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Commit 8b5c913f authored by Wang YanQing's avatar Wang YanQing Committed by Greg Kroah-Hartman
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serial: 8250_pci: Add WCH CH352 quirk to avoid Xscale detection 



The code in 8250.c for detecting ARM/XScale UARTs says:

  * Try writing and reading the UART_IER_UUE bit (b6).
  * If it works, this is probably one of the Xscale platform's
  * internal UARTs.

If the above passes, it then goes on to:

     * It's an Xscale.
     * We'll leave the UART_IER_UUE bit set to 1 (enabled).

However, the CH352 uses the UART_IER_UUE as the LOWPOWER function,
so it is readable and writable.  According to the datasheet:

    "LOWPOWER:When the bit is 1, close the internal benchmark
     clock of serial port to set into low-power status.

So it essentially gets mis-detected as Xscale, and gets
powered down in the process.  The device in question where
this was seen is listed by lspci as:

 Serial controller: Device 4348:3253 (rev 10) (prog-if 02 [16550])

Re-using the 353 quirk which just sets flags to fixed and type
to 16550 is suitable for fixing the 352 as well.

Signed-off-by: default avatarWang YanQing <udknight@gmail.com>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 503bded9

drivers/tty/serial/8250/8250_pci.c

+13 −0
Original line number Diff line number Diff line
@@ -1554,6 +1554,7 @@ pci_wch_ch353_setup(struct serial_private *priv, 
#define PCI_DEVICE_ID_PLX_CRONYX_OMEGA	0xc001

#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d

#define PCI_VENDOR_ID_WCH		0x4348

#define PCI_DEVICE_ID_WCH_CH352_2S	0x3253

#define PCI_DEVICE_ID_WCH_CH353_4S	0x3453

#define PCI_DEVICE_ID_WCH_CH353_2S1PF	0x5046

#define PCI_DEVICE_ID_WCH_CH353_2S1P	0x7053
@@ -2172,6 +2173,14 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = { 
		.subdevice      = PCI_ANY_ID,

		.setup          = pci_wch_ch353_setup,

	},

	/* WCH CH352 2S card (16550 clone) */

	{

		.vendor		= PCI_VENDOR_ID_WCH,

		.device		= PCI_DEVICE_ID_WCH_CH352_2S,

		.subvendor	= PCI_ANY_ID,

		.subdevice	= PCI_ANY_ID,

		.setup		= pci_wch_ch353_setup,

	},

	/*

	 * ASIX devices with FIFO bug

	 */
@@ -4870,6 +4879,10 @@ static struct pci_device_id serial_pci_tbl[] = { 
		PCI_ANY_ID, PCI_ANY_ID,

		0, 0, pbn_b0_bt_2_115200 },



	{	PCI_VENDOR_ID_WCH, PCI_DEVICE_ID_WCH_CH352_2S,

		PCI_ANY_ID, PCI_ANY_ID,

		0, 0, pbn_b0_bt_2_115200 },



	/*

	 * Commtech, Inc. Fastcom adapters

	 */