Thanks Bartosz for the patch,
On 23/11/2022 11:07, Bartosz Golaszewski wrote:
From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
The qcom-geni-serial driver currently only works in SE FIFO mode. This
limits the UART speed to around 180 kB/s. In order to achieve higher
speeds we need to use SE DMA mode.
Keep the console port working in FIFO mode but extend the code to use DMA
for the high-speed port.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
drivers/tty/serial/qcom_geni_serial.c | 289 ++++++++++++++++++++++----
1 file changed, 247 insertions(+), 42 deletions(-)
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 82242a40a95a..0f4ba909c792 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -70,6 +70,8 @@
#define UART_START_TX 0x1
/* UART S_CMD OP codes */
#define UART_START_READ 0x1
+#define UART_PARAM 0x1
+#define UART_PARAM_RFR_OPEN BIT(7)
#define UART_OVERSAMPLING 32
#define STALE_TIMEOUT 16
@@ -95,9 +97,11 @@
/* We always configure 4 bytes per FIFO word */
#define BYTES_PER_FIFO_WORD 4
+#define DMA_RX_BUF_SIZE 2048
+
struct qcom_geni_device_data {
bool console;
- void (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
+ enum geni_se_xfer_mode mode;
};
struct qcom_geni_private_data {
@@ -118,9 +122,11 @@ struct qcom_geni_serial_port {
u32 tx_fifo_depth;
u32 tx_fifo_width;
u32 rx_fifo_depth;
+ dma_addr_t tx_dma_addr;
+ dma_addr_t rx_dma_addr;
bool setup;
unsigned int baud;
- void *rx_fifo;
+ void *rx_buf;
u32 loopback;
bool brk;
@@ -552,18 +558,11 @@ static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
static void handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
{
- struct tty_port *tport;
struct qcom_geni_serial_port *port = to_dev_port(uport);
- u32 num_bytes_pw = port->tx_fifo_width / BITS_PER_BYTE;
- u32 words = ALIGN(bytes, num_bytes_pw) / num_bytes_pw;
+ struct tty_port *tport = &uport->state->port;
int ret;
- tport = &uport->state->port;
- ioread32_rep(uport->membase + SE_GENI_RX_FIFOn, port->rx_fifo, words);
- if (drop)
- return;
-
Are we removing FIFO support for uart?
It it not a overhead to use dma for small transfers that are less than
fifo size?
- ret = tty_insert_flip_string(tport, port->rx_fifo, bytes);
+ ret = tty_insert_flip_string(tport, port->rx_buf, bytes);
if (ret != bytes) {
dev_err(uport->dev, "%s:Unable to push data ret %d_bytes %d\n",
__func__, ret, bytes);
@@ -578,7 +577,70 @@ static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
return !readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
}
-static void qcom_geni_serial_start_tx(struct uart_port *uport)
+static void qcom_geni_serial_stop_tx_dma(struct uart_port *uport)
+{
+ struct qcom_geni_serial_port *port = to_dev_port(uport);
+ bool done;
-->
+ u32 status;
...
+
+ status = readl(uport->membase + SE_GENI_STATUS);
+ if (!(status & M_GENI_CMD_ACTIVE))
+ return;
<---
this code snippet is repeating more than few times in the patches, looks
like it could be made to a inline helper.
+
+ if (port->rx_dma_addr) {
+ geni_se_tx_dma_unprep(&port->se, port->tx_dma_addr,
+ port->tx_remaining);
+ port->tx_dma_addr = (dma_addr_t)NULL;
+ port->tx_remaining = 0;
+ }
+
+ m_irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
+ writel(m_irq_en, uport->membase + SE_GENI_M_IRQ_EN);
+ geni_se_cancel_m_cmd(&port->se);
+
+ done = qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS,
+ S_CMD_CANCEL_EN, true);
+ if (!done) {
+ geni_se_abort_m_cmd(&port->se);
+ qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
+ M_CMD_ABORT_EN, true);
return is not checked, there are few more such instances in the patch.
+ writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
+ }
+
+ writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
+}
+
+static void qcom_geni_serial_start_tx_dma(struct uart_port *uport)
+{
+ struct qcom_geni_serial_port *port = to_dev_port(uport);
+ struct circ_buf *xmit = &uport->state->xmit;
+ unsigned int xmit_size;
+ int ret;
+
+ if (port->tx_dma_addr)
+ return;
Is this condition actually possible?
+
+ xmit_size = uart_circ_chars_pending(xmit);
+ if (xmit_size < WAKEUP_CHARS)
+ uart_write_wakeup(uport);
+
+ xmit_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+
+ qcom_geni_serial_setup_tx(uport, xmit_size);
+
+ ret = geni_se_tx_dma_prep(&port->se, &xmit->buf[xmit->tail],
+ xmit_size, &port->tx_dma_addr);
+ if (ret) {
+ dev_err(uport->dev, "unable to start TX SE DMA: %d\n", ret);
+ qcom_geni_serial_stop_tx_dma(uport);
+ return;
+ }
+
+ port->tx_remaining = xmit_size;
+}
+
...
