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https://github.com/AuxXxilium/arc-lkm.git
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74 lines
3.2 KiB
C
Executable File
74 lines
3.2 KiB
C
Executable File
#ifndef REDPILL_VUART_INTERNAL_H
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#define REDPILL_VUART_INTERNAL_H
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#include <linux/spinlock.h>
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#ifndef VUART_USE_TIMER_FALLBACK
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#include <linux/wait.h>
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#endif
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//Lock/unlock vdev for registries operations
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#define lock_vuart(vdev) spin_lock_irqsave((vdev)->lock, (vdev)->lock_flags);
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#define unlock_vuart(vdev) spin_unlock_irqrestore((vdev)->lock, (vdev)->lock_flags);
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//In some circumstances operations may be performed on the chip before or after the chip is initialized. If it is
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// initialized we need a lock first; otherwise we do not. This is a shortcut for this opportunistic/conditional locking.
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#define lock_vuart_oppr(vdev) if ((vdev)->initialized) { lock_vuart(vdev); }
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#define unlock_vuart_oppr(vdev) if ((vdev)->initialized) { unlock_vuart(vdev); }
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#define validate_isa_line(line) \
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if (unlikely((line) > SERIAL8250_LAST_ISA_LINE)) { \
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pr_loc_bug("%s failed - requested line %d but kernel supports only %d", __FUNCTION__, line, \
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SERIAL8250_LAST_ISA_LINE); \
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return -EINVAL; \
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}
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/**
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* An emulated 16550A chips internal state
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*
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* See http://caro.su/msx/ocm_de1/16550.pdf for details; registers are on page 9 (Table 2)
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*/
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struct serial8250_16550A_vdev {
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//Port properties
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u8 line;
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u16 iobase;
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u8 irq;
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unsigned int baud;
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//The 8250 driver port structure - it will be populated as soon as 8250 gives us the real pointer
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struct uart_port *up;
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//Chip emulated FIFOs
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struct kfifo *tx_fifo; //character to be sent (aka what we've got from the OS)
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struct kfifo *rx_fifo; //characters received (aka what we want the OS to get from us)
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//Chip registries (they're considered volatile but there's a spinlock protecting them)
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u8 rhr; //Receiver Holding Register (characters received)
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u8 thr; //Transmitter Holding Register (characters REQUESTED to be sent, TSR will contain these to be TRANSMITTED)
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u8 ier; //Interrupt Enable Register
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u8 iir; //Interrupt ID Register (same as ISR/Interrupt Status Register)
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u8 fcr; //FIFO Control Register (not really used but holds values written to it)
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u8 lcr; //Line Control Register (not really used but holds values written to it)
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u8 mcr; //Modem Control Register (used to control autoflow)
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u8 lsr; //Line Status Register
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u8 msr; //Modem Status Register
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u8 scr; //SCratch pad Register (in the original docs refered to as SPR, but linux uses SCR name)
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u8 dll; //Divisor Lat Least significant byte (not really used but holds values written to it)
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u8 dlm; //Divisor Lat Most significant byte (not really used but holds values written to it; also called DLH)
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u8 psd; //Prescaler Division (not really used but holds values written to it)
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//Some operations (e.g. FIFO access) must be locked
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bool initialized:1;
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bool registered:1; //whether the vdev is actually registered with 8250 subsystem
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spinlock_t *lock;
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unsigned long lock_flags;
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#ifndef VUART_USE_TIMER_FALLBACK
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//We emulate (i.e. self-trigger) interrupts on threads
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struct task_struct *virq_thread; //where fake interrupt code is executed
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wait_queue_head_t *virq_queue; //wait queue used to put thread to sleep
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#endif
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};
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#endif //REDPILL_VUART_INTERNAL_H
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