micropython/ports/powerpc/uart_lpc_serial.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019, Michael Neuling, IBM Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/*
* This is the LPC serial UART used by POWER9 boxes. This is modelled
* in the qemu POWER9 machine.
*/
#include <unistd.h>
#include <stdbool.h>
#include "py/mpconfig.h"
#define PROC_FREQ 50000000
#define UART_FREQ 115200
#define UART_BASE 0xc0002000
#define LPC_UART_BASE 0x60300d00103f8
/* Taken from skiboot */
#define REG_RBR 0
#define REG_THR 0
#define REG_DLL 0
#define REG_IER 1
#define REG_DLM 1
#define REG_FCR 2
#define REG_IIR 2
#define REG_LCR 3
#define REG_MCR 4
#define REG_LSR 5
#define REG_MSR 6
#define REG_SCR 7
#define LSR_DR 0x01 /* Data ready */
#define LSR_OE 0x02 /* Overrun */
#define LSR_PE 0x04 /* Parity error */
#define LSR_FE 0x08 /* Framing error */
#define LSR_BI 0x10 /* Break */
#define LSR_THRE 0x20 /* Xmit holding register empty */
#define LSR_TEMT 0x40 /* Xmitter empty */
#define LSR_ERR 0x80 /* Error */
#define LCR_DLAB 0x80 /* DLL access */
#define IER_RX 0x01
#define IER_THRE 0x02
#define IER_ALL 0x0f
static uint64_t lpc_uart_base;
static void lpc_uart_reg_write(uint64_t offset, uint8_t val) {
uint64_t addr;
addr = lpc_uart_base + offset;
*(volatile uint8_t *)addr = val;
}
static uint8_t lpc_uart_reg_read(uint64_t offset) {
uint64_t addr;
uint8_t val;
addr = lpc_uart_base + offset;
val = *(volatile uint8_t *)addr;
return val;
}
static int lpc_uart_tx_full(void) {
return !(lpc_uart_reg_read(REG_LSR) & LSR_THRE);
}
static int lpc_uart_rx_empty(void) {
return !(lpc_uart_reg_read(REG_LSR) & LSR_DR);
}
void uart_init_ppc(void) {
lpc_uart_base = LPC_UART_BASE;
}
int mp_hal_stdin_rx_chr(void) {
while (lpc_uart_rx_empty()) {
;
}
return lpc_uart_reg_read(REG_THR);
}
ports: Fix sys.stdout.buffer.write() return value. MicroPython code may rely on the return value of sys.stdout.buffer.write() to reflect the number of bytes actually written. While in most scenarios a write() operation is successful, there are cases where it fails, leading to data loss. This problem arises because, currently, write() merely returns the number of bytes it was supposed to write, without indication of failure. One scenario where write() might fail, is where USB is used and the receiving end doesn't read quickly enough to empty the receive buffer. In that case, write() on the MicroPython side can timeout, resulting in the loss of data without any indication, a behavior observed notably in communication between a Pi Pico as a client and a Linux host using the ACM driver. A complex issue arises with mp_hal_stdout_tx_strn() when it involves multiple outputs, such as USB, dupterm and hardware UART. The challenge is in handling cases where writing to one output is successful, but another fails, either fully or partially. This patch implements the following solution: mp_hal_stdout_tx_strn() attempts to write len bytes to all of the possible destinations for that data, and returns the minimum successful write length. The implementation of this is complicated by several factors: - multiple outputs may be enabled or disabled at compiled time - multiple outputs may be enabled or disabled at runtime - mp_os_dupterm_tx_strn() is one such output, optionally containing multiple additional outputs - each of these outputs may or may not be able to report success - each of these outputs may or may not be able to report partial writes As a result, there's no single strategy that fits all ports, necessitating unique logic for each instance of mp_hal_stdout_tx_strn(). Note that addressing sys.stdout.write() is more complex due to its data modification process ("cooked" output), and it remains unchanged in this patch. Developers who are concerned about accurate return values from write operations should use sys.stdout.buffer.write(). This patch might disrupt some existing code, but it's also expected to resolve issues, considering that the peculiar return value behavior of sys.stdout.buffer.write() is not well-documented and likely not widely known. Therefore, it's improbable that much existing code relies on the previous behavior. Signed-off-by: Maarten van der Schrieck <maarten@thingsconnected.nl>
2023-06-18 09:46:25 +00:00
mp_uint_t mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) {
int i;
for (i = 0; i < len; i++) {
while (lpc_uart_tx_full()) {
;
}
lpc_uart_reg_write(REG_RBR, str[i]);
}
ports: Fix sys.stdout.buffer.write() return value. MicroPython code may rely on the return value of sys.stdout.buffer.write() to reflect the number of bytes actually written. While in most scenarios a write() operation is successful, there are cases where it fails, leading to data loss. This problem arises because, currently, write() merely returns the number of bytes it was supposed to write, without indication of failure. One scenario where write() might fail, is where USB is used and the receiving end doesn't read quickly enough to empty the receive buffer. In that case, write() on the MicroPython side can timeout, resulting in the loss of data without any indication, a behavior observed notably in communication between a Pi Pico as a client and a Linux host using the ACM driver. A complex issue arises with mp_hal_stdout_tx_strn() when it involves multiple outputs, such as USB, dupterm and hardware UART. The challenge is in handling cases where writing to one output is successful, but another fails, either fully or partially. This patch implements the following solution: mp_hal_stdout_tx_strn() attempts to write len bytes to all of the possible destinations for that data, and returns the minimum successful write length. The implementation of this is complicated by several factors: - multiple outputs may be enabled or disabled at compiled time - multiple outputs may be enabled or disabled at runtime - mp_os_dupterm_tx_strn() is one such output, optionally containing multiple additional outputs - each of these outputs may or may not be able to report success - each of these outputs may or may not be able to report partial writes As a result, there's no single strategy that fits all ports, necessitating unique logic for each instance of mp_hal_stdout_tx_strn(). Note that addressing sys.stdout.write() is more complex due to its data modification process ("cooked" output), and it remains unchanged in this patch. Developers who are concerned about accurate return values from write operations should use sys.stdout.buffer.write(). This patch might disrupt some existing code, but it's also expected to resolve issues, considering that the peculiar return value behavior of sys.stdout.buffer.write() is not well-documented and likely not widely known. Therefore, it's improbable that much existing code relies on the previous behavior. Signed-off-by: Maarten van der Schrieck <maarten@thingsconnected.nl>
2023-06-18 09:46:25 +00:00
return len;
}