patch "serial: 8250_exar: Fix number of ports for Commtech PCIe cards" added to tty-linus

This is a note to let you know that I've just added the patch titled

serial: 8250_exar: Fix number of ports for Commtech PCIe cards

to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From c6b9e95dde7b54e6a53c47241201ab5a4035c320 Mon Sep 17 00:00:00 2001
From: Valmer Huhn <[email protected]>
Date: Thu, 13 Aug 2020 12:52:55 -0400
Subject: serial: 8250_exar: Fix number of ports for Commtech PCIe cards

The following in 8250_exar.c line 589 is used to determine the number of ports for each Exar board:

nr_ports = board->num_ports ? board->num_ports : pcidev->device & 0x0f;

If the number of ports a card has is not explicitly specified, it defaults to the rightmost 4 bits of the PCI device ID. This is prone to error since not all PCI device IDs contain a number which corresponds to the number of ports that card provides.

This particular case involves COMMTECH_4222PCIE, COMMTECH_4224PCIE and COMMTECH_4228PCIE cards with device IDs 0x0022, 0x0020 and 0x0021. Currently the multiport cards receive 2, 0 and 1 port instead of 2, 4 and 8 ports respectively.

To fix this, each Commtech Fastcom PCIe card is given a struct where the number of ports is explicitly specified. This ensures 'board->num_ports' is used instead of the default 'pcidev->device & 0x0f'.

---
 drivers/tty/serial/8250/8250_exar.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

index 04b9af7ed941..2d0e7c7e408d 100644
@@ -744,6 +744,24 @@ static const struct exar8250_board pbn_exar_XR17V35x = {
 	.exit		= pci_xr17v35x_exit,
 };
 
+static const struct exar8250_board pbn_fastcom35x_2 = {
+	.num_ports	= 2,
+	.setup		= pci_xr17v35x_setup,
+	.exit		= pci_xr17v35x_exit,
+};
+
+static const struct exar8250_board pbn_fastcom35x_4 = {
+	.num_ports	= 4,
+	.setup		= pci_xr17v35x_setup,
+	.exit		= pci_xr17v35x_exit,
+};
+
+static const struct exar8250_board pbn_fastcom35x_8 = {
+	.num_ports	= 8,
+	.setup		= pci_xr17v35x_setup,
+	.exit		= pci_xr17v35x_exit,
+};
+
 static const struct exar8250_board pbn_exar_XR17V4358 = {
 	.num_ports	= 12,
 	.setup		= pci_xr17v35x_setup,

@@ -811,9 +829,9 @@ static const struct pci_device_id exar_pci_tbl[] = {
 	EXAR_DEVICE(EXAR, XR17V358, pbn_exar_XR17V35x),
 	EXAR_DEVICE(EXAR, XR17V4358, pbn_exar_XR17V4358),
 	EXAR_DEVICE(EXAR, XR17V8358, pbn_exar_XR17V8358),
-	EXAR_DEVICE(COMMTECH, 4222PCIE, pbn_exar_XR17V35x),
-	EXAR_DEVICE(COMMTECH, 4224PCIE, pbn_exar_XR17V35x),
-	EXAR_DEVICE(COMMTECH, 4228PCIE, pbn_exar_XR17V35x),
+	EXAR_DEVICE(COMMTECH, 4222PCIE, pbn_fastcom35x_2),
+	EXAR_DEVICE(COMMTECH, 4224PCIE, pbn_fastcom35x_4),
+	EXAR_DEVICE(COMMTECH, 4228PCIE, pbn_fastcom35x_8),
 
 	EXAR_DEVICE(COMMTECH, 4222PCI335, pbn_fastcom335_2),
 	EXAR_DEVICE(COMMTECH, 4224PCI335, pbn_fastcom335_4),

2.28.0