linux/drivers/tty/serial/stm32-usart.h
Valentin Caron 9a135f16d2 serial: stm32: rework TX DMA state condition
TX DMA state condition is handled by tx_dma_busy boolean.
This boolean is set when dma descriptor is requested and reset when dma
channel is stopped (dma_terminate).

In stm32_usart_serial_remove(), stm32_usart_stop_tx() and
stm32_usart_transmit_chars_dma() fallback error case, DMA channel is
stopped but tx_dma_busy is not handled.

Rework the driver by using two new functions to solve this issue:
- stm32_usart_tx_dma_started return true if DMA TX have a descriptor.
- stm32_usart_tx_dma_enabled return true if DMAT bit is set.

stm32_usart_tx_dma_started uses tx_dma_busy flag to prevent dual DMA
transaction at the same time. This flag is set when a DMA transaction
begins and is unset when dmaengine_terminate_async function is called.
A new DMA transaction cannot be created if this flag is set.

Create a new function "stm32_usart_tx_dma_terminate" to be sure the flag
is unset after each call of dmaengine_terminate_async.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-3-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-06 15:58:46 +01:00

282 lines
7.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) Maxime Coquelin 2015
* Copyright (C) STMicroelectronics SA 2017
* Authors: Maxime Coquelin <mcoquelin.stm32@gmail.com>
* Gerald Baeza <gerald_baeza@yahoo.fr>
*/
#define DRIVER_NAME "stm32-usart"
struct stm32_usart_offsets {
u8 cr1;
u8 cr2;
u8 cr3;
u8 brr;
u8 gtpr;
u8 rtor;
u8 rqr;
u8 isr;
u8 icr;
u8 rdr;
u8 tdr;
};
struct stm32_usart_config {
u8 uart_enable_bit; /* USART_CR1_UE */
bool has_7bits_data;
bool has_swap;
bool has_wakeup;
bool has_fifo;
int fifosize;
};
struct stm32_usart_info {
struct stm32_usart_offsets ofs;
struct stm32_usart_config cfg;
};
#define UNDEF_REG 0xff
/* Register offsets */
struct stm32_usart_info stm32f4_info = {
.ofs = {
.isr = 0x00,
.rdr = 0x04,
.tdr = 0x04,
.brr = 0x08,
.cr1 = 0x0c,
.cr2 = 0x10,
.cr3 = 0x14,
.gtpr = 0x18,
.rtor = UNDEF_REG,
.rqr = UNDEF_REG,
.icr = UNDEF_REG,
},
.cfg = {
.uart_enable_bit = 13,
.has_7bits_data = false,
.fifosize = 1,
}
};
struct stm32_usart_info stm32f7_info = {
.ofs = {
.cr1 = 0x00,
.cr2 = 0x04,
.cr3 = 0x08,
.brr = 0x0c,
.gtpr = 0x10,
.rtor = 0x14,
.rqr = 0x18,
.isr = 0x1c,
.icr = 0x20,
.rdr = 0x24,
.tdr = 0x28,
},
.cfg = {
.uart_enable_bit = 0,
.has_7bits_data = true,
.has_swap = true,
.fifosize = 1,
}
};
struct stm32_usart_info stm32h7_info = {
.ofs = {
.cr1 = 0x00,
.cr2 = 0x04,
.cr3 = 0x08,
.brr = 0x0c,
.gtpr = 0x10,
.rtor = 0x14,
.rqr = 0x18,
.isr = 0x1c,
.icr = 0x20,
.rdr = 0x24,
.tdr = 0x28,
},
.cfg = {
.uart_enable_bit = 0,
.has_7bits_data = true,
.has_swap = true,
.has_wakeup = true,
.has_fifo = true,
.fifosize = 16,
}
};
/* USART_SR (F4) / USART_ISR (F7) */
#define USART_SR_PE BIT(0)
#define USART_SR_FE BIT(1)
#define USART_SR_NE BIT(2) /* F7 (NF for F4) */
#define USART_SR_ORE BIT(3)
#define USART_SR_IDLE BIT(4)
#define USART_SR_RXNE BIT(5)
#define USART_SR_TC BIT(6)
#define USART_SR_TXE BIT(7)
#define USART_SR_CTSIF BIT(9)
#define USART_SR_CTS BIT(10) /* F7 */
#define USART_SR_RTOF BIT(11) /* F7 */
#define USART_SR_EOBF BIT(12) /* F7 */
#define USART_SR_ABRE BIT(14) /* F7 */
#define USART_SR_ABRF BIT(15) /* F7 */
#define USART_SR_BUSY BIT(16) /* F7 */
#define USART_SR_CMF BIT(17) /* F7 */
#define USART_SR_SBKF BIT(18) /* F7 */
#define USART_SR_WUF BIT(20) /* H7 */
#define USART_SR_TEACK BIT(21) /* F7 */
#define USART_SR_ERR_MASK (USART_SR_ORE | USART_SR_NE | USART_SR_FE |\
USART_SR_PE)
/* Dummy bits */
#define USART_SR_DUMMY_RX BIT(16)
/* USART_DR */
#define USART_DR_MASK GENMASK(8, 0)
/* USART_BRR */
#define USART_BRR_DIV_F_MASK GENMASK(3, 0)
#define USART_BRR_DIV_M_MASK GENMASK(15, 4)
#define USART_BRR_DIV_M_SHIFT 4
#define USART_BRR_04_R_SHIFT 1
/* USART_CR1 */
#define USART_CR1_SBK BIT(0)
#define USART_CR1_RWU BIT(1) /* F4 */
#define USART_CR1_UESM BIT(1) /* H7 */
#define USART_CR1_RE BIT(2)
#define USART_CR1_TE BIT(3)
#define USART_CR1_IDLEIE BIT(4)
#define USART_CR1_RXNEIE BIT(5)
#define USART_CR1_TCIE BIT(6)
#define USART_CR1_TXEIE BIT(7)
#define USART_CR1_PEIE BIT(8)
#define USART_CR1_PS BIT(9)
#define USART_CR1_PCE BIT(10)
#define USART_CR1_WAKE BIT(11)
#define USART_CR1_M0 BIT(12) /* F7 (CR1_M for F4) */
#define USART_CR1_MME BIT(13) /* F7 */
#define USART_CR1_CMIE BIT(14) /* F7 */
#define USART_CR1_OVER8 BIT(15)
#define USART_CR1_DEDT_MASK GENMASK(20, 16) /* F7 */
#define USART_CR1_DEAT_MASK GENMASK(25, 21) /* F7 */
#define USART_CR1_RTOIE BIT(26) /* F7 */
#define USART_CR1_EOBIE BIT(27) /* F7 */
#define USART_CR1_M1 BIT(28) /* F7 */
#define USART_CR1_IE_MASK (GENMASK(8, 4) | BIT(14) | BIT(26) | BIT(27))
#define USART_CR1_FIFOEN BIT(29) /* H7 */
#define USART_CR1_DEAT_SHIFT 21
#define USART_CR1_DEDT_SHIFT 16
/* USART_CR2 */
#define USART_CR2_ADD_MASK GENMASK(3, 0) /* F4 */
#define USART_CR2_ADDM7 BIT(4) /* F7 */
#define USART_CR2_LBCL BIT(8)
#define USART_CR2_CPHA BIT(9)
#define USART_CR2_CPOL BIT(10)
#define USART_CR2_CLKEN BIT(11)
#define USART_CR2_STOP_2B BIT(13)
#define USART_CR2_STOP_MASK GENMASK(13, 12)
#define USART_CR2_LINEN BIT(14)
#define USART_CR2_SWAP BIT(15) /* F7 */
#define USART_CR2_RXINV BIT(16) /* F7 */
#define USART_CR2_TXINV BIT(17) /* F7 */
#define USART_CR2_DATAINV BIT(18) /* F7 */
#define USART_CR2_MSBFIRST BIT(19) /* F7 */
#define USART_CR2_ABREN BIT(20) /* F7 */
#define USART_CR2_ABRMOD_MASK GENMASK(22, 21) /* F7 */
#define USART_CR2_RTOEN BIT(23) /* F7 */
#define USART_CR2_ADD_F7_MASK GENMASK(31, 24) /* F7 */
/* USART_CR3 */
#define USART_CR3_EIE BIT(0)
#define USART_CR3_IREN BIT(1)
#define USART_CR3_IRLP BIT(2)
#define USART_CR3_HDSEL BIT(3)
#define USART_CR3_NACK BIT(4)
#define USART_CR3_SCEN BIT(5)
#define USART_CR3_DMAR BIT(6)
#define USART_CR3_DMAT BIT(7)
#define USART_CR3_RTSE BIT(8)
#define USART_CR3_CTSE BIT(9)
#define USART_CR3_CTSIE BIT(10)
#define USART_CR3_ONEBIT BIT(11)
#define USART_CR3_OVRDIS BIT(12) /* F7 */
#define USART_CR3_DDRE BIT(13) /* F7 */
#define USART_CR3_DEM BIT(14) /* F7 */
#define USART_CR3_DEP BIT(15) /* F7 */
#define USART_CR3_SCARCNT_MASK GENMASK(19, 17) /* F7 */
#define USART_CR3_WUS_MASK GENMASK(21, 20) /* H7 */
#define USART_CR3_WUS_START_BIT BIT(21) /* H7 */
#define USART_CR3_WUFIE BIT(22) /* H7 */
#define USART_CR3_TXFTIE BIT(23) /* H7 */
#define USART_CR3_TCBGTIE BIT(24) /* H7 */
#define USART_CR3_RXFTCFG_MASK GENMASK(27, 25) /* H7 */
#define USART_CR3_RXFTCFG_SHIFT 25 /* H7 */
#define USART_CR3_RXFTIE BIT(28) /* H7 */
#define USART_CR3_TXFTCFG_MASK GENMASK(31, 29) /* H7 */
#define USART_CR3_TXFTCFG_SHIFT 29 /* H7 */
/* USART_GTPR */
#define USART_GTPR_PSC_MASK GENMASK(7, 0)
#define USART_GTPR_GT_MASK GENMASK(15, 8)
/* USART_RTOR */
#define USART_RTOR_RTO_MASK GENMASK(23, 0) /* F7 */
#define USART_RTOR_BLEN_MASK GENMASK(31, 24) /* F7 */
/* USART_RQR */
#define USART_RQR_ABRRQ BIT(0) /* F7 */
#define USART_RQR_SBKRQ BIT(1) /* F7 */
#define USART_RQR_MMRQ BIT(2) /* F7 */
#define USART_RQR_RXFRQ BIT(3) /* F7 */
#define USART_RQR_TXFRQ BIT(4) /* F7 */
/* USART_ICR */
#define USART_ICR_PECF BIT(0) /* F7 */
#define USART_ICR_FECF BIT(1) /* F7 */
#define USART_ICR_ORECF BIT(3) /* F7 */
#define USART_ICR_IDLECF BIT(4) /* F7 */
#define USART_ICR_TCCF BIT(6) /* F7 */
#define USART_ICR_CTSCF BIT(9) /* F7 */
#define USART_ICR_RTOCF BIT(11) /* F7 */
#define USART_ICR_EOBCF BIT(12) /* F7 */
#define USART_ICR_CMCF BIT(17) /* F7 */
#define USART_ICR_WUCF BIT(20) /* H7 */
#define STM32_SERIAL_NAME "ttySTM"
#define STM32_MAX_PORTS 8
#define RX_BUF_L 4096 /* dma rx buffer length */
#define RX_BUF_P (RX_BUF_L / 2) /* dma rx buffer period */
#define TX_BUF_L RX_BUF_L /* dma tx buffer length */
struct stm32_port {
struct uart_port port;
struct clk *clk;
const struct stm32_usart_info *info;
struct dma_chan *rx_ch; /* dma rx channel */
dma_addr_t rx_dma_buf; /* dma rx buffer bus address */
unsigned char *rx_buf; /* dma rx buffer cpu address */
struct dma_chan *tx_ch; /* dma tx channel */
dma_addr_t tx_dma_buf; /* dma tx buffer bus address */
unsigned char *tx_buf; /* dma tx buffer cpu address */
u32 cr1_irq; /* USART_CR1_RXNEIE or RTOIE */
u32 cr3_irq; /* USART_CR3_RXFTIE */
int last_res;
bool tx_dma_busy; /* dma tx transaction in progress */
bool throttled; /* port throttled */
bool hw_flow_control;
bool swap; /* swap RX & TX pins */
bool fifoen;
int rxftcfg; /* RX FIFO threshold CFG */
int txftcfg; /* TX FIFO threshold CFG */
bool wakeup_src;
int rdr_mask; /* receive data register mask */
struct mctrl_gpios *gpios; /* modem control gpios */
struct dma_tx_state rx_dma_state;
};
static struct stm32_port stm32_ports[STM32_MAX_PORTS];
static struct uart_driver stm32_usart_driver;