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Message-ID: <20240319095315.27624-13-jirislaby@kernel.org>
Date: Tue, 19 Mar 2024 10:53:11 +0100
From: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To: linux-serial@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
"Jiri Slaby (SUSE)" <jirislaby@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
linux-arm-msm@...r.kernel.org
Subject: [RFT 11/15] tty: msm_serial: use dmaengine_prep_slave_sg()
This is a preparatory for the serial-to-kfifo switch. kfifo understands
only scatter-gatter approach, so switch to that.
No functional change intended, it's just dmaengine_prep_slave_single()
inline expanded.
And in this case, switch from dma_map_single() to dma_map_sg() too. This
needs struct msm_dma changes. I split the rx and tx parts into an union.
TX is now struct scatterlist, RX remains the old good phys-virt-count
triple.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
Cc: Bjorn Andersson <andersson@...nel.org>
Cc: Konrad Dybcio <konrad.dybcio@...aro.org>
Cc: linux-arm-msm@...r.kernel.org
---
drivers/tty/serial/msm_serial.c | 86 +++++++++++++++++++--------------
1 file changed, 49 insertions(+), 37 deletions(-)
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index d27c4c8c84e1..7bf30e632313 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -161,11 +161,16 @@ enum {
struct msm_dma {
struct dma_chan *chan;
enum dma_data_direction dir;
- dma_addr_t phys;
- unsigned char *virt;
+ union {
+ struct {
+ dma_addr_t phys;
+ unsigned char *virt;
+ unsigned int count;
+ } rx;
+ struct scatterlist tx_sg;
+ };
dma_cookie_t cookie;
u32 enable_bit;
- unsigned int count;
struct dma_async_tx_descriptor *desc;
};
@@ -249,8 +254,12 @@ static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
unsigned int mapped;
u32 val;
- mapped = dma->count;
- dma->count = 0;
+ if (dma->dir == DMA_TO_DEVICE) {
+ mapped = sg_dma_len(&dma->tx_sg);
+ } else {
+ mapped = dma->rx.count;
+ dma->rx.count = 0;
+ }
dmaengine_terminate_all(dma->chan);
@@ -265,8 +274,13 @@ static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
val &= ~dma->enable_bit;
msm_write(port, val, UARTDM_DMEN);
- if (mapped)
- dma_unmap_single(dev, dma->phys, mapped, dma->dir);
+ if (mapped) {
+ if (dma->dir == DMA_TO_DEVICE) {
+ dma_unmap_sg(dev, &dma->tx_sg, 1, dma->dir);
+ sg_init_table(&dma->tx_sg, 1);
+ } else
+ dma_unmap_single(dev, dma->rx.phys, mapped, dma->dir);
+ }
}
static void msm_release_dma(struct msm_port *msm_port)
@@ -285,7 +299,7 @@ static void msm_release_dma(struct msm_port *msm_port)
if (dma->chan) {
msm_stop_dma(&msm_port->uart, dma);
dma_release_channel(dma->chan);
- kfree(dma->virt);
+ kfree(dma->rx.virt);
}
memset(dma, 0, sizeof(*dma));
@@ -357,8 +371,8 @@ static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci);
- dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
- if (!dma->virt)
+ dma->rx.virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
+ if (!dma->rx.virt)
goto rel_rx;
memset(&conf, 0, sizeof(conf));
@@ -385,7 +399,7 @@ static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
return;
err:
- kfree(dma->virt);
+ kfree(dma->rx.virt);
rel_rx:
dma_release_channel(dma->chan);
no_rx:
@@ -420,7 +434,7 @@ static void msm_start_tx(struct uart_port *port)
struct msm_dma *dma = &msm_port->tx_dma;
/* Already started in DMA mode */
- if (dma->count)
+ if (sg_dma_len(&dma->tx_sg))
return;
msm_port->imr |= MSM_UART_IMR_TXLEV;
@@ -448,12 +462,12 @@ static void msm_complete_tx_dma(void *args)
uart_port_lock_irqsave(port, &flags);
/* Already stopped */
- if (!dma->count)
+ if (!sg_dma_len(&dma->tx_sg))
goto done;
dmaengine_tx_status(dma->chan, dma->cookie, &state);
- dma_unmap_single(port->dev, dma->phys, dma->count, dma->dir);
+ dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir);
val = msm_read(port, UARTDM_DMEN);
val &= ~dma->enable_bit;
@@ -464,9 +478,9 @@ static void msm_complete_tx_dma(void *args)
msm_write(port, MSM_UART_CR_TX_ENABLE, MSM_UART_CR);
}
- count = dma->count - state.residue;
+ count = sg_dma_len(&dma->tx_sg) - state.residue;
uart_xmit_advance(port, count);
- dma->count = 0;
+ sg_init_table(&dma->tx_sg, 1);
/* Restore "Tx FIFO below watermark" interrupt */
msm_port->imr |= MSM_UART_IMR_TXLEV;
@@ -485,19 +499,18 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
struct circ_buf *xmit = &msm_port->uart.state->xmit;
struct uart_port *port = &msm_port->uart;
struct msm_dma *dma = &msm_port->tx_dma;
- void *cpu_addr;
int ret;
u32 val;
- cpu_addr = &xmit->buf[xmit->tail];
+ sg_init_table(&dma->tx_sg, 1);
+ sg_set_buf(&dma->tx_sg, &xmit->buf[xmit->tail], count);
- dma->phys = dma_map_single(port->dev, cpu_addr, count, dma->dir);
- ret = dma_mapping_error(port->dev, dma->phys);
+ ret = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir);
if (ret)
return ret;
- dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
- count, DMA_MEM_TO_DEV,
+ dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->tx_sg, 1,
+ DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT |
DMA_PREP_FENCE);
if (!dma->desc) {
@@ -520,8 +533,6 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
msm_port->imr &= ~MSM_UART_IMR_TXLEV;
msm_write(port, msm_port->imr, MSM_UART_IMR);
- dma->count = count;
-
val = msm_read(port, UARTDM_DMEN);
val |= dma->enable_bit;
@@ -536,7 +547,8 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
dma_async_issue_pending(dma->chan);
return 0;
unmap:
- dma_unmap_single(port->dev, dma->phys, count, dma->dir);
+ dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir);
+ sg_init_table(&dma->tx_sg, 1);
return ret;
}
@@ -553,7 +565,7 @@ static void msm_complete_rx_dma(void *args)
uart_port_lock_irqsave(port, &flags);
/* Already stopped */
- if (!dma->count)
+ if (!dma->rx.count)
goto done;
val = msm_read(port, UARTDM_DMEN);
@@ -570,14 +582,14 @@ static void msm_complete_rx_dma(void *args)
port->icount.rx += count;
- dma->count = 0;
+ dma->rx.count = 0;
- dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
+ dma_unmap_single(port->dev, dma->rx.phys, UARTDM_RX_SIZE, dma->dir);
for (i = 0; i < count; i++) {
char flag = TTY_NORMAL;
- if (msm_port->break_detected && dma->virt[i] == 0) {
+ if (msm_port->break_detected && dma->rx.virt[i] == 0) {
port->icount.brk++;
flag = TTY_BREAK;
msm_port->break_detected = false;
@@ -588,9 +600,9 @@ static void msm_complete_rx_dma(void *args)
if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK))
flag = TTY_NORMAL;
- sysrq = uart_prepare_sysrq_char(port, dma->virt[i]);
+ sysrq = uart_prepare_sysrq_char(port, dma->rx.virt[i]);
if (!sysrq)
- tty_insert_flip_char(tport, dma->virt[i], flag);
+ tty_insert_flip_char(tport, dma->rx.virt[i], flag);
}
msm_start_rx_dma(msm_port);
@@ -614,13 +626,13 @@ static void msm_start_rx_dma(struct msm_port *msm_port)
if (!dma->chan)
return;
- dma->phys = dma_map_single(uart->dev, dma->virt,
+ dma->rx.phys = dma_map_single(uart->dev, dma->rx.virt,
UARTDM_RX_SIZE, dma->dir);
- ret = dma_mapping_error(uart->dev, dma->phys);
+ ret = dma_mapping_error(uart->dev, dma->rx.phys);
if (ret)
goto sw_mode;
- dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
+ dma->desc = dmaengine_prep_slave_single(dma->chan, dma->rx.phys,
UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT);
if (!dma->desc)
@@ -648,7 +660,7 @@ static void msm_start_rx_dma(struct msm_port *msm_port)
msm_write(uart, msm_port->imr, MSM_UART_IMR);
- dma->count = UARTDM_RX_SIZE;
+ dma->rx.count = UARTDM_RX_SIZE;
dma_async_issue_pending(dma->chan);
@@ -668,7 +680,7 @@ static void msm_start_rx_dma(struct msm_port *msm_port)
return;
unmap:
- dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
+ dma_unmap_single(uart->dev, dma->rx.phys, UARTDM_RX_SIZE, dma->dir);
sw_mode:
/*
@@ -955,7 +967,7 @@ static irqreturn_t msm_uart_irq(int irq, void *dev_id)
}
if (misr & (MSM_UART_IMR_RXLEV | MSM_UART_IMR_RXSTALE)) {
- if (dma->count) {
+ if (dma->rx.count) {
val = MSM_UART_CR_CMD_STALE_EVENT_DISABLE;
msm_write(port, val, MSM_UART_CR);
val = MSM_UART_CR_CMD_RESET_STALE_INT;
--
2.44.0
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