| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <alpine.DEB.2.22.394.2210061445220.1772307@rhweight-WRK1>
Date: Thu, 6 Oct 2022 14:47:40 -0700 (PDT)
From: matthew.gerlach@...ux.intel.com
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
cc: hao.wu@...el.com, yilun.xu@...el.com, russell.h.weight@...el.com,
basheer.ahmed.muddebihal@...el.com, trix@...hat.com,
mdf@...nel.org, linux-fpga@...r.kernel.org,
linux-doc@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
tianfei.zhang@...el.com, corbet@....net,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-serial <linux-serial@...r.kernel.org>,
Jiri Slaby <jirislaby@...nel.org>, geert+renesas@...der.be,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
niklas.soderlund+renesas@...natech.se, macro@...am.me.uk,
johan@...nel.org, Lukas Wunner <lukas@...ner.de>,
kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v3 4/4] tty: serial: 8250: add DFL bus driver for Altera
16550.
On Wed, 5 Oct 2022, Ilpo Järvinen wrote:
> On Tue, 4 Oct 2022, matthew.gerlach@...ux.intel.com wrote:
>
>> From: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>>
>> Add a Device Feature List (DFL) bus driver for the Altera
>> 16550 implementation of UART.
>>
>> Signed-off-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
>> Reported-by: kernel test robot <lkp@...el.com>
>> ---
>> 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.
>
>
Powered by blists - more mailing lists