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) {
}
> + 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
> + 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.
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
>
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