Messages in this thread | | | Date | Thu, 8 Sep 2022 11:27:03 -0700 (PDT) | From | matthew.gerlach@linux ... | Subject | Re: [PATCH v1 5/5] tty: serial: 8250: add DFL bus driver for Altera 16550. |
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On Tue, 6 Sep 2022, Andy Shevchenko wrote:
> On Tue, Sep 06, 2022 at 12:04:26PM -0700, matthew.gerlach@linux.intel.com wrote: >> From: Matthew Gerlach <matthew.gerlach@linux.intel.com> >> >> Add a Device Feature List (DFL) bus driver for the Altera >> 16550 implementation of UART. > > ... > >> +#include <linux/dfl.h> > >> +#include <linux/version.h> > > Hmm... Do we need this?
We do not need this.
> >> +#include <linux/serial.h> >> +#include <linux/serial_8250.h> >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/bitfield.h> >> +#include <linux/io-64-nonatomic-lo-hi.h> > > Can this block be sorted alphabetically?
Yes, they can and should be sorted alphabetically.
> > ... > >> +int feature_uart_walk(struct dfl_uart *dfluart, resource_size_t max) >> +{ >> + void __iomem *param_base; >> + int off; >> + u64 v; >> + >> + v = readq(dfluart->csr_base + DFHv1_CSR_ADDR); >> + dfluart->csr_addr = FIELD_GET(DFHv1_CSR_ADDR_MASK, v); >> + >> + v = readq(dfluart->csr_base + DFHv1_CSR_SIZE_GRP); >> + dfluart->csr_size = FIELD_GET(DFHv1_CSR_SIZE_GRP_SIZE, v); >> + >> + if (dfluart->csr_addr == 0 || dfluart->csr_size == 0) { >> + dev_err(dfluart->dev, "FIXME bad dfh address and size\n"); > > DFH ?
Yes,"DFH" is better than "dfh" in the message.
> >> + return -EINVAL; >> + } >> + >> + if (!FIELD_GET(DFHv1_CSR_SIZE_GRP_HAS_PARAMS, v)) { >> + dev_err(dfluart->dev, "missing required parameters\n"); > > Not sure I understood what parameters are here. FPGA VHDL? Configuration? RTL?
How about "missing required DFH parameters\n"?
> >> + return -EINVAL; >> + } >> + >> + param_base = dfluart->csr_base + DFHv1_PARAM_HDR; >> + >> + off = dfl_find_param(param_base, max, DFHv1_PARAM_ID_CLK_FRQ); >> + if (off < 0) { >> + dev_err(dfluart->dev, "missing CLK_FRQ param\n"); >> + return -EINVAL; >> + } >> + >> + dfluart->uart_clk = readq(param_base + off + DFHv1_PARAM_DATA); > >> + dev_dbg(dfluart->dev, "UART_CLK_ID %llu Hz\n", dfluart->uart_clk); > > Isn't this available via normal interfaces to user?
I am not sure what "normal interfaces to user" you are referring to. The code is just trying to read the frequency of the input clock to the uart from a DFH paramter.
> >> + off = dfl_find_param(param_base, max, DFHv1_PARAM_ID_FIFO_LEN); >> + if (off < 0) { >> + dev_err(dfluart->dev, "missing FIFO_LEN param\n"); >> + return -EINVAL; >> + } >> + >> + dfluart->fifo_len = readq(param_base + off + DFHv1_PARAM_DATA); >> + dev_dbg(dfluart->dev, "UART_FIFO_ID fifo_len %llu\n", dfluart->fifo_len); >> + >> + off = dfl_find_param(param_base, max, DFHv1_PARAM_ID_REG_LAYOUT); >> + if (off < 0) { >> + dev_err(dfluart->dev, "missing REG_LAYOUT param\n"); >> + return -EINVAL; >> + } >> + >> + v = readq(param_base + off + DFHv1_PARAM_DATA); >> + dfluart->fifo_size = FIELD_GET(DFHv1_PARAM_ID_REG_WIDTH, v); >> + dfluart->reg_shift = FIELD_GET(DFHv1_PARAM_ID_REG_SHIFT, v); >> + dev_dbg(dfluart->dev, "UART_LAYOUT_ID width %d shift %d\n", >> + dfluart->fifo_size, dfluart->reg_shift); >> + >> + 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; >> + int ret; >> + >> + memset(&uart, 0, sizeof(uart)); >> + >> + dfluart = devm_kzalloc(dev, sizeof(*dfluart), GFP_KERNEL); >> + if (!dfluart) >> + return -ENOMEM; >> + >> + dfluart->csr_base = devm_ioremap_resource(dev, &dfl_dev->mmio_res); >> + if (IS_ERR(dfluart->csr_base)) { > >> + dev_err(dev, "failed to get mem resource!\n"); > > The above call have a few different messages depending on error code. > No need to repeat this.
I will remove the call to dev_err(). > >> + return PTR_ERR(dfluart->csr_base); >> + } >> + >> + dfluart->dev = dev; >> + >> + ret = feature_uart_walk(dfluart, resource_size(&dfl_dev->mmio_res)); >> + if (ret < 0) { >> + dev_err(dev, "failed to uart feature walk %d\n", ret); > >> + return -EINVAL; > > Why shadowing error code? > What about > > return dev_err_probe(dev, ret, ...); > ? >
Using dev_err_probe seems like the way to go.
>> + } >> + >> + 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]; >> + >> + switch (dfluart->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", dfluart->fifo_len); >> + return -EINVAL; >> + } >> + >> + uart.port.iotype = UPIO_MEM32; >> + uart.port.membase = dfluart->csr_base + dfluart->csr_addr; >> + uart.port.mapsize = dfluart->csr_size; >> + uart.port.regshift = dfluart->reg_shift; >> + uart.port.uartclk = dfluart->uart_clk; >> + >> + /* register the port */ >> + ret = serial8250_register_8250_port(&uart); >> + if (ret < 0) { >> + dev_err(dev, "unable to register 8250 port %d.\n", ret); >> + return -EINVAL; >> + } >> + dev_info(dev, "serial8250_register_8250_port %d\n", ret); >> + dfluart->line = ret; >> + dev_set_drvdata(dev, dfluart); >> + >> + return 0; >> +} >> + >> +static void dfl_uart_remove(struct dfl_device *dfl_dev) >> +{ >> + struct dfl_uart *dfluart = dev_get_drvdata(&dfl_dev->dev); >> + >> + if (dfluart->line > 0) >> + serial8250_unregister_port(dfluart->line); >> +} > > ... > >> +#define FME_FEATURE_ID_UART 0x24 > > Purpose of this definition? For me with or without is still an ID.
I don't think I understand the question. Is the name of the macro unclear, or do you think it is not necessary?
> >> +static const struct dfl_device_id dfl_uart_ids[] = { >> + { FME_ID, FME_FEATURE_ID_UART }, >> + { } >> +}; > > ... > >> +static struct dfl_driver dfl_uart_driver = { >> + .drv = { >> + .name = "dfl-uart", >> + }, >> + .id_table = dfl_uart_ids, >> + .probe = dfl_uart_probe, >> + .remove = dfl_uart_remove, >> +}; > >> + > > No need to have this blank line.
I will remove the blank line.
> >> +module_dfl_driver(dfl_uart_driver); > > ... > >> +MODULE_DEVICE_TABLE(dfl, dfl_uart_ids); > > Move this closer to the definition. That's how other drivers do in the kernel.
Thanks for the suggestion.
> > ... > >> --- a/drivers/tty/serial/8250/Kconfig >> +++ b/drivers/tty/serial/8250/Kconfig > >> --- a/drivers/tty/serial/8250/Makefile >> +++ b/drivers/tty/serial/8250/Makefile > > I know that the records in those files are not sorted, but can you try hard > to find the best place for them in those files from sorting point of view? >
I will try to find a better place from sorting porint of view.
> -- > With Best Regards, > Andy Shevchenko > > >
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