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alistair23-linux/drivers/tty/serial/stm32-usart.h
Erwan Le Ray d0a6a7bcc3 serial: stm32: add support of RX FIFO threshold 
Adds the support of RX FIFO threshold in order to improve the RX FIFO
management.
This is done by enabling fifo threshold interrupt, instead of relying
on rx empty/fifo not full irq. That basically generates one irq/char
currently. With this patch:
- RXCFG is set to half fifo size (e.g. 16/2 = 8 data for a 16 data depth
  FIFO)
- irq rate may be reduced by up to 1/RXCFG,  e.g. 1 over 8 with current
  RXCFG setting.
- Receiver timeout is used to gather chars when FIFO threshold isn't
  reached.

Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-21 11:17:36 +02:00

281 lines
7.5 KiB
C
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// 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_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,
.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_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_NF BIT(2)
#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_FE | USART_SR_PE)
/* Dummy bits */
#define USART_SR_DUMMY_RX BIT(16)
/* USART_ICR (F7) */
#define USART_CR_TC BIT(6)
/* 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 */
/* TX FIFO threashold set to half of its depth */
#define USART_CR3_TXFTCFG_HALF 0x2
/* RX FIFO threashold set to half of its depth */
#define USART_CR3_RXFTCFG_HALF 0x2
/* 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 200 /* dma rx buffer length */
#define RX_BUF_P RX_BUF_L /* dma rx buffer period */
#define TX_BUF_L 200 /* dma tx buffer length */
struct stm32_port {
struct uart_port port;
struct clk *clk;
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 busy */
bool hw_flow_control;
bool fifoen;
int wakeirq;
int rdr_mask; /* receive data register mask */
};
static struct stm32_port stm32_ports[STM32_MAX_PORTS];
static struct uart_driver stm32_usart_driver;
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