On Wed, 5 Oct 2022, Ilpo Järvinen wrote:
On Tue, 4 Oct 2022, matthew.gerlach@xxxxxxxxxxxxxxx wrote:
From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
Add a Device Feature List (DFL) bus driver for the Altera
16550 implementation of UART.
Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
---
v3: use passed in location of registers
use cleaned up functions for parsing parameters
v2: clean up error messages
alphabetize header files
fix 'missing prototype' error by making function static
tried to sort Makefile and Kconfig better
---
drivers/tty/serial/8250/8250_dfl.c | 177 +++++++++++++++++++++++++++++
drivers/tty/serial/8250/Kconfig | 9 ++
drivers/tty/serial/8250/Makefile | 1 +
3 files changed, 187 insertions(+)
create mode 100644 drivers/tty/serial/8250/8250_dfl.c
diff --git a/drivers/tty/serial/8250/8250_dfl.c b/drivers/tty/serial/8250/8250_dfl.c
new file mode 100644
index 000000000000..110ad3a73459
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_dfl.c
@@ -0,0 +1,177 @@
+static int dfl_uart_get_params(struct device *dev, void __iomem *dfh_base, resource_size_t max,
+ struct uart_8250_port *uart)
+{
+ u64 v, fifo_len, reg_width;
+ int off;
+
+ if (!dfhv1_has_params(dfh_base)) {
+ dev_err(dev, "missing required DFH parameters\n");
+ return -EINVAL;
+ }
+
+ off = dfhv1_find_param(dfh_base, max, DFHv1_PARAM_ID_CLK_FRQ);
+ if (off < 0) {
+ dev_err(dev, "missing CLK_FRQ param\n");
+ return -EINVAL;
+ }
+
+ uart->port.uartclk = readq(dfh_base + off);
+ dev_dbg(dev, "UART_CLK_ID %u Hz\n", uart->port.uartclk);
+
+ off = dfhv1_find_param(dfh_base, max, DFHv1_PARAM_ID_FIFO_LEN);
+ if (off < 0) {
+ dev_err(dev, "missing FIFO_LEN param\n");
+ return -EINVAL;
+ }
+
+ fifo_len = readq(dfh_base + off);
+ dev_dbg(dev, "UART_FIFO_ID fifo_len %llu\n", fifo_len);
+
+ switch (fifo_len) {
+ case 32:
+ uart->port.type = PORT_ALTR_16550_F32;
+ break;
+
+ case 64:
+ uart->port.type = PORT_ALTR_16550_F64;
+ break;
+
+ case 128:
+ uart->port.type = PORT_ALTR_16550_F128;
+ break;
+
+ default:
+ dev_err(dev, "bad fifo_len %llu\n", fifo_len);
I'd tell user "unsupported" rather than "bad".
The word, unsupported, sounds better. I will change it in both places you
suggested.
+ return -EINVAL;
+ }
+
+ off = dfhv1_find_param(dfh_base, max, DFHv1_PARAM_ID_REG_LAYOUT);
+ if (off < 0) {
+ dev_err(dev, "missing REG_LAYOUT param\n");
+ return -EINVAL;
+ }
+
+ v = readq(dfh_base + off);
+ uart->port.regshift = FIELD_GET(DFHv1_PARAM_ID_REG_SHIFT, v);
+ reg_width = FIELD_GET(DFHv1_PARAM_ID_REG_WIDTH, v);
+
+ dev_dbg(dev, "UART_LAYOUT_ID width %lld shift %d\n",
+ FIELD_GET(DFHv1_PARAM_ID_REG_WIDTH, v), (int)uart->port.regshift);
Why not use reg_width directly?
Good catch.
+ switch (reg_width) {
+ case 4:
+ uart->port.iotype = UPIO_MEM32;
+ break;
+
+ case 2:
+ uart->port.iotype = UPIO_MEM16;
+ break;
+
+ default:
+ dev_err(dev, "invalid reg_width %lld\n", reg_width);
unsupported ?
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int dfl_uart_probe(struct dfl_device *dfl_dev)
+{
+ struct device *dev = &dfl_dev->dev;
+ struct uart_8250_port uart;
+ struct dfl_uart *dfluart;
+ resource_size_t res_size;
+ void __iomem *dfh_base;
+ int ret;
+
+ memset(&uart, 0, sizeof(uart));
+ uart.port.flags = UPF_IOREMAP;
+ uart.port.mapbase = dfl_dev->csr_res.start;
+ uart.port.mapsize = resource_size(&dfl_dev->csr_res);
+
+ dfluart = devm_kzalloc(dev, sizeof(*dfluart), GFP_KERNEL);
+ if (!dfluart)
+ return -ENOMEM;
+
+ dfh_base = devm_ioremap_resource(dev, &dfl_dev->mmio_res);
+ if (IS_ERR(dfh_base))
+ return PTR_ERR(dfh_base);
+
+ res_size = resource_size(&dfl_dev->mmio_res);
+
+ ret = dfl_uart_get_params(dev, dfh_base, res_size, &uart);
+
+ devm_iounmap(dev, dfh_base);
+ devm_release_mem_region(dev, dfl_dev->mmio_res.start, res_size);
+
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "failed uart feature walk\n");
+
+ dev_dbg(dev, "nr_irqs %d %p\n", dfl_dev->num_irqs, dfl_dev->irqs);
+
+ if (dfl_dev->num_irqs == 1)
+ uart.port.irq = dfl_dev->irqs[0];
+
+ /* register the port */
This comment is pretty useless. Just drop it.
Will drop this useless comment.
+ dfluart->line = serial8250_register_8250_port(&uart);
+ if (dfluart->line < 0)
+ return dev_err_probe(dev, dfluart->line, "unable to register 8250 port.\n");
+
+ dev_info(dev, "serial8250_register_8250_port %d\n", dfluart->line);
This you want to drop too. It seems a debug thing rather than info level
stuff.
It is actually redundant output because serial8250_register_8250_port()
produces useful output. I will drop the line.
--
i.
