[v4] USB: serial: ftdi_sio: Add MTP NVM support

Message ID 1529920031-26614-1-git-send-email-loic.poulain@linaro.org
State Superseded
Headers show
Series
  • [v4] USB: serial: ftdi_sio: Add MTP NVM support
Related show

Commit Message

Loic Poulain June 25, 2018, 9:47 a.m.
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. For example, FT232R and FTX chips have 128-byte and 2048-byte
internal EEPROM respectively.

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@linaro.org>

---
 v2: Use ifdef instead of IS_ENABLED
     error message in case of nvmem registering failure
     Fix space/tab in Kconfig
 v3: Make nvmem a child of the usb dev instead of the serial port
     Add macros defining eeprom sizes
     Check read/write size is a nultiple of the eeprom word-size
     Remove useless change in Kconfig
 v4: Reword commit message
     Remove default-yes from Kconfig
     Change includes ordering
     Use default linux size defines
     Use get_unaligned_le16 helper
     Prepend EEPROM functions with ftdi_
     Error message in ftdi_eeprom_register()

 drivers/usb/serial/Kconfig    |  10 ++++
 drivers/usb/serial/ftdi_sio.c | 118 ++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/serial/ftdi_sio.h |  28 ++++++++++
 3 files changed, 156 insertions(+)

-- 
2.7.4

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Comments

kbuild test robot June 25, 2018, 12:07 p.m. | #1
Hi Loic,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on usb/usb-testing]
[also build test ERROR on v4.18-rc2 next-20180625]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Loic-Poulain/USB-serial-ftdi_sio-Add-MTP-NVM-support/20180625-181125
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
config: ia64-allyesconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 8.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=8.1.0 make.cross ARCH=ia64 

All errors (new ones prefixed by >>):

   drivers/usb/serial/ftdi_sio.c: In function 'ftdi_register_eeprom':
   drivers/usb/serial/ftdi_sio.c:1603:18: error: 'SZ_2K' undeclared (first use in this function)
      nvmconf.size = SZ_2K;
                     ^~~~~
   drivers/usb/serial/ftdi_sio.c:1603:18: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/usb/serial/ftdi_sio.c:1606:18: error: 'SZ_128' undeclared (first use in this function)

      nvmconf.size = SZ_128;
                     ^~~~~~

vim +/SZ_128 +1606 drivers/usb/serial/ftdi_sio.c

  1594	
  1595	static int ftdi_register_eeprom(struct usb_serial_port *port)
  1596	{
  1597		struct ftdi_private *priv = usb_get_serial_port_data(port);
  1598		struct usb_device *udev = port->serial->dev;
  1599		struct nvmem_config nvmconf = {};
  1600	
  1601		switch (priv->chip_type) {
  1602		case FTX:
> 1603			nvmconf.size = SZ_2K;

  1604			break;
  1605		case FT232RL:
> 1606			nvmconf.size = SZ_128;

  1607			break;
  1608		default:
  1609			return 0;
  1610		}
  1611	
  1612		nvmconf.word_size = 2;
  1613		nvmconf.stride = 2;
  1614		nvmconf.read_only = false;
  1615		nvmconf.priv = port;
  1616		nvmconf.dev = &udev->dev;
  1617		nvmconf.reg_read = ftdi_read_eeprom;
  1618		nvmconf.reg_write = ftdi_write_eeprom;
  1619		nvmconf.owner = THIS_MODULE;
  1620	
  1621		priv->eeprom = nvmem_register(&nvmconf);
  1622		if (IS_ERR(priv->eeprom)) {
  1623			dev_err(&udev->dev, "Unable to register FTDI EEPROM\n");
  1624			priv->eeprom = NULL;
  1625			return -ENOMEM;
  1626		}
  1627	
  1628		dev_info(&udev->dev, "Registered %d-byte FTDI EEPROM\n", nvmconf.size);
  1629	
  1630		return 0;
  1631	}
  1632	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kbuild test robot June 25, 2018, 12:07 p.m. | #2
Hi Loic,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on usb/usb-testing]
[also build test ERROR on v4.18-rc2 next-20180625]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Loic-Poulain/USB-serial-ftdi_sio-Add-MTP-NVM-support/20180625-181125
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
config: x86_64-randconfig-x011-201825 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   drivers/usb/serial/ftdi_sio.c: In function 'ftdi_register_eeprom':
>> drivers/usb/serial/ftdi_sio.c:1603:18: error: 'SZ_2K' undeclared (first use in this function)

      nvmconf.size = SZ_2K;
                     ^~~~~
   drivers/usb/serial/ftdi_sio.c:1603:18: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/usb/serial/ftdi_sio.c:1606:18: error: 'SZ_128' undeclared (first use in this function); did you mean 'SZ_2K'?

      nvmconf.size = SZ_128;
                     ^~~~~~
                     SZ_2K

vim +/SZ_2K +1603 drivers/usb/serial/ftdi_sio.c

  1594	
  1595	static int ftdi_register_eeprom(struct usb_serial_port *port)
  1596	{
  1597		struct ftdi_private *priv = usb_get_serial_port_data(port);
  1598		struct usb_device *udev = port->serial->dev;
  1599		struct nvmem_config nvmconf = {};
  1600	
  1601		switch (priv->chip_type) {
  1602		case FTX:
> 1603			nvmconf.size = SZ_2K;

  1604			break;
  1605		case FT232RL:
> 1606			nvmconf.size = SZ_128;

  1607			break;
  1608		default:
  1609			return 0;
  1610		}
  1611	
  1612		nvmconf.word_size = 2;
  1613		nvmconf.stride = 2;
  1614		nvmconf.read_only = false;
  1615		nvmconf.priv = port;
  1616		nvmconf.dev = &udev->dev;
  1617		nvmconf.reg_read = ftdi_read_eeprom;
  1618		nvmconf.reg_write = ftdi_write_eeprom;
  1619		nvmconf.owner = THIS_MODULE;
  1620	
  1621		priv->eeprom = nvmem_register(&nvmconf);
  1622		if (IS_ERR(priv->eeprom)) {
  1623			dev_err(&udev->dev, "Unable to register FTDI EEPROM\n");
  1624			priv->eeprom = NULL;
  1625			return -ENOMEM;
  1626		}
  1627	
  1628		dev_info(&udev->dev, "Registered %d-byte FTDI EEPROM\n", nvmconf.size);
  1629	
  1630		return 0;
  1631	}
  1632	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Patch

diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 533f127..5747562 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -181,6 +181,16 @@  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
+	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..3f2f2c7 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -37,9 +37,12 @@ 
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 #include <linux/uaccess.h>
+#include <linux/nvmem-provider.h>
 #include <linux/usb.h>
 #include <linux/serial.h>
 #include <linux/usb/serial.h>
+#include <asm/unaligned.h>
+
 #include "ftdi_sio.h"
 #include "ftdi_sio_ids.h"
 
@@ -73,6 +76,8 @@  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 +1534,112 @@  static int get_lsr_info(struct usb_serial_port *port,
 	return 0;
 }
 
+#ifdef CONFIG_USB_SERIAL_FTDI_SIO_NVMEM
+
+static int ftdi_write_eeprom(void *priv, unsigned int off, void *val,
+			     size_t bytes)
+{
+	struct usb_serial_port *port = priv;
+	struct usb_device *udev = port->serial->dev;
+	unsigned char *buf = val;
+
+	if (bytes % 2) /* 16-bit eeprom */
+		return -EINVAL;
+
+	while (bytes) {
+		int rv;
+
+		rv = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				     FTDI_SIO_WRITE_EEPROM_REQUEST,
+				     FTDI_SIO_WRITE_EEPROM_REQUEST_TYPE,
+				     get_unaligned_le16(buf), off / 2, NULL,
+				     0, WDR_TIMEOUT);
+		if (rv < 0)
+			return rv;
+
+		off += 2;
+		buf += 2;
+		bytes -= 2;
+	}
+
+	return 0;
+}
+
+static int ftdi_read_eeprom(void *priv, unsigned int off, void *val,
+			    size_t bytes)
+{
+	struct usb_serial_port *port = priv;
+	struct usb_device *udev = port->serial->dev;
+	unsigned char *buf = val;
+
+	if (bytes % 2) /* 16-bit eeprom */
+		return -EINVAL;
+
+	while (bytes) {
+		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 ftdi_register_eeprom(struct usb_serial_port *port)
+{
+	struct ftdi_private *priv = usb_get_serial_port_data(port);
+	struct usb_device *udev = port->serial->dev;
+	struct nvmem_config nvmconf = {};
+
+	switch (priv->chip_type) {
+	case FTX:
+		nvmconf.size = SZ_2K;
+		break;
+	case FT232RL:
+		nvmconf.size = SZ_128;
+		break;
+	default:
+		return 0;
+	}
+
+	nvmconf.word_size = 2;
+	nvmconf.stride = 2;
+	nvmconf.read_only = false;
+	nvmconf.priv = port;
+	nvmconf.dev = &udev->dev;
+	nvmconf.reg_read = ftdi_read_eeprom;
+	nvmconf.reg_write = ftdi_write_eeprom;
+	nvmconf.owner = THIS_MODULE;
+
+	priv->eeprom = nvmem_register(&nvmconf);
+	if (IS_ERR(priv->eeprom)) {
+		dev_err(&udev->dev, "Unable to register FTDI EEPROM\n");
+		priv->eeprom = NULL;
+		return -ENOMEM;
+	}
+
+	dev_info(&udev->dev, "Registered %d-byte FTDI EEPROM\n", nvmconf.size);
+
+	return 0;
+}
+
+static void ftdi_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 +1925,10 @@  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
+	ftdi_register_eeprom(port);
+#endif
+
 	return 0;
 }
 
@@ -1931,6 +2046,9 @@  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
+	ftdi_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 */