This is a note to let you know that I've just added the patch titled
ARM: PL011: Fix DMA support
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-pl011-fix-dma-support.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 58ac1b3799799069d53f5bf95c093f2fe8dd3cc5 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Wed, 22 Nov 2023 18:15:03 +0100
Subject: ARM: PL011: Fix DMA support
From: Arnd Bergmann <arnd@xxxxxxxx>
commit 58ac1b3799799069d53f5bf95c093f2fe8dd3cc5 upstream.
Since there is no guarantee that the memory returned by
dma_alloc_coherent() is associated with a 'struct page', using the
architecture specific phys_to_page() is wrong, but using
virt_to_page() would be as well.
Stop using sg lists altogether and just use the *_single() functions
instead. This also simplifies the code a bit since the scatterlists in
this driver always have only one entry anyway.
https://lore.kernel.org/lkml/86db0fe5-930d-4cbb-bd7d-03367da38951@xxxxxxxxxxxxxxxx/
Use consistent names for dma buffers
gc: Add a commit log from the initial thread:
https://lore.kernel.org/lkml/86db0fe5-930d-4cbb-bd7d-03367da38951@xxxxxxxxxxxxxxxx/
Use consistent names for dma buffers
Fixes: cb06ff102e2d7 ("ARM: PL011: Add support for Rx DMA buffer polling.")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Tested-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231122171503.235649-1-gregory.clement@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/amba-pl011.c | 112 +++++++++++++++++++---------------------
1 file changed, 54 insertions(+), 58 deletions(-)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -227,17 +227,18 @@ static struct vendor_data vendor_zte = {
/* Deals with DMA transactions */
-struct pl011_sgbuf {
- struct scatterlist sg;
- char *buf;
+struct pl011_dmabuf {
+ dma_addr_t dma;
+ size_t len;
+ char *buf;
};
struct pl011_dmarx_data {
struct dma_chan *chan;
struct completion complete;
bool use_buf_b;
- struct pl011_sgbuf sgbuf_a;
- struct pl011_sgbuf sgbuf_b;
+ struct pl011_dmabuf dbuf_a;
+ struct pl011_dmabuf dbuf_b;
dma_cookie_t cookie;
bool running;
struct timer_list timer;
@@ -250,7 +251,8 @@ struct pl011_dmarx_data {
struct pl011_dmatx_data {
struct dma_chan *chan;
- struct scatterlist sg;
+ dma_addr_t dma;
+ size_t len;
char *buf;
bool queued;
};
@@ -371,32 +373,24 @@ static int pl011_fifo_to_tty(struct uart
#define PL011_DMA_BUFFER_SIZE PAGE_SIZE
-static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
+static int pl011_dmabuf_init(struct dma_chan *chan, struct pl011_dmabuf *db,
enum dma_data_direction dir)
{
- dma_addr_t dma_addr;
-
- sg->buf = dma_alloc_coherent(chan->device->dev,
- PL011_DMA_BUFFER_SIZE, &dma_addr, GFP_KERNEL);
- if (!sg->buf)
+ db->buf = dma_alloc_coherent(chan->device->dev, PL011_DMA_BUFFER_SIZE,
+ &db->dma, GFP_KERNEL);
+ if (!db->buf)
return -ENOMEM;
-
- sg_init_table(&sg->sg, 1);
- sg_set_page(&sg->sg, phys_to_page(dma_addr),
- PL011_DMA_BUFFER_SIZE, offset_in_page(dma_addr));
- sg_dma_address(&sg->sg) = dma_addr;
- sg_dma_len(&sg->sg) = PL011_DMA_BUFFER_SIZE;
+ db->len = PL011_DMA_BUFFER_SIZE;
return 0;
}
-static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
+static void pl011_dmabuf_free(struct dma_chan *chan, struct pl011_dmabuf *db,
enum dma_data_direction dir)
{
- if (sg->buf) {
+ if (db->buf) {
dma_free_coherent(chan->device->dev,
- PL011_DMA_BUFFER_SIZE, sg->buf,
- sg_dma_address(&sg->sg));
+ PL011_DMA_BUFFER_SIZE, db->buf, db->dma);
}
}
@@ -557,8 +551,8 @@ static void pl011_dma_tx_callback(void *
spin_lock_irqsave(&uap->port.lock, flags);
if (uap->dmatx.queued)
- dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
- DMA_TO_DEVICE);
+ dma_unmap_single(dmatx->chan->device->dev, dmatx->dma,
+ dmatx->len, DMA_TO_DEVICE);
dmacr = uap->dmacr;
uap->dmacr = dmacr & ~UART011_TXDMAE;
@@ -644,18 +638,19 @@ static int pl011_dma_tx_refill(struct ua
memcpy(&dmatx->buf[first], &xmit->buf[0], second);
}
- dmatx->sg.length = count;
-
- if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
+ dmatx->len = count;
+ dmatx->dma = dma_map_single(dma_dev->dev, dmatx->buf, count,
+ DMA_TO_DEVICE);
+ if (dmatx->dma == DMA_MAPPING_ERROR) {
uap->dmatx.queued = false;
dev_dbg(uap->port.dev, "unable to map TX DMA\n");
return -EBUSY;
}
- desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
+ desc = dmaengine_prep_slave_single(chan, dmatx->dma, dmatx->len, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
- dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
+ dma_unmap_single(dma_dev->dev, dmatx->dma, dmatx->len, DMA_TO_DEVICE);
uap->dmatx.queued = false;
/*
* If DMA cannot be used right now, we complete this
@@ -819,8 +814,8 @@ __acquires(&uap->port.lock)
dmaengine_terminate_async(uap->dmatx.chan);
if (uap->dmatx.queued) {
- dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
- DMA_TO_DEVICE);
+ dma_unmap_single(uap->dmatx.chan->device->dev, uap->dmatx.dma,
+ uap->dmatx.len, DMA_TO_DEVICE);
uap->dmatx.queued = false;
uap->dmacr &= ~UART011_TXDMAE;
pl011_write(uap->dmacr, uap, REG_DMACR);
@@ -834,15 +829,15 @@ static int pl011_dma_rx_trigger_dma(stru
struct dma_chan *rxchan = uap->dmarx.chan;
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_async_tx_descriptor *desc;
- struct pl011_sgbuf *sgbuf;
+ struct pl011_dmabuf *dbuf;
if (!rxchan)
return -EIO;
/* Start the RX DMA job */
- sgbuf = uap->dmarx.use_buf_b ?
- &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
- desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
+ dbuf = uap->dmarx.use_buf_b ?
+ &uap->dmarx.dbuf_b : &uap->dmarx.dbuf_a;
+ desc = dmaengine_prep_slave_single(rxchan, dbuf->dma, dbuf->len,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
/*
@@ -882,8 +877,8 @@ static void pl011_dma_rx_chars(struct ua
bool readfifo)
{
struct tty_port *port = &uap->port.state->port;
- struct pl011_sgbuf *sgbuf = use_buf_b ?
- &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
+ struct pl011_dmabuf *dbuf = use_buf_b ?
+ &uap->dmarx.dbuf_b : &uap->dmarx.dbuf_a;
int dma_count = 0;
u32 fifotaken = 0; /* only used for vdbg() */
@@ -892,7 +887,7 @@ static void pl011_dma_rx_chars(struct ua
if (uap->dmarx.poll_rate) {
/* The data can be taken by polling */
- dmataken = sgbuf->sg.length - dmarx->last_residue;
+ dmataken = dbuf->len - dmarx->last_residue;
/* Recalculate the pending size */
if (pending >= dmataken)
pending -= dmataken;
@@ -906,7 +901,7 @@ static void pl011_dma_rx_chars(struct ua
* Note that tty_insert_flip_buf() tries to take as many chars
* as it can.
*/
- dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken,
+ dma_count = tty_insert_flip_string(port, dbuf->buf + dmataken,
pending);
uap->port.icount.rx += dma_count;
@@ -917,7 +912,7 @@ static void pl011_dma_rx_chars(struct ua
/* Reset the last_residue for Rx DMA poll */
if (uap->dmarx.poll_rate)
- dmarx->last_residue = sgbuf->sg.length;
+ dmarx->last_residue = dbuf->len;
/*
* Only continue with trying to read the FIFO if all DMA chars have
@@ -954,8 +949,8 @@ static void pl011_dma_rx_irq(struct uart
{
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_chan *rxchan = dmarx->chan;
- struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
- &dmarx->sgbuf_b : &dmarx->sgbuf_a;
+ struct pl011_dmabuf *dbuf = dmarx->use_buf_b ?
+ &dmarx->dbuf_b : &dmarx->dbuf_a;
size_t pending;
struct dma_tx_state state;
enum dma_status dmastat;
@@ -977,7 +972,7 @@ static void pl011_dma_rx_irq(struct uart
pl011_write(uap->dmacr, uap, REG_DMACR);
uap->dmarx.running = false;
- pending = sgbuf->sg.length - state.residue;
+ pending = dbuf->len - state.residue;
BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
/* Then we terminate the transfer - we now know our residue */
dmaengine_terminate_all(rxchan);
@@ -1004,8 +999,8 @@ static void pl011_dma_rx_callback(void *
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_chan *rxchan = dmarx->chan;
bool lastbuf = dmarx->use_buf_b;
- struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
- &dmarx->sgbuf_b : &dmarx->sgbuf_a;
+ struct pl011_dmabuf *dbuf = dmarx->use_buf_b ?
+ &dmarx->dbuf_b : &dmarx->dbuf_a;
size_t pending;
struct dma_tx_state state;
int ret;
@@ -1023,7 +1018,7 @@ static void pl011_dma_rx_callback(void *
* the DMA irq handler. So we check the residue here.
*/
rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
- pending = sgbuf->sg.length - state.residue;
+ pending = dbuf->len - state.residue;
BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
/* Then we terminate the transfer - we now know our residue */
dmaengine_terminate_all(rxchan);
@@ -1075,16 +1070,16 @@ static void pl011_dma_rx_poll(struct tim
unsigned long flags = 0;
unsigned int dmataken = 0;
unsigned int size = 0;
- struct pl011_sgbuf *sgbuf;
+ struct pl011_dmabuf *dbuf;
int dma_count;
struct dma_tx_state state;
- sgbuf = dmarx->use_buf_b ? &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
+ dbuf = dmarx->use_buf_b ? &uap->dmarx.dbuf_b : &uap->dmarx.dbuf_a;
rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
if (likely(state.residue < dmarx->last_residue)) {
- dmataken = sgbuf->sg.length - dmarx->last_residue;
+ dmataken = dbuf->len - dmarx->last_residue;
size = dmarx->last_residue - state.residue;
- dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken,
+ dma_count = tty_insert_flip_string(port, dbuf->buf + dmataken,
size);
if (dma_count == size)
dmarx->last_residue = state.residue;
@@ -1131,7 +1126,7 @@ static void pl011_dma_startup(struct uar
return;
}
- sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
+ uap->dmatx.len = PL011_DMA_BUFFER_SIZE;
/* The DMA buffer is now the FIFO the TTY subsystem can use */
uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
@@ -1141,7 +1136,7 @@ static void pl011_dma_startup(struct uar
goto skip_rx;
/* Allocate and map DMA RX buffers */
- ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
+ ret = pl011_dmabuf_init(uap->dmarx.chan, &uap->dmarx.dbuf_a,
DMA_FROM_DEVICE);
if (ret) {
dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
@@ -1149,12 +1144,12 @@ static void pl011_dma_startup(struct uar
goto skip_rx;
}
- ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
+ ret = pl011_dmabuf_init(uap->dmarx.chan, &uap->dmarx.dbuf_b,
DMA_FROM_DEVICE);
if (ret) {
dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
"RX buffer B", ret);
- pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
+ pl011_dmabuf_free(uap->dmarx.chan, &uap->dmarx.dbuf_a,
DMA_FROM_DEVICE);
goto skip_rx;
}
@@ -1208,8 +1203,9 @@ static void pl011_dma_shutdown(struct ua
/* In theory, this should already be done by pl011_dma_flush_buffer */
dmaengine_terminate_all(uap->dmatx.chan);
if (uap->dmatx.queued) {
- dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
- DMA_TO_DEVICE);
+ dma_unmap_single(uap->dmatx.chan->device->dev,
+ uap->dmatx.dma, uap->dmatx.len,
+ DMA_TO_DEVICE);
uap->dmatx.queued = false;
}
@@ -1220,8 +1216,8 @@ static void pl011_dma_shutdown(struct ua
if (uap->using_rx_dma) {
dmaengine_terminate_all(uap->dmarx.chan);
/* Clean up the RX DMA */
- pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
- pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
+ pl011_dmabuf_free(uap->dmarx.chan, &uap->dmarx.dbuf_a, DMA_FROM_DEVICE);
+ pl011_dmabuf_free(uap->dmarx.chan, &uap->dmarx.dbuf_b, DMA_FROM_DEVICE);
if (uap->dmarx.poll_rate)
del_timer_sync(&uap->dmarx.timer);
uap->using_rx_dma = false;
Patches currently in stable-queue which might be from arnd@xxxxxxxx are
queue-5.4/arm-pl011-fix-dma-support.patch
