? ??? ??? if (uerstat & S3C2410_UERSTAT_BREAK) { ??? ??? ??? ??? dbg("break!\n"); ??? ??? ??? ??? port->icount.brk++; ??? ??? ??? ??? if (uart_handle_break(port)) ??? ??? ??? ??? ??? goto ignore_char; ??? ??? ??? } ??? ??? ??? if (uerstat & S3C2410_UERSTAT_FRAME) ??? ??? ??? ??? port->icount.frame++; ??? ??? ??? if (uerstat & S3C2410_UERSTAT_OVERRUN) ??? ??? ??? ??? port->icount.overrun++; ??? ??? ??? uerstat &= port->read_status_mask; ??? ??? ??? if (uerstat & S3C2410_UERSTAT_BREAK) ??? ??? ??? ??? flag = TTY_BREAK; ??? ??? ??? else if (uerstat & S3C2410_UERSTAT_PARITY) ??? ??? ??? ??? flag = TTY_PARITY; ??? ??? ??? else if (uerstat & (S3C2410_UERSTAT_FRAME | ??? ??? ??? ??? ??? ??? S3C2410_UERSTAT_OVERRUN)) ??? ??? ??? ??? flag = TTY_FRAME; ??? ??? } ??? ??? if (uart_handle_sysrq_char(port, ch)) ??? ??? ??? goto ignore_char; ??? ??? uart_insert_char(port, uerstat, S3C2410_UERSTAT_OVERRUN, ??? ??? ??? ??? ?ch, flag); ?ignore_char: ??? ??? continue; ??? } ??? tty_flip_buffer_push(tty); ?out: ??? return IRQ_HANDLED; } |
static irqreturn_t s3c24xx_serial_tx_chars (int irq, void *id) { ??? struct s3c24xx_uart_port *ourport = id; ??? struct uart_port *port = &ourport->port; ??? struct circ_buf *xmit = &port->info->xmit; ??? int count = 256; ??? if (port->x_char) { ??? ??? wr_regb(port, S3C2410_UTXH, port->x_char); ??? ??? port->icount.tx++; ??? ??? port->x_char = 0; ??? ??? goto out; ??? } ??? /* if there isnt anything more to transmit, or the uart is now ??? ?* stopped, disable the uart and exit ??? */ ??? if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { ??? ??? s3c24xx_serial_stop_tx(port); ??? ??? goto out; ??? } ??? /* try and drain the buffer... */ ??? while (!uart_circ_empty(xmit) && count-- > 0) { ??? ??? if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull) ??? ??? ??? break; ??? ??? wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]); ??? ??? xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); ??? ??? port->icount.tx++; ??? } ??? if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) ??? ??? uart_write_wakeup(port); ??? if (uart_circ_empty(xmit)) ??? ??? s3c24xx_serial_stop_tx(port); ?out: ??? return IRQ_HANDLED; } |
- 串口測(cè)試
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