FAILED: patch "[PATCH] serial: 8250_mid: Disable DMA for selected platforms" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] serial: 8250_mid: Disable DMA for selected platforms" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x b1b4efea05a56c0995e4702a86d6624b4fdff32f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071458-footpad-hunting-e8d7@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b1b4efea05a56c0995e4702a86d6624b4fdff32f Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Fri, 26 Jun 2026 11:49:37 +0200
Subject: [PATCH] serial: 8250_mid: Disable DMA for selected platforms

In accordance with Errata (specification updates)
HSUART May Stop Functioning when DMA is Active.

- Denverton document #572409, rev 3.4, DNV60
- Ice Lake Xeon D document #714070, ICXD65
- Snowridge document #731931, SNR44

For a quick fix just disable the respective callbacks during the device probe.
Depending on the future development we might remove them completely.

Reported-by: micas-opensource <zjianan156@gmail.com>
Closes: https://lore.kernel.org/linux-serial/20250625031409.2404219-1-opensource@ruijie.com.cn/
Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260626094937.561776-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index 8ec03863606e..f88809ff370b 100644
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/rational.h>
+#include <linux/util_macros.h>
 
 #include <linux/dma/hsu.h>
 
@@ -368,8 +369,16 @@ static const struct mid8250_board dnv_board = {
 	.freq = 133333333,
 	.base_baud = 115200,
 	.bar = 1,
-	.setup = dnv_setup,
-	.exit = dnv_exit,
+	/*
+	 * Errata:
+	 * HSUART May Stop Functioning when DMA is Active.
+	 *
+	 * - Denverton document #572409, rev 3.4, DNV60
+	 * - Ice Lake Xeon D document #714070, ICXD65
+	 * - Snowridge document #731931, SNR44
+	 */
+	.setup = PTR_IF(false, dnv_setup),
+	.exit = PTR_IF(false, dnv_exit),
 };
 
 static const struct pci_device_id pci_ids[] = {

[PATCH 5.15.y 1/2] serial: 8250_mid: Remove 8250_pci usage

[Sasha Levin]

From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

[ Upstream commit a136abd7e7abe0f1247f8ffde6cc7c8ab09f985b ]

8250_mid uses FL_*BASE* from linux/8250_pci.h and nothing else. The
code can be simplified by directly defining BARs within the driver
instead.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230915094336.13278-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/8250/8250_mid.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index e6c1791609ddf3..220857a45ac2d3 100644
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -12,7 +12,6 @@
 #include <linux/rational.h>
 
 #include <linux/dma/hsu.h>
-#include <linux/8250_pci.h>
 
 #include "8250.h"
 
@@ -32,9 +31,9 @@
 struct mid8250;
 
 struct mid8250_board {
-	unsigned int flags;
 	unsigned long freq;
 	unsigned int base_baud;
+	unsigned int bar;
 	int (*setup)(struct mid8250 *, struct uart_port *p);
 	void (*exit)(struct mid8250 *);
 };
@@ -169,7 +168,6 @@ static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
 {
 	struct hsu_dma_chip *chip = &mid->dma_chip;
 	struct pci_dev *pdev = to_pci_dev(p->dev);
-	unsigned int bar = FL_GET_BASE(mid->board->flags);
 	int ret;
 
 	pci_set_master(pdev);
@@ -183,7 +181,7 @@ static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
 	chip->dev = &pdev->dev;
 	chip->irq = pci_irq_vector(pdev, 0);
 	chip->regs = p->membase;
-	chip->length = pci_resource_len(pdev, bar);
+	chip->length = pci_resource_len(pdev, mid->board->bar);
 	chip->offset = DNV_DMA_CHAN_OFFSET;
 
 	/* Falling back to PIO mode if DMA probing fails */
@@ -292,7 +290,6 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct uart_8250_port uart;
 	struct mid8250 *mid;
-	unsigned int bar;
 	int ret;
 
 	ret = pcim_enable_device(pdev);
@@ -304,7 +301,6 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		return -ENOMEM;
 
 	mid->board = (struct mid8250_board *)id->driver_data;
-	bar = FL_GET_BASE(mid->board->flags);
 
 	memset(&uart, 0, sizeof(struct uart_8250_port));
 
@@ -317,8 +313,8 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 	uart.port.set_termios = mid8250_set_termios;
 
-	uart.port.mapbase = pci_resource_start(pdev, bar);
-	uart.port.membase = pcim_iomap(pdev, bar, 0);
+	uart.port.mapbase = pci_resource_start(pdev, mid->board->bar);
+	uart.port.membase = pcim_iomap(pdev, mid->board->bar, 0);
 	if (!uart.port.membase)
 		return -ENOMEM;
 
@@ -356,25 +352,25 @@ static void mid8250_remove(struct pci_dev *pdev)
 }
 
 static const struct mid8250_board pnw_board = {
-	.flags = FL_BASE0,
 	.freq = 50000000,
 	.base_baud = 115200,
+	.bar = 0,
 	.setup = pnw_setup,
 	.exit = pnw_exit,
 };
 
 static const struct mid8250_board tng_board = {
-	.flags = FL_BASE0,
 	.freq = 38400000,
 	.base_baud = 1843200,
+	.bar = 0,
 	.setup = tng_setup,
 	.exit = tng_exit,
 };
 
 static const struct mid8250_board dnv_board = {
-	.flags = FL_BASE1,
 	.freq = 133333333,
 	.base_baud = 115200,
+	.bar = 1,
 	.setup = dnv_setup,
 	.exit = dnv_exit,
 };
-- 
2.53.0

[PATCH 5.15.y 2/2] serial: 8250_mid: Disable DMA for selected platforms

[Sasha Levin]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit b1b4efea05a56c0995e4702a86d6624b4fdff32f ]

In accordance with Errata (specification updates)
HSUART May Stop Functioning when DMA is Active.

- Denverton document #572409, rev 3.4, DNV60
- Ice Lake Xeon D document #714070, ICXD65
- Snowridge document #731931, SNR44

For a quick fix just disable the respective callbacks during the device probe.
Depending on the future development we might remove them completely.

Reported-by: micas-opensource <zjianan156@gmail.com>
Closes: https://lore.kernel.org/linux-serial/20250625031409.2404219-1-opensource@ruijie.com.cn/
Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260626094937.561776-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/8250/8250_mid.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index 220857a45ac2d3..9a4c6466ab026d 100644
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/rational.h>
+#include <linux/util_macros.h>
 
 #include <linux/dma/hsu.h>
 
@@ -371,8 +372,16 @@ static const struct mid8250_board dnv_board = {
 	.freq = 133333333,
 	.base_baud = 115200,
 	.bar = 1,
-	.setup = dnv_setup,
-	.exit = dnv_exit,
+	/*
+	 * Errata:
+	 * HSUART May Stop Functioning when DMA is Active.
+	 *
+	 * - Denverton document #572409, rev 3.4, DNV60
+	 * - Ice Lake Xeon D document #714070, ICXD65
+	 * - Snowridge document #731931, SNR44
+	 */
+	.setup = PTR_IF(false, dnv_setup),
+	.exit = PTR_IF(false, dnv_exit),
 };
 
 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
-- 
2.53.0