serial: qcom_geni_serial: Always use 4 bytes per TX FIFO word

The geni serial driver had a rule that we'd only use 1 byte per FIFO
word for the TX FIFO if we were being used for the serial console.
This is ugly and a bit of a pain.  It's not too hard to fix, so fix
it.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200626125844.2.Iabd56347670b9e4e916422773aba5b27943d19ee@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 4610e391e8869aacbf48a21fa67d65177d9ee6cc..583d903321b545cd7dfb21cd0cede3706f349c84 100644 (file)
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -103,12 +103,18 @@
 #define DEFAULT_IO_MACRO_IO2_IO3_MASK          GENMASK(15, 4)
 #define IO_MACRO_IO2_IO3_SWAP          0x4640
 
+/* We always configure 4 bytes per FIFO word */
+#define BYTES_PER_FIFO_WORD            4
+
 struct qcom_geni_private_data {
        /* NOTE: earlycon port will have NULL here */
        struct uart_driver *drv;
 
        u32 poll_cached_bytes;
        unsigned int poll_cached_bytes_cnt;
+
+       u32 write_cached_bytes;
+       unsigned int write_cached_bytes_cnt;
 };
 
 struct qcom_geni_serial_port {
@@ -121,8 +127,6 @@ struct qcom_geni_serial_port {
        bool setup;
        int (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
        unsigned int baud;
-       unsigned int tx_bytes_pw;
-       unsigned int rx_bytes_pw;
        void *rx_fifo;
        u32 loopback;
        bool brk;
@@ -390,13 +394,25 @@ static void qcom_geni_serial_poll_put_char(struct uart_port *uport,
 #ifdef CONFIG_SERIAL_QCOM_GENI_CONSOLE
 static void qcom_geni_serial_wr_char(struct uart_port *uport, int ch)
 {
-       writel(ch, uport->membase + SE_GENI_TX_FIFOn);
+       struct qcom_geni_private_data *private_data = uport->private_data;
+
+       private_data->write_cached_bytes =
+               (private_data->write_cached_bytes >> 8) | (ch << 24);
+       private_data->write_cached_bytes_cnt++;
+
+       if (private_data->write_cached_bytes_cnt == BYTES_PER_FIFO_WORD) {
+               writel(private_data->write_cached_bytes,
+                      uport->membase + SE_GENI_TX_FIFOn);
+               private_data->write_cached_bytes_cnt = 0;
+       }
 }
 
 static void
 __qcom_geni_serial_console_write(struct uart_port *uport, const char *s,
                                 unsigned int count)
 {
+       struct qcom_geni_private_data *private_data = uport->private_data;
+
        int i;
        u32 bytes_to_send = count;
 
@@ -431,6 +447,15 @@ __qcom_geni_serial_console_write(struct uart_port *uport, const char *s,
                                                        SE_GENI_M_IRQ_CLEAR);
                i += chars_to_write;
        }
+
+       if (private_data->write_cached_bytes_cnt) {
+               private_data->write_cached_bytes >>= BITS_PER_BYTE *
+                       (BYTES_PER_FIFO_WORD - private_data->write_cached_bytes_cnt);
+               writel(private_data->write_cached_bytes,
+                      uport->membase + SE_GENI_TX_FIFOn);
+               private_data->write_cached_bytes_cnt = 0;
+       }
+
        qcom_geni_serial_poll_tx_done(uport);
 }
 
@@ -503,7 +528,7 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
        tport = &uport->state->port;
        for (i = 0; i < bytes; ) {
                int c;
-               int chunk = min_t(int, bytes - i, port->rx_bytes_pw);
+               int chunk = min_t(int, bytes - i, BYTES_PER_FIFO_WORD);
 
                ioread32_rep(uport->membase + SE_GENI_RX_FIFOn, buf, 1);
                i += chunk;
@@ -683,11 +708,11 @@ static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
 
        if (!word_cnt)
                return;
-       total_bytes = port->rx_bytes_pw * (word_cnt - 1);
+       total_bytes = BYTES_PER_FIFO_WORD * (word_cnt - 1);
        if (last_word_partial && last_word_byte_cnt)
                total_bytes += last_word_byte_cnt;
        else
-               total_bytes += port->rx_bytes_pw;
+               total_bytes += BYTES_PER_FIFO_WORD;
        port->handle_rx(uport, total_bytes, drop);
 }
 
@@ -720,7 +745,7 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
        }
 
        avail = port->tx_fifo_depth - (status & TX_FIFO_WC);
-       avail *= port->tx_bytes_pw;
+       avail *= BYTES_PER_FIFO_WORD;
 
        tail = xmit->tail;
        chunk = min(avail, pending);
@@ -744,7 +769,7 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
                int c;
 
                memset(buf, 0, ARRAY_SIZE(buf));
-               tx_bytes = min_t(size_t, remaining, port->tx_bytes_pw);
+               tx_bytes = min_t(size_t, remaining, BYTES_PER_FIFO_WORD);
 
                for (c = 0; c < tx_bytes ; c++) {
                        buf[c] = xmit->buf[tail++];
@@ -861,12 +886,6 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
        u32 proto;
        u32 pin_swap;
 
-       if (uart_console(uport))
-               port->tx_bytes_pw = 1;
-       else
-               port->tx_bytes_pw = 4;
-       port->rx_bytes_pw = 4;
-
        proto = geni_se_read_proto(&port->se);
        if (proto != GENI_SE_UART) {
                dev_err(uport->dev, "Invalid FW loaded, proto: %d\n", proto);
@@ -898,10 +917,8 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
         */
        if (uart_console(uport))
                qcom_geni_serial_poll_tx_done(uport);
-       geni_se_config_packing(&port->se, BITS_PER_BYTE, port->tx_bytes_pw,
-                                               false, true, false);
-       geni_se_config_packing(&port->se, BITS_PER_BYTE, port->rx_bytes_pw,
-                                               false, false, true);
+       geni_se_config_packing(&port->se, BITS_PER_BYTE, BYTES_PER_FIFO_WORD,
+                              false, true, true);
        geni_se_init(&port->se, UART_RX_WM, port->rx_fifo_depth - 2);
        geni_se_select_mode(&port->se, GENI_SE_FIFO);
        port->setup = true;
@@ -1197,8 +1214,8 @@ static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,
         */
        qcom_geni_serial_poll_tx_done(uport);
        qcom_geni_serial_abort_rx(uport);
-       geni_se_config_packing(&se, BITS_PER_BYTE, 1, false, true, false);
-       geni_se_config_packing(&se, BITS_PER_BYTE, 4, false, false, true);
+       geni_se_config_packing(&se, BITS_PER_BYTE, BYTES_PER_FIFO_WORD,
+                              false, true, true);
        geni_se_init(&se, DEF_FIFO_DEPTH_WORDS / 2, DEF_FIFO_DEPTH_WORDS - 2);
        geni_se_select_mode(&se, GENI_SE_FIFO);