linux/drivers/tty/serial/sirfsoc_uart.h
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Drivers for CSR SiRFprimaII onboard UARTs.
   4 *
   5 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
   6 */
   7#include <linux/bitops.h>
   8#include <linux/log2.h>
   9#include <linux/hrtimer.h>
  10struct sirfsoc_uart_param {
  11        const char *uart_name;
  12        const char *port_name;
  13};
  14
  15struct sirfsoc_register {
  16        /* hardware uart specific */
  17        u32 sirfsoc_line_ctrl;
  18        u32 sirfsoc_divisor;
  19        /* uart - usp common */
  20        u32 sirfsoc_tx_rx_en;
  21        u32 sirfsoc_int_en_reg;
  22        u32 sirfsoc_int_st_reg;
  23        u32 sirfsoc_int_en_clr_reg;
  24        u32 sirfsoc_tx_dma_io_ctrl;
  25        u32 sirfsoc_tx_dma_io_len;
  26        u32 sirfsoc_tx_fifo_ctrl;
  27        u32 sirfsoc_tx_fifo_level_chk;
  28        u32 sirfsoc_tx_fifo_op;
  29        u32 sirfsoc_tx_fifo_status;
  30        u32 sirfsoc_tx_fifo_data;
  31        u32 sirfsoc_rx_dma_io_ctrl;
  32        u32 sirfsoc_rx_dma_io_len;
  33        u32 sirfsoc_rx_fifo_ctrl;
  34        u32 sirfsoc_rx_fifo_level_chk;
  35        u32 sirfsoc_rx_fifo_op;
  36        u32 sirfsoc_rx_fifo_status;
  37        u32 sirfsoc_rx_fifo_data;
  38        u32 sirfsoc_afc_ctrl;
  39        u32 sirfsoc_swh_dma_io;
  40        /* hardware usp specific */
  41        u32 sirfsoc_mode1;
  42        u32 sirfsoc_mode2;
  43        u32 sirfsoc_tx_frame_ctrl;
  44        u32 sirfsoc_rx_frame_ctrl;
  45        u32 sirfsoc_async_param_reg;
  46};
  47
  48typedef u32 (*fifo_full_mask)(struct uart_port *port);
  49typedef u32 (*fifo_empty_mask)(struct uart_port *port);
  50
  51struct sirfsoc_fifo_status {
  52        fifo_full_mask ff_full;
  53        fifo_empty_mask ff_empty;
  54};
  55
  56struct sirfsoc_int_en {
  57        u32 sirfsoc_rx_done_en;
  58        u32 sirfsoc_tx_done_en;
  59        u32 sirfsoc_rx_oflow_en;
  60        u32 sirfsoc_tx_allout_en;
  61        u32 sirfsoc_rx_io_dma_en;
  62        u32 sirfsoc_tx_io_dma_en;
  63        u32 sirfsoc_rxfifo_full_en;
  64        u32 sirfsoc_txfifo_empty_en;
  65        u32 sirfsoc_rxfifo_thd_en;
  66        u32 sirfsoc_txfifo_thd_en;
  67        u32 sirfsoc_frm_err_en;
  68        u32 sirfsoc_rxd_brk_en;
  69        u32 sirfsoc_rx_timeout_en;
  70        u32 sirfsoc_parity_err_en;
  71        u32 sirfsoc_cts_en;
  72        u32 sirfsoc_rts_en;
  73};
  74
  75struct sirfsoc_int_status {
  76        u32 sirfsoc_rx_done;
  77        u32 sirfsoc_tx_done;
  78        u32 sirfsoc_rx_oflow;
  79        u32 sirfsoc_tx_allout;
  80        u32 sirfsoc_rx_io_dma;
  81        u32 sirfsoc_tx_io_dma;
  82        u32 sirfsoc_rxfifo_full;
  83        u32 sirfsoc_txfifo_empty;
  84        u32 sirfsoc_rxfifo_thd;
  85        u32 sirfsoc_txfifo_thd;
  86        u32 sirfsoc_frm_err;
  87        u32 sirfsoc_rxd_brk;
  88        u32 sirfsoc_rx_timeout;
  89        u32 sirfsoc_parity_err;
  90        u32 sirfsoc_cts;
  91        u32 sirfsoc_rts;
  92};
  93
  94enum sirfsoc_uart_type {
  95        SIRF_REAL_UART,
  96        SIRF_USP_UART,
  97};
  98
  99struct sirfsoc_uart_register {
 100        struct sirfsoc_register uart_reg;
 101        struct sirfsoc_int_en uart_int_en;
 102        struct sirfsoc_int_status uart_int_st;
 103        struct sirfsoc_fifo_status fifo_status;
 104        struct sirfsoc_uart_param uart_param;
 105        enum sirfsoc_uart_type uart_type;
 106};
 107
 108static u32 uart_usp_ff_full_mask(struct uart_port *port)
 109{
 110        u32 full_bit;
 111
 112        full_bit = ilog2(port->fifosize);
 113        return (1 << full_bit);
 114}
 115
 116static u32 uart_usp_ff_empty_mask(struct uart_port *port)
 117{
 118        u32 empty_bit;
 119
 120        empty_bit = ilog2(port->fifosize) + 1;
 121        return (1 << empty_bit);
 122}
 123struct sirfsoc_uart_register sirfsoc_usp = {
 124        .uart_reg = {
 125                .sirfsoc_mode1          = 0x0000,
 126                .sirfsoc_mode2          = 0x0004,
 127                .sirfsoc_tx_frame_ctrl  = 0x0008,
 128                .sirfsoc_rx_frame_ctrl  = 0x000c,
 129                .sirfsoc_tx_rx_en       = 0x0010,
 130                .sirfsoc_int_en_reg     = 0x0014,
 131                .sirfsoc_int_st_reg     = 0x0018,
 132                .sirfsoc_async_param_reg = 0x0024,
 133                .sirfsoc_tx_dma_io_ctrl = 0x0100,
 134                .sirfsoc_tx_dma_io_len  = 0x0104,
 135                .sirfsoc_tx_fifo_ctrl   = 0x0108,
 136                .sirfsoc_tx_fifo_level_chk = 0x010c,
 137                .sirfsoc_tx_fifo_op     = 0x0110,
 138                .sirfsoc_tx_fifo_status = 0x0114,
 139                .sirfsoc_tx_fifo_data   = 0x0118,
 140                .sirfsoc_rx_dma_io_ctrl = 0x0120,
 141                .sirfsoc_rx_dma_io_len  = 0x0124,
 142                .sirfsoc_rx_fifo_ctrl   = 0x0128,
 143                .sirfsoc_rx_fifo_level_chk = 0x012c,
 144                .sirfsoc_rx_fifo_op     = 0x0130,
 145                .sirfsoc_rx_fifo_status = 0x0134,
 146                .sirfsoc_rx_fifo_data   = 0x0138,
 147                .sirfsoc_int_en_clr_reg = 0x140,
 148        },
 149        .uart_int_en = {
 150                .sirfsoc_rx_done_en     = BIT(0),
 151                .sirfsoc_tx_done_en     = BIT(1),
 152                .sirfsoc_rx_oflow_en    = BIT(2),
 153                .sirfsoc_tx_allout_en   = BIT(3),
 154                .sirfsoc_rx_io_dma_en   = BIT(4),
 155                .sirfsoc_tx_io_dma_en   = BIT(5),
 156                .sirfsoc_rxfifo_full_en = BIT(6),
 157                .sirfsoc_txfifo_empty_en = BIT(7),
 158                .sirfsoc_rxfifo_thd_en  = BIT(8),
 159                .sirfsoc_txfifo_thd_en  = BIT(9),
 160                .sirfsoc_frm_err_en     = BIT(10),
 161                .sirfsoc_rx_timeout_en  = BIT(11),
 162                .sirfsoc_rxd_brk_en     = BIT(15),
 163        },
 164        .uart_int_st = {
 165                .sirfsoc_rx_done        = BIT(0),
 166                .sirfsoc_tx_done        = BIT(1),
 167                .sirfsoc_rx_oflow       = BIT(2),
 168                .sirfsoc_tx_allout      = BIT(3),
 169                .sirfsoc_rx_io_dma      = BIT(4),
 170                .sirfsoc_tx_io_dma      = BIT(5),
 171                .sirfsoc_rxfifo_full    = BIT(6),
 172                .sirfsoc_txfifo_empty   = BIT(7),
 173                .sirfsoc_rxfifo_thd     = BIT(8),
 174                .sirfsoc_txfifo_thd     = BIT(9),
 175                .sirfsoc_frm_err        = BIT(10),
 176                .sirfsoc_rx_timeout     = BIT(11),
 177                .sirfsoc_rxd_brk        = BIT(15),
 178        },
 179        .fifo_status = {
 180                .ff_full                = uart_usp_ff_full_mask,
 181                .ff_empty               = uart_usp_ff_empty_mask,
 182        },
 183        .uart_param = {
 184                .uart_name = "ttySiRF",
 185                .port_name = "sirfsoc-uart",
 186        },
 187};
 188
 189struct sirfsoc_uart_register sirfsoc_uart = {
 190        .uart_reg = {
 191                .sirfsoc_line_ctrl      = 0x0040,
 192                .sirfsoc_tx_rx_en       = 0x004c,
 193                .sirfsoc_divisor        = 0x0050,
 194                .sirfsoc_int_en_reg     = 0x0054,
 195                .sirfsoc_int_st_reg     = 0x0058,
 196                .sirfsoc_int_en_clr_reg = 0x0060,
 197                .sirfsoc_tx_dma_io_ctrl = 0x0100,
 198                .sirfsoc_tx_dma_io_len  = 0x0104,
 199                .sirfsoc_tx_fifo_ctrl   = 0x0108,
 200                .sirfsoc_tx_fifo_level_chk = 0x010c,
 201                .sirfsoc_tx_fifo_op     = 0x0110,
 202                .sirfsoc_tx_fifo_status = 0x0114,
 203                .sirfsoc_tx_fifo_data   = 0x0118,
 204                .sirfsoc_rx_dma_io_ctrl = 0x0120,
 205                .sirfsoc_rx_dma_io_len  = 0x0124,
 206                .sirfsoc_rx_fifo_ctrl   = 0x0128,
 207                .sirfsoc_rx_fifo_level_chk = 0x012c,
 208                .sirfsoc_rx_fifo_op     = 0x0130,
 209                .sirfsoc_rx_fifo_status = 0x0134,
 210                .sirfsoc_rx_fifo_data   = 0x0138,
 211                .sirfsoc_afc_ctrl       = 0x0140,
 212                .sirfsoc_swh_dma_io     = 0x0148,
 213        },
 214        .uart_int_en = {
 215                .sirfsoc_rx_done_en     = BIT(0),
 216                .sirfsoc_tx_done_en     = BIT(1),
 217                .sirfsoc_rx_oflow_en    = BIT(2),
 218                .sirfsoc_tx_allout_en   = BIT(3),
 219                .sirfsoc_rx_io_dma_en   = BIT(4),
 220                .sirfsoc_tx_io_dma_en   = BIT(5),
 221                .sirfsoc_rxfifo_full_en = BIT(6),
 222                .sirfsoc_txfifo_empty_en = BIT(7),
 223                .sirfsoc_rxfifo_thd_en  = BIT(8),
 224                .sirfsoc_txfifo_thd_en  = BIT(9),
 225                .sirfsoc_frm_err_en     = BIT(10),
 226                .sirfsoc_rxd_brk_en     = BIT(11),
 227                .sirfsoc_rx_timeout_en  = BIT(12),
 228                .sirfsoc_parity_err_en  = BIT(13),
 229                .sirfsoc_cts_en         = BIT(14),
 230                .sirfsoc_rts_en         = BIT(15),
 231        },
 232        .uart_int_st = {
 233                .sirfsoc_rx_done        = BIT(0),
 234                .sirfsoc_tx_done        = BIT(1),
 235                .sirfsoc_rx_oflow       = BIT(2),
 236                .sirfsoc_tx_allout      = BIT(3),
 237                .sirfsoc_rx_io_dma      = BIT(4),
 238                .sirfsoc_tx_io_dma      = BIT(5),
 239                .sirfsoc_rxfifo_full    = BIT(6),
 240                .sirfsoc_txfifo_empty   = BIT(7),
 241                .sirfsoc_rxfifo_thd     = BIT(8),
 242                .sirfsoc_txfifo_thd     = BIT(9),
 243                .sirfsoc_frm_err        = BIT(10),
 244                .sirfsoc_rxd_brk        = BIT(11),
 245                .sirfsoc_rx_timeout     = BIT(12),
 246                .sirfsoc_parity_err     = BIT(13),
 247                .sirfsoc_cts            = BIT(14),
 248                .sirfsoc_rts            = BIT(15),
 249        },
 250        .fifo_status = {
 251                .ff_full                = uart_usp_ff_full_mask,
 252                .ff_empty               = uart_usp_ff_empty_mask,
 253        },
 254        .uart_param = {
 255                .uart_name = "ttySiRF",
 256                .port_name = "sirfsoc_uart",
 257        },
 258};
 259/* uart io ctrl */
 260#define SIRFUART_DATA_BIT_LEN_MASK              0x3
 261#define SIRFUART_DATA_BIT_LEN_5                 BIT(0)
 262#define SIRFUART_DATA_BIT_LEN_6                 1
 263#define SIRFUART_DATA_BIT_LEN_7                 2
 264#define SIRFUART_DATA_BIT_LEN_8                 3
 265#define SIRFUART_STOP_BIT_LEN_1                 0
 266#define SIRFUART_STOP_BIT_LEN_2                 BIT(2)
 267#define SIRFUART_PARITY_EN                      BIT(3)
 268#define SIRFUART_EVEN_BIT                       BIT(4)
 269#define SIRFUART_STICK_BIT_MASK                 (7 << 3)
 270#define SIRFUART_STICK_BIT_NONE                 (0 << 3)
 271#define SIRFUART_STICK_BIT_EVEN                 BIT(3)
 272#define SIRFUART_STICK_BIT_ODD                  (3 << 3)
 273#define SIRFUART_STICK_BIT_MARK                 (5 << 3)
 274#define SIRFUART_STICK_BIT_SPACE                (7 << 3)
 275#define SIRFUART_SET_BREAK                      BIT(6)
 276#define SIRFUART_LOOP_BACK                      BIT(7)
 277#define SIRFUART_PARITY_MASK                    (7 << 3)
 278#define SIRFUART_DUMMY_READ                     BIT(16)
 279#define SIRFUART_AFC_CTRL_RX_THD                0x70
 280#define SIRFUART_AFC_RX_EN                      BIT(8)
 281#define SIRFUART_AFC_TX_EN                      BIT(9)
 282#define SIRFUART_AFC_CTS_CTRL                   BIT(10)
 283#define SIRFUART_AFC_RTS_CTRL                   BIT(11)
 284#define SIRFUART_AFC_CTS_STATUS                 BIT(12)
 285#define SIRFUART_AFC_RTS_STATUS                 BIT(13)
 286/* UART FIFO Register */
 287#define SIRFUART_FIFO_STOP                      0x0
 288#define SIRFUART_FIFO_RESET                     BIT(0)
 289#define SIRFUART_FIFO_START                     BIT(1)
 290
 291#define SIRFUART_RX_EN                          BIT(0)
 292#define SIRFUART_TX_EN                          BIT(1)
 293
 294#define SIRFUART_IO_MODE                        BIT(0)
 295#define SIRFUART_DMA_MODE                       0x0
 296#define SIRFUART_RX_DMA_FLUSH                   0x4
 297
 298#define SIRFUART_CLEAR_RX_ADDR_EN               0x2
 299/* Baud Rate Calculation */
 300#define SIRF_USP_MIN_SAMPLE_DIV                 0x1
 301#define SIRF_MIN_SAMPLE_DIV                     0xf
 302#define SIRF_MAX_SAMPLE_DIV                     0x3f
 303#define SIRF_IOCLK_DIV_MAX                      0xffff
 304#define SIRF_SAMPLE_DIV_SHIFT                   16
 305#define SIRF_IOCLK_DIV_MASK                     0xffff
 306#define SIRF_SAMPLE_DIV_MASK                    0x3f0000
 307#define SIRF_BAUD_RATE_SUPPORT_NR               18
 308
 309/* USP SPEC */
 310#define SIRFSOC_USP_ENDIAN_CTRL_LSBF            BIT(4)
 311#define SIRFSOC_USP_EN                          BIT(5)
 312#define SIRFSOC_USP_MODE2_RXD_DELAY_OFFSET      0
 313#define SIRFSOC_USP_MODE2_TXD_DELAY_OFFSET      8
 314#define SIRFSOC_USP_MODE2_CLK_DIVISOR_MASK      0x3ff
 315#define SIRFSOC_USP_MODE2_CLK_DIVISOR_OFFSET    21
 316#define SIRFSOC_USP_TX_DATA_LEN_OFFSET          0
 317#define SIRFSOC_USP_TX_SYNC_LEN_OFFSET          8
 318#define SIRFSOC_USP_TX_FRAME_LEN_OFFSET         16
 319#define SIRFSOC_USP_TX_SHIFTER_LEN_OFFSET       24
 320#define SIRFSOC_USP_TX_CLK_DIVISOR_OFFSET       30
 321#define SIRFSOC_USP_RX_DATA_LEN_OFFSET          0
 322#define SIRFSOC_USP_RX_FRAME_LEN_OFFSET         8
 323#define SIRFSOC_USP_RX_SHIFTER_LEN_OFFSET       16
 324#define SIRFSOC_USP_RX_CLK_DIVISOR_OFFSET       24
 325#define SIRFSOC_USP_ASYNC_DIV2_MASK             0x3f
 326#define SIRFSOC_USP_ASYNC_DIV2_OFFSET           16
 327#define SIRFSOC_USP_LOOP_BACK_CTRL              BIT(2)
 328#define SIRFSOC_USP_FRADDR_CLR_EN               BIT(1)
 329/* USP-UART Common */
 330#define SIRFSOC_UART_RX_TIMEOUT(br, to) (((br) * (((to) + 999) / 1000)) / 1000)
 331#define SIRFUART_RECV_TIMEOUT_VALUE(x)  \
 332                                (((x) > 0xFFFF) ? 0xFFFF : ((x) & 0xFFFF))
 333#define SIRFUART_USP_RECV_TIMEOUT(x)    (x & 0xFFFF)
 334#define SIRFUART_UART_RECV_TIMEOUT(x)   ((x & 0xFFFF) << 16)
 335
 336#define SIRFUART_FIFO_THD(port)         (port->fifosize >> 1)
 337#define SIRFUART_ERR_INT_STAT(unit_st, uart_type)                       \
 338                                (uint_st->sirfsoc_rx_oflow |            \
 339                                uint_st->sirfsoc_frm_err |              \
 340                                uint_st->sirfsoc_rxd_brk |              \
 341                                ((uart_type != SIRF_REAL_UART) ? \
 342                                 0 : uint_st->sirfsoc_parity_err))
 343#define SIRFUART_RX_IO_INT_EN(uint_en, uart_type)                       \
 344                                (uint_en->sirfsoc_rx_done_en |\
 345                                 uint_en->sirfsoc_rxfifo_thd_en |\
 346                                 uint_en->sirfsoc_rxfifo_full_en |\
 347                                 uint_en->sirfsoc_frm_err_en |\
 348                                 uint_en->sirfsoc_rx_oflow_en |\
 349                                 uint_en->sirfsoc_rxd_brk_en |\
 350                                ((uart_type != SIRF_REAL_UART) ? \
 351                                 0 : uint_en->sirfsoc_parity_err_en))
 352#define SIRFUART_RX_IO_INT_ST(uint_st)                          \
 353                                (uint_st->sirfsoc_rxfifo_thd |\
 354                                 uint_st->sirfsoc_rxfifo_full|\
 355                                 uint_st->sirfsoc_rx_done |\
 356                                 uint_st->sirfsoc_rx_timeout)
 357#define SIRFUART_CTS_INT_ST(uint_st)    (uint_st->sirfsoc_cts)
 358#define SIRFUART_RX_DMA_INT_EN(uint_en, uart_type)              \
 359                                (uint_en->sirfsoc_frm_err_en |\
 360                                 uint_en->sirfsoc_rx_oflow_en |\
 361                                 uint_en->sirfsoc_rxd_brk_en |\
 362                                ((uart_type != SIRF_REAL_UART) ? \
 363                                 0 : uint_en->sirfsoc_parity_err_en))
 364/* Generic Definitions */
 365#define SIRFSOC_UART_NAME                       "ttySiRF"
 366#define SIRFSOC_UART_MAJOR                      0
 367#define SIRFSOC_UART_MINOR                      0
 368#define SIRFUART_PORT_NAME                      "sirfsoc-uart"
 369#define SIRFUART_MAP_SIZE                       0x200
 370#define SIRFSOC_UART_NR                         11
 371#define SIRFSOC_PORT_TYPE                       0xa5
 372
 373/* Uart Common Use Macro*/
 374#define SIRFSOC_RX_DMA_BUF_SIZE         (1024 * 32)
 375#define BYTES_TO_ALIGN(dma_addr)        ((unsigned long)(dma_addr) & 0x3)
 376/* Uart Fifo Level Chk */
 377#define SIRFUART_TX_FIFO_SC_OFFSET      0
 378#define SIRFUART_TX_FIFO_LC_OFFSET      10
 379#define SIRFUART_TX_FIFO_HC_OFFSET      20
 380#define SIRFUART_TX_FIFO_CHK_SC(line, value) ((((line) == 1) ? (value & 0x3) :\
 381                                (value & 0x1f)) << SIRFUART_TX_FIFO_SC_OFFSET)
 382#define SIRFUART_TX_FIFO_CHK_LC(line, value) ((((line) == 1) ? (value & 0x3) :\
 383                                (value & 0x1f)) << SIRFUART_TX_FIFO_LC_OFFSET)
 384#define SIRFUART_TX_FIFO_CHK_HC(line, value) ((((line) == 1) ? (value & 0x3) :\
 385                                (value & 0x1f)) << SIRFUART_TX_FIFO_HC_OFFSET)
 386
 387#define SIRFUART_RX_FIFO_CHK_SC SIRFUART_TX_FIFO_CHK_SC
 388#define SIRFUART_RX_FIFO_CHK_LC SIRFUART_TX_FIFO_CHK_LC
 389#define SIRFUART_RX_FIFO_CHK_HC SIRFUART_TX_FIFO_CHK_HC
 390#define SIRFUART_RX_FIFO_MASK 0x7f
 391/* Indicate how many buffers used */
 392
 393/* For Fast Baud Rate Calculation */
 394struct sirfsoc_baudrate_to_regv {
 395        unsigned int baud_rate;
 396        unsigned int reg_val;
 397};
 398
 399enum sirfsoc_tx_state {
 400        TX_DMA_IDLE,
 401        TX_DMA_RUNNING,
 402        TX_DMA_PAUSE,
 403};
 404
 405struct sirfsoc_rx_buffer {
 406        struct circ_buf                 xmit;
 407        dma_cookie_t                    cookie;
 408        struct dma_async_tx_descriptor  *desc;
 409        dma_addr_t                      dma_addr;
 410};
 411
 412struct sirfsoc_uart_port {
 413        bool                            hw_flow_ctrl;
 414        bool                            ms_enabled;
 415
 416        struct uart_port                port;
 417        struct clk                      *clk;
 418        /* for SiRFatlas7, there are SET/CLR for UART_INT_EN */
 419        bool                            is_atlas7;
 420        struct sirfsoc_uart_register    *uart_reg;
 421        struct dma_chan                 *rx_dma_chan;
 422        struct dma_chan                 *tx_dma_chan;
 423        dma_addr_t                      tx_dma_addr;
 424        struct dma_async_tx_descriptor  *tx_dma_desc;
 425        unsigned long                   transfer_size;
 426        enum sirfsoc_tx_state           tx_dma_state;
 427        unsigned int                    cts_gpio;
 428        unsigned int                    rts_gpio;
 429
 430        struct sirfsoc_rx_buffer        rx_dma_items;
 431        struct hrtimer                  hrt;
 432        bool                            is_hrt_enabled;
 433        unsigned long                   rx_period_time;
 434        unsigned long                   rx_last_pos;
 435        unsigned long                   pio_fetch_cnt;
 436};
 437
 438/* Register Access Control */
 439#define portaddr(port, reg)             ((port)->membase + (reg))
 440#define rd_regl(port, reg)              (__raw_readl(portaddr(port, reg)))
 441#define wr_regl(port, reg, val)         __raw_writel(val, portaddr(port, reg))
 442
 443/* UART Port Mask */
 444#define SIRFUART_FIFOLEVEL_MASK(port)   ((port->fifosize - 1) & 0xFFF)
 445#define SIRFUART_FIFOFULL_MASK(port)    (port->fifosize & 0xFFF)
 446#define SIRFUART_FIFOEMPTY_MASK(port)   ((port->fifosize & 0xFFF) << 1)
 447