From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h1T4W-0006qa-B3 for barebox@lists.infradead.org; Wed, 06 Mar 2019 09:42:48 +0000 From: Sascha Hauer Date: Wed, 6 Mar 2019 10:42:37 +0100 Message-Id: <20190306094239.29413-4-s.hauer@pengutronix.de> In-Reply-To: <20190306094239.29413-1-s.hauer@pengutronix.de> References: <20190306094239.29413-1-s.hauer@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 3/5] debug_ll: Add ns16550 early debugging functions To: Barebox List Signed-off-by: Sascha Hauer --- include/debug_ll/ns16550.h | 56 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 include/debug_ll/ns16550.h diff --git a/include/debug_ll/ns16550.h b/include/debug_ll/ns16550.h new file mode 100644 index 0000000000..7e4dbeb453 --- /dev/null +++ b/include/debug_ll/ns16550.h @@ -0,0 +1,56 @@ +#ifndef __DEBUG_LL_NS16550_H +#define __DEBUG_LL_NS16550_H + +/* + * Early debugging functions for the NS16550 + * This file needs register access functions declared as: + * + * uint8_t debug_ll_read_reg(int reg); + * void debug_ll_write_reg(int reg, uint8_t val); + */ +#define NS16550_THR 0x0 +#define NS16550_RBR 0x0 +#define NS16550_DLL 0x0 +#define NS16550_IER 0x1 +#define NS16550_DLM 0x1 +#define NS16550_FCR 0x2 +#define NS16550_LCR 0x3 +#define NS16550_MCR 0x4 +#define NS16550_LSR 0x5 + +#define NS16550_LCR_VAL 0x3 /* 8 data, 1 stop, no parity */ +#define NS16550_MCR_VAL 0x3 /* RTS/DTR */ +#define NS16550_FCR_VAL 0x7 /* Clear & enable FIFOs */ + +#define NS16550_LSR_DR 0x01 /* UART received data present */ +#define NS16550_LSR_THRE 0x20 /* Xmit holding register empty */ + +#define NS16550_LCR_BKSE 0x80 /* Bank select enable */ + +static inline void PUTC_LL(char ch) +{ + while (!(debug_ll_read_reg(NS16550_LSR) & NS16550_LSR_THRE)) + ; + + debug_ll_write_reg(NS16550_THR, ch); +} + +static inline uint16_t debug_ll_ns16550_calc_divisor(unsigned long clk) +{ + return clk / (115200 * 16); +} + +static inline void debug_ll_ns16550_init(uint16_t divisor) +{ + debug_ll_write_reg(NS16550_LCR, 0x0); /* select ier reg */ + debug_ll_write_reg(0x00, NS16550_IER); + + debug_ll_write_reg(NS16550_LCR, NS16550_LCR_BKSE); + debug_ll_write_reg(NS16550_DLL, divisor & 0xff); + debug_ll_write_reg(NS16550_DLM, (divisor >> 8) & 0xff); + debug_ll_write_reg(NS16550_LCR, NS16550_LCR_VAL); + debug_ll_write_reg(NS16550_MCR, NS16550_MCR_VAL); + debug_ll_write_reg(NS16550_FCR, NS16550_FCR_VAL); +} + +#endif -- 2.20.1 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox