Hi Ajay,
Thanks for the review.
On 21 June 2018 at 19:34, Ajay Gupta <ajaykuee@xxxxxxxxx> wrote:
> Hi Loic
>
> On 6/21/18, Loic Poulain <loic.poulain@xxxxxxxxxx> wrote:
>> Most of FTDI's devices have an EEPROM which records FTDI devices
>> configuration setting (e.g. the VID, PID, I/O config...) and user
>> data. FT230R chip integrates a 128-byte eeprom, FT230X a 2048-byte
>> eeprom...
>>
>> This patch adds support for FTDI EEPROM read/write via USB control
>> transfers and register a new nvm device to the nvmem core.
>>
>> This permits to expose the eeprom as a sysfs file, allowing userspace
>> to read/modify FTDI configuration and its user data without having to
>> rely on a specific userspace USB driver.
>>
>> Moreover, any upcoming new tentative to add CBUS GPIO support could
>> integrate CBUS EEPROM configuration reading in order to determine
>> which of the CBUS pins are available as GPIO.
>>
>> Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
>> ---
>> v2: Use ifdef instead of IS_ENABLED
>> error message in case of nvmem registering failure
>> Fix space/tab in Kconfig
>>
>> drivers/usb/serial/Kconfig | 13 ++++-
>> drivers/usb/serial/ftdi_sio.c | 111
>> ++++++++++++++++++++++++++++++++++++++++++
>> drivers/usb/serial/ftdi_sio.h | 28 +++++++++++
>> 3 files changed, 151 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
>> index 533f127..f05af5f 100644
>> --- a/drivers/usb/serial/Kconfig
>> +++ b/drivers/usb/serial/Kconfig
>> @@ -153,7 +153,7 @@ config USB_SERIAL_CYPRESS_M8
>>
>> Supported microcontrollers in the CY4601 family are:
>> CY7C63741 CY7C63742 CY7C63743 CY7C64013
>> -
>> +
> There is no change here so please remove it.
>
>> To compile this driver as a module, choose M here: the
>> module will be called cypress_m8.
>>
>> @@ -181,6 +181,17 @@ config USB_SERIAL_FTDI_SIO
>> To compile this driver as a module, choose M here: the
>> module will be called ftdi_sio.
>>
>> +config USB_SERIAL_FTDI_SIO_NVMEM
>> + bool "FTDI MTP non-volatile memory support"
>> + depends on USB_SERIAL_FTDI_SIO
>> + select NVMEM
>> + default y
>> + help
>> + Say yes here to add support for the MTP non-volatile memory
>> + present on FTDI. Most of FTDI's devices have an EEPROM which
>> + records FTDI device's configuration setting as well as user
>> + data.
>> +
>> config USB_SERIAL_VISOR
>> tristate "USB Handspring Visor / Palm m50x / Sony Clie Driver"
>> help
>> diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
>> index 7ea221d..9e242e8 100644
>> --- a/drivers/usb/serial/ftdi_sio.c
>> +++ b/drivers/usb/serial/ftdi_sio.c
>> @@ -40,6 +40,7 @@
>> #include <linux/usb.h>
>> #include <linux/serial.h>
>> #include <linux/usb/serial.h>
>> +#include <linux/nvmem-provider.h>
>> #include "ftdi_sio.h"
>> #include "ftdi_sio_ids.h"
>>
>> @@ -73,6 +74,8 @@ struct ftdi_private {
>> unsigned int latency; /* latency setting in use */
>> unsigned short max_packet_size;
>> struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl()
>> and change_speed() */
>> +
>> + struct nvmem_device *eeprom;
>> };
>>
>> /* struct ftdi_sio_quirk is used by devices requiring special attention.
>> */
>> @@ -1529,6 +1532,104 @@ static int get_lsr_info(struct usb_serial_port
>> *port,
>> return 0;
>> }
>>
>> +#ifdef CONFIG_USB_SERIAL_FTDI_SIO_NVMEM
>> +
>> +static int write_eeprom(void *priv, unsigned int off, void *_val, size_t
>> bytes)
>> +{
>> + struct usb_serial_port *port = priv;
>> + struct usb_serial *serial = port->serial;
>> + struct usb_device *udev = serial->dev;
>> + unsigned char *buf = _val;
>> +
>> + while (bytes) { /* bytes value is always a multiple of 2 */
>
> We should add check that 'bytes' is always multiple of 2 otherwise in
> case its not then there will be memory overrun due to buf[1] access
> below.
> while (bytes / 2) {
> }
>
This is in theory something which is guaranteed by the nvmem core since
we specified a 2-byte word size on registering. But looking at the code,
word-size is only checked on userspace access, not with kernel API
(e.g. nvmem_device_write). So yes It could be worth to double check here.
>> + uint16_t val;
>> + int rv;
>> +
>> + val = buf[0] + (buf[1] << 8);
>> +
>> + rv = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
>> + FTDI_SIO_WRITE_EEPROM_REQUEST,
>> + FTDI_SIO_WRITE_EEPROM_REQUEST_TYPE,
>> + val, off / 2, NULL, 0, WDR_TIMEOUT);
>> + if (rv < 0)
>> + return rv;
>> +
>> + off += 2;
>> + buf += 2;
>> + bytes -= 2;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int read_eeprom(void *priv, unsigned int off, void *val, size_t
>> bytes)
>> +{
>> + struct usb_serial_port *port = priv;
>> + struct usb_serial *serial = port->serial;
>> + struct usb_device *udev = serial->dev;
>> + unsigned char *buf = val;
>> +
>> + while (bytes) { /* bytes value is always a multiple of 2 */
> same here
Ok.
>
>> + int rv;
>> +
>> + rv = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
>> + FTDI_SIO_READ_EEPROM_REQUEST,
>> + FTDI_SIO_READ_EEPROM_REQUEST_TYPE,
>> + 0, off / 2, buf, 2, WDR_TIMEOUT);
>> + if (rv < 0)
>> + return rv;
>> +
>> + off += 2;
>> + buf += 2;
>> + bytes -= 2;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int register_eeprom(struct usb_serial_port *port)
>> +{
>> + struct ftdi_private *priv = usb_get_serial_port_data(port);
>> + struct nvmem_config nvmconf = {};
>> +
>> + switch (priv->chip_type) {
>> + case FTX:
>> + nvmconf.size = 2048;
> Better to have macro for 2048 and 128 instead of hardcoded value.
>
Ok.
> Thanks
> Ajay
>> + break;
>> + case FT232RL:
>> + nvmconf.size = 128;
>> + break;
>> + default:
>> + return 0;
>> + }
>> +
>> + nvmconf.word_size = 2;
>> + nvmconf.stride = 2;
>> + nvmconf.read_only = false;
>> + nvmconf.priv = port;
>> + nvmconf.dev = &port->dev;
>> + nvmconf.reg_read = read_eeprom;
>> + nvmconf.reg_write = write_eeprom;
>> + nvmconf.owner = THIS_MODULE;
>> +
>> + priv->eeprom = nvmem_register(&nvmconf);
>> + if (IS_ERR(priv->eeprom)) {
>> + priv->eeprom = NULL;
>> + return -ENOMEM;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void unregister_eeprom(struct usb_serial_port *port)
>> +{
>> + struct ftdi_private *priv = usb_get_serial_port_data(port);
>> +
>> + if (priv->eeprom)
>> + nvmem_unregister(priv->eeprom);
>> +}
>> +
>> +#endif /* CONFIG_USB_SERIAL_FTDI_SIO_NVMEM */
>>
>> /* Determine type of FTDI chip based on USB config and descriptor. */
>> static void ftdi_determine_type(struct usb_serial_port *port)
>> @@ -1814,6 +1915,13 @@ static int ftdi_sio_port_probe(struct usb_serial_port
>> *port)
>> priv->latency = 16;
>> write_latency_timer(port);
>> create_sysfs_attrs(port);
>> +#ifdef CONFIG_USB_SERIAL_FTDI_SIO_NVMEM
>> + if (register_eeprom(port)) {
>> + dev_err(&port->dev, "Unable to register FTDI EEPROM\n");
>> + /* non-fatal */
>> + }
>> +#endif
>> +
>> return 0;
>> }
>>
>> @@ -1931,6 +2039,9 @@ static int ftdi_sio_port_remove(struct usb_serial_port
>> *port)
>> {
>> struct ftdi_private *priv = usb_get_serial_port_data(port);
>>
>> +#ifdef CONFIG_USB_SERIAL_FTDI_SIO_NVMEM
>> + unregister_eeprom(port);
>> +#endif
>> remove_sysfs_attrs(port);
>>
>> kfree(priv);
>> diff --git a/drivers/usb/serial/ftdi_sio.h b/drivers/usb/serial/ftdi_sio.h
>> index dcd0b6e..9eab961 100644
>> --- a/drivers/usb/serial/ftdi_sio.h
>> +++ b/drivers/usb/serial/ftdi_sio.h
>> @@ -36,6 +36,8 @@
>> #define FTDI_SIO_SET_ERROR_CHAR 7 /* Set the error character */
>> #define FTDI_SIO_SET_LATENCY_TIMER 9 /* Set the latency timer */
>> #define FTDI_SIO_GET_LATENCY_TIMER 10 /* Get the latency timer */
>> +#define FTDI_SIO_READ_EEPROM 0x90 /* Read eeprom */
>> +#define FTDI_SIO_WRITE_EEPROM 0x91 /* Write eeprom */
>>
>> /* Interface indices for FT2232, FT2232H and FT4232H devices */
>> #define INTERFACE_A 1
>> @@ -400,6 +402,32 @@ enum ftdi_sio_baudrate {
>> *
>> */
>>
>> + /* FTDI_SIO_READ_EEPROM */
>> +#define FTDI_SIO_READ_EEPROM_REQUEST_TYPE 0xc0
>> +#define FTDI_SIO_READ_EEPROM_REQUEST FTDI_SIO_READ_EEPROM
>> +/*
>> + * BmRequestType: 1100 0000b
>> + * bRequest: FTDI_SIO_READ_EEPROM
>> + * wValue: 0
>> + * wIndex: Word Index
>> + * wLength: 2
>> + * Data: return data (a word)
>> + *
>> + */
>> +
>> +/* FTDI_SIO_WRITE_EEPROM */
>> +#define FTDI_SIO_WRITE_EEPROM_REQUEST_TYPE 0x40
>> +#define FTDI_SIO_WRITE_EEPROM_REQUEST FTDI_SIO_WRITE_EEPROM
>> +/*
>> + * BmRequestType: 0100 0000b
>> + * bRequest: FTDI_SIO_WRITE_EEPROM
>> + * wValue: Data (word)
>> + * wIndex: Word Index
>> + * wLength: 0
>> + * Data: None
>> + *
>> + */
>> +
>> /* FTDI_SIO_GET_MODEM_STATUS */
>> /* Retrieve the current value of the modem status register */
>>
>> --
>> 2.7.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
Regards,
Loic
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
