bsps: Move zynq-uart to bsps/shared

This moves the zynq-uart driver from bsps/arm/shared to bsps/shared to
accomodate use by AArch64 BSPs.

bsps/shared/dev/serial/zynq-uart-polled.c

@@ -0,0 +1,184 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (C) 2013, 2017 embedded brains GmbH
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <dev/serial/zynq-uart.h>
+#include <dev/serial/zynq-uart-regs.h>
+
+#include <bspopts.h>
+
+/*
+ * Make weak and let the user override.
+ */
+uint32_t zynq_uart_input_clock(void) __attribute__ ((weak));
+
+uint32_t zynq_uart_input_clock(void)
+{
+  return ZYNQ_CLOCK_UART;
+}
+
+static int zynq_cal_baud_rate(uint32_t  baudrate,
+                              uint32_t* brgr,
+                              uint32_t* bauddiv,
+                              uint32_t  modereg)
+{
+  uint32_t brgr_value;    /* Calculated value for baud rate generator */
+  uint32_t calcbaudrate;  /* Calculated baud rate */
+  uint32_t bauderror;     /* Diff between calculated and requested baud rate */
+  uint32_t best_error = 0xFFFFFFFF;
+  uint32_t percenterror;
+  uint32_t bdiv;
+  uint32_t inputclk = zynq_uart_input_clock();
+
+  /*
+   * Make sure the baud rate is not impossilby large.
+   * Fastest possible baud rate is Input Clock / 2.
+   */
+  if ((baudrate * 2) > inputclk) {
+    return -1;
+  }
+  /*
+   * Check whether the input clock is divided by 8
+   */
+  if(modereg & ZYNQ_UART_MODE_CLKS) {
+    inputclk = inputclk / 8;
+  }
+
+  /*
+   * Determine the Baud divider. It can be 4to 254.
+   * Loop through all possible combinations
+   */
+  for (bdiv = 4; bdiv < 255; bdiv++) {
+
+    /*
+     * Calculate the value for BRGR register
+     */
+    brgr_value = inputclk / (baudrate * (bdiv + 1));
+
+    /*
+     * Calculate the baud rate from the BRGR value
+     */
+    calcbaudrate = inputclk/ (brgr_value * (bdiv + 1));
+
+    /*
+     * Avoid unsigned integer underflow
+     */
+    if (baudrate > calcbaudrate) {
+      bauderror = baudrate - calcbaudrate;
+    }
+    else {
+      bauderror = calcbaudrate - baudrate;
+    }
+
+    /*
+     * Find the calculated baud rate closest to requested baud rate.
+     */
+    if (best_error > bauderror) {
+      *brgr = brgr_value;
+      *bauddiv = bdiv;
+      best_error = bauderror;
+    }
+  }
+
+  /*
+   * Make sure the best error is not too large.
+   */
+  percenterror = (best_error * 100) / baudrate;
+#define XUARTPS_MAX_BAUD_ERROR_RATE		 3	/* max % error allowed */
+  if (XUARTPS_MAX_BAUD_ERROR_RATE < percenterror) {
+    return -1;
+  }
+
+  return 0;
+}
+
+void zynq_uart_initialize(rtems_termios_device_context *base)
+{
+  zynq_uart_context *ctx = (zynq_uart_context *) base;
+  volatile zynq_uart *regs = ctx->regs;
+  uint32_t brgr = 0x3e;
+  uint32_t bauddiv = 0x6;
+
+  zynq_uart_reset_tx_flush(ctx);
+
+  zynq_cal_baud_rate(ZYNQ_UART_DEFAULT_BAUD, &brgr, &bauddiv, regs->mode);
+
+  regs->control &= ~(ZYNQ_UART_CONTROL_RXEN | ZYNQ_UART_CONTROL_TXEN);
+  regs->control = ZYNQ_UART_CONTROL_RXDIS
+    | ZYNQ_UART_CONTROL_TXDIS
+    | ZYNQ_UART_CONTROL_RXRES
+    | ZYNQ_UART_CONTROL_TXRES;
+  regs->mode = ZYNQ_UART_MODE_CHMODE(ZYNQ_UART_MODE_CHMODE_NORMAL)
+    | ZYNQ_UART_MODE_PAR(ZYNQ_UART_MODE_PAR_NONE)
+    | ZYNQ_UART_MODE_CHRL(ZYNQ_UART_MODE_CHRL_8);
+  regs->baud_rate_gen = ZYNQ_UART_BAUD_RATE_GEN_CD(brgr);
+  regs->baud_rate_div = ZYNQ_UART_BAUD_RATE_DIV_BDIV(bauddiv);
+  regs->rx_fifo_trg_lvl = ZYNQ_UART_RX_FIFO_TRG_LVL_RTRIG(0);
+  regs->rx_timeout = ZYNQ_UART_RX_TIMEOUT_RTO(0);
+  regs->control = ZYNQ_UART_CONTROL_RXEN
+    | ZYNQ_UART_CONTROL_TXEN
+    | ZYNQ_UART_CONTROL_RSTTO;
+}
+
+int zynq_uart_read_polled(rtems_termios_device_context *base)
+{
+  zynq_uart_context *ctx = (zynq_uart_context *) base;
+  volatile zynq_uart *regs = ctx->regs;
+
+  if ((regs->channel_sts & ZYNQ_UART_CHANNEL_STS_REMPTY) != 0) {
+    return -1;
+  } else {
+    return ZYNQ_UART_TX_RX_FIFO_FIFO_GET(regs->tx_rx_fifo);
+  }
+}
+
+void zynq_uart_write_polled(
+  rtems_termios_device_context *base,
+  char c
+)
+{
+  zynq_uart_context *ctx = (zynq_uart_context *) base;
+  volatile zynq_uart *regs = ctx->regs;
+
+  while ((regs->channel_sts & ZYNQ_UART_CHANNEL_STS_TFUL) != 0) {
+    /* Wait */
+  }
+
+  regs->tx_rx_fifo = ZYNQ_UART_TX_RX_FIFO_FIFO(c);
+}
+
+void zynq_uart_reset_tx_flush(zynq_uart_context *ctx)
+{
+  volatile zynq_uart *regs = ctx->regs;
+  int                 c = 4;
+
+  while (c-- > 0)
+    zynq_uart_write_polled(&ctx->base, '\r');
+
+  while ((regs->channel_sts & ZYNQ_UART_CHANNEL_STS_TEMPTY) == 0) {
+    /* Wait */
+  }
+}