linux/drivers/dma/milbeaut-xdmac.c
Uwe Kleine-König 47ee210011 dmaengine: milbeaut-xdmac: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

There is an error path that has the above mentioned problem. This patch
only adds a more drastic error message. To properly fix it,
dmaengine_terminate_sync() must be known to have succeeded (or that it's
safe to not call it as other drivers seem to assume).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231105093415.3704633-8-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2023-11-24 18:32:30 +05:30

422 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0
//
// Copyright (C) 2019 Linaro Ltd.
// Copyright (C) 2019 Socionext Inc.
#include <linux/bits.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/bitfield.h>
#include "virt-dma.h"
/* global register */
#define M10V_XDACS 0x00
/* channel local register */
#define M10V_XDTBC 0x10
#define M10V_XDSSA 0x14
#define M10V_XDDSA 0x18
#define M10V_XDSAC 0x1C
#define M10V_XDDAC 0x20
#define M10V_XDDCC 0x24
#define M10V_XDDES 0x28
#define M10V_XDDPC 0x2C
#define M10V_XDDSD 0x30
#define M10V_XDACS_XE BIT(28)
#define M10V_DEFBS 0x3
#define M10V_DEFBL 0xf
#define M10V_XDSAC_SBS GENMASK(17, 16)
#define M10V_XDSAC_SBL GENMASK(11, 8)
#define M10V_XDDAC_DBS GENMASK(17, 16)
#define M10V_XDDAC_DBL GENMASK(11, 8)
#define M10V_XDDES_CE BIT(28)
#define M10V_XDDES_SE BIT(24)
#define M10V_XDDES_SA BIT(15)
#define M10V_XDDES_TF GENMASK(23, 20)
#define M10V_XDDES_EI BIT(1)
#define M10V_XDDES_TI BIT(0)
#define M10V_XDDSD_IS_MASK GENMASK(3, 0)
#define M10V_XDDSD_IS_NORMAL 0x8
#define MLB_XDMAC_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
struct milbeaut_xdmac_desc {
struct virt_dma_desc vd;
size_t len;
dma_addr_t src;
dma_addr_t dst;
};
struct milbeaut_xdmac_chan {
struct virt_dma_chan vc;
struct milbeaut_xdmac_desc *md;
void __iomem *reg_ch_base;
};
struct milbeaut_xdmac_device {
struct dma_device ddev;
void __iomem *reg_base;
struct milbeaut_xdmac_chan channels[];
};
static struct milbeaut_xdmac_chan *
to_milbeaut_xdmac_chan(struct virt_dma_chan *vc)
{
return container_of(vc, struct milbeaut_xdmac_chan, vc);
}
static struct milbeaut_xdmac_desc *
to_milbeaut_xdmac_desc(struct virt_dma_desc *vd)
{
return container_of(vd, struct milbeaut_xdmac_desc, vd);
}
/* mc->vc.lock must be held by caller */
static struct milbeaut_xdmac_desc *
milbeaut_xdmac_next_desc(struct milbeaut_xdmac_chan *mc)
{
struct virt_dma_desc *vd;
vd = vchan_next_desc(&mc->vc);
if (!vd) {
mc->md = NULL;
return NULL;
}
list_del(&vd->node);
mc->md = to_milbeaut_xdmac_desc(vd);
return mc->md;
}
/* mc->vc.lock must be held by caller */
static void milbeaut_chan_start(struct milbeaut_xdmac_chan *mc,
struct milbeaut_xdmac_desc *md)
{
u32 val;
/* Setup the channel */
val = md->len - 1;
writel_relaxed(val, mc->reg_ch_base + M10V_XDTBC);
val = md->src;
writel_relaxed(val, mc->reg_ch_base + M10V_XDSSA);
val = md->dst;
writel_relaxed(val, mc->reg_ch_base + M10V_XDDSA);
val = readl_relaxed(mc->reg_ch_base + M10V_XDSAC);
val &= ~(M10V_XDSAC_SBS | M10V_XDSAC_SBL);
val |= FIELD_PREP(M10V_XDSAC_SBS, M10V_DEFBS) |
FIELD_PREP(M10V_XDSAC_SBL, M10V_DEFBL);
writel_relaxed(val, mc->reg_ch_base + M10V_XDSAC);
val = readl_relaxed(mc->reg_ch_base + M10V_XDDAC);
val &= ~(M10V_XDDAC_DBS | M10V_XDDAC_DBL);
val |= FIELD_PREP(M10V_XDDAC_DBS, M10V_DEFBS) |
FIELD_PREP(M10V_XDDAC_DBL, M10V_DEFBL);
writel_relaxed(val, mc->reg_ch_base + M10V_XDDAC);
/* Start the channel */
val = readl_relaxed(mc->reg_ch_base + M10V_XDDES);
val &= ~(M10V_XDDES_CE | M10V_XDDES_SE | M10V_XDDES_TF |
M10V_XDDES_EI | M10V_XDDES_TI);
val |= FIELD_PREP(M10V_XDDES_CE, 1) | FIELD_PREP(M10V_XDDES_SE, 1) |
FIELD_PREP(M10V_XDDES_TF, 1) | FIELD_PREP(M10V_XDDES_EI, 1) |
FIELD_PREP(M10V_XDDES_TI, 1);
writel_relaxed(val, mc->reg_ch_base + M10V_XDDES);
}
/* mc->vc.lock must be held by caller */
static void milbeaut_xdmac_start(struct milbeaut_xdmac_chan *mc)
{
struct milbeaut_xdmac_desc *md;
md = milbeaut_xdmac_next_desc(mc);
if (md)
milbeaut_chan_start(mc, md);
}
static irqreturn_t milbeaut_xdmac_interrupt(int irq, void *dev_id)
{
struct milbeaut_xdmac_chan *mc = dev_id;
struct milbeaut_xdmac_desc *md;
u32 val;
spin_lock(&mc->vc.lock);
/* Ack and Stop */
val = FIELD_PREP(M10V_XDDSD_IS_MASK, 0x0);
writel_relaxed(val, mc->reg_ch_base + M10V_XDDSD);
md = mc->md;
if (!md)
goto out;
vchan_cookie_complete(&md->vd);
milbeaut_xdmac_start(mc);
out:
spin_unlock(&mc->vc.lock);
return IRQ_HANDLED;
}
static void milbeaut_xdmac_free_chan_resources(struct dma_chan *chan)
{
vchan_free_chan_resources(to_virt_chan(chan));
}
static struct dma_async_tx_descriptor *
milbeaut_xdmac_prep_memcpy(struct dma_chan *chan, dma_addr_t dst,
dma_addr_t src, size_t len, unsigned long flags)
{
struct virt_dma_chan *vc = to_virt_chan(chan);
struct milbeaut_xdmac_desc *md;
md = kzalloc(sizeof(*md), GFP_NOWAIT);
if (!md)
return NULL;
md->len = len;
md->src = src;
md->dst = dst;
return vchan_tx_prep(vc, &md->vd, flags);
}
static int milbeaut_xdmac_terminate_all(struct dma_chan *chan)
{
struct virt_dma_chan *vc = to_virt_chan(chan);
struct milbeaut_xdmac_chan *mc = to_milbeaut_xdmac_chan(vc);
unsigned long flags;
u32 val;
LIST_HEAD(head);
spin_lock_irqsave(&vc->lock, flags);
/* Halt the channel */
val = readl(mc->reg_ch_base + M10V_XDDES);
val &= ~M10V_XDDES_CE;
val |= FIELD_PREP(M10V_XDDES_CE, 0);
writel(val, mc->reg_ch_base + M10V_XDDES);
if (mc->md) {
vchan_terminate_vdesc(&mc->md->vd);
mc->md = NULL;
}
vchan_get_all_descriptors(vc, &head);
spin_unlock_irqrestore(&vc->lock, flags);
vchan_dma_desc_free_list(vc, &head);
return 0;
}
static void milbeaut_xdmac_synchronize(struct dma_chan *chan)
{
vchan_synchronize(to_virt_chan(chan));
}
static void milbeaut_xdmac_issue_pending(struct dma_chan *chan)
{
struct virt_dma_chan *vc = to_virt_chan(chan);
struct milbeaut_xdmac_chan *mc = to_milbeaut_xdmac_chan(vc);
unsigned long flags;
spin_lock_irqsave(&vc->lock, flags);
if (vchan_issue_pending(vc) && !mc->md)
milbeaut_xdmac_start(mc);
spin_unlock_irqrestore(&vc->lock, flags);
}
static void milbeaut_xdmac_desc_free(struct virt_dma_desc *vd)
{
kfree(to_milbeaut_xdmac_desc(vd));
}
static int milbeaut_xdmac_chan_init(struct platform_device *pdev,
struct milbeaut_xdmac_device *mdev,
int chan_id)
{
struct device *dev = &pdev->dev;
struct milbeaut_xdmac_chan *mc = &mdev->channels[chan_id];
char *irq_name;
int irq, ret;
irq = platform_get_irq(pdev, chan_id);
if (irq < 0)
return irq;
irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-xdmac-%d",
chan_id);
if (!irq_name)
return -ENOMEM;
ret = devm_request_irq(dev, irq, milbeaut_xdmac_interrupt,
IRQF_SHARED, irq_name, mc);
if (ret)
return ret;
mc->reg_ch_base = mdev->reg_base + chan_id * 0x30;
mc->vc.desc_free = milbeaut_xdmac_desc_free;
vchan_init(&mc->vc, &mdev->ddev);
return 0;
}
static void enable_xdmac(struct milbeaut_xdmac_device *mdev)
{
unsigned int val;
val = readl(mdev->reg_base + M10V_XDACS);
val |= M10V_XDACS_XE;
writel(val, mdev->reg_base + M10V_XDACS);
}
static void disable_xdmac(struct milbeaut_xdmac_device *mdev)
{
unsigned int val;
val = readl(mdev->reg_base + M10V_XDACS);
val &= ~M10V_XDACS_XE;
writel(val, mdev->reg_base + M10V_XDACS);
}
static int milbeaut_xdmac_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct milbeaut_xdmac_device *mdev;
struct dma_device *ddev;
int nr_chans, ret, i;
nr_chans = platform_irq_count(pdev);
if (nr_chans < 0)
return nr_chans;
mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
GFP_KERNEL);
if (!mdev)
return -ENOMEM;
mdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(mdev->reg_base))
return PTR_ERR(mdev->reg_base);
ddev = &mdev->ddev;
ddev->dev = dev;
dma_cap_set(DMA_MEMCPY, ddev->cap_mask);
ddev->src_addr_widths = MLB_XDMAC_BUSWIDTHS;
ddev->dst_addr_widths = MLB_XDMAC_BUSWIDTHS;
ddev->device_free_chan_resources = milbeaut_xdmac_free_chan_resources;
ddev->device_prep_dma_memcpy = milbeaut_xdmac_prep_memcpy;
ddev->device_terminate_all = milbeaut_xdmac_terminate_all;
ddev->device_synchronize = milbeaut_xdmac_synchronize;
ddev->device_tx_status = dma_cookie_status;
ddev->device_issue_pending = milbeaut_xdmac_issue_pending;
INIT_LIST_HEAD(&ddev->channels);
for (i = 0; i < nr_chans; i++) {
ret = milbeaut_xdmac_chan_init(pdev, mdev, i);
if (ret)
return ret;
}
enable_xdmac(mdev);
ret = dma_async_device_register(ddev);
if (ret)
goto disable_xdmac;
ret = of_dma_controller_register(dev->of_node,
of_dma_simple_xlate, mdev);
if (ret)
goto unregister_dmac;
platform_set_drvdata(pdev, mdev);
return 0;
unregister_dmac:
dma_async_device_unregister(ddev);
disable_xdmac:
disable_xdmac(mdev);
return ret;
}
static void milbeaut_xdmac_remove(struct platform_device *pdev)
{
struct milbeaut_xdmac_device *mdev = platform_get_drvdata(pdev);
struct dma_chan *chan;
int ret;
/*
* Before reaching here, almost all descriptors have been freed by the
* ->device_free_chan_resources() hook. However, each channel might
* be still holding one descriptor that was on-flight at that moment.
* Terminate it to make sure this hardware is no longer running. Then,
* free the channel resources once again to avoid memory leak.
*/
list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
ret = dmaengine_terminate_sync(chan);
if (ret) {
/*
* This results in resource leakage and maybe also
* use-after-free errors as e.g. *mdev is kfreed.
*/
dev_alert(&pdev->dev, "Failed to terminate channel %d (%pe)\n",
chan->chan_id, ERR_PTR(ret));
return;
}
milbeaut_xdmac_free_chan_resources(chan);
}
of_dma_controller_free(pdev->dev.of_node);
dma_async_device_unregister(&mdev->ddev);
disable_xdmac(mdev);
}
static const struct of_device_id milbeaut_xdmac_match[] = {
{ .compatible = "socionext,milbeaut-m10v-xdmac" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, milbeaut_xdmac_match);
static struct platform_driver milbeaut_xdmac_driver = {
.probe = milbeaut_xdmac_probe,
.remove_new = milbeaut_xdmac_remove,
.driver = {
.name = "milbeaut-m10v-xdmac",
.of_match_table = milbeaut_xdmac_match,
},
};
module_platform_driver(milbeaut_xdmac_driver);
MODULE_DESCRIPTION("Milbeaut XDMAC DmaEngine driver");
MODULE_LICENSE("GPL v2");