diff mbox

[PATCH/RFC,1/5] mmc: renesas-sdhi, tmio: make dma more modular

Message ID 1493723743-22821-2-git-send-email-horms+renesas@verge.net.au (mailing list archive)
State New, archived
Headers show

Commit Message

Simon Horman May 2, 2017, 11:15 a.m. UTC 
Refactor DMA support to allow it to be provided by a set of call-backs
that are provided by a host driver. The motivation is to allow multiple
DMA implementations to be provided and instantiated at run-time.

Instantiate the existing DMA implementation from the sh_mobile_sdhi driver
which appears to match the current use-case. This has the side effect
of moving the DMA code from the tmio_core to the sh_mobile_sdhi driver.

A follow-up patch will change the source file for the SDHI DMA
implementation accordingly. Another follow-up patch will re-organise the
SDHI driver removing the need for tmio_mmc_get_dma_ops().

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/mmc/host/Makefile         |  3 +--
 drivers/mmc/host/sh_mobile_sdhi.c |  2 +-
 drivers/mmc/host/tmio_mmc.c       |  2 +-
 drivers/mmc/host/tmio_mmc.h       | 55 ++++++++++++++++-----------------------
 drivers/mmc/host/tmio_mmc_dma.c   | 24 +++++++++++++----
 drivers/mmc/host/tmio_mmc_pio.c   | 43 +++++++++++++++++++++++++++++-
 6 files changed, 86 insertions(+), 43 deletions(-)

Comments

Arnd Bergmann May 2, 2017, 12:01 p.m. UTC | #1 
On Tue, May 2, 2017 at 1:15 PM, Simon Horman <horms+renesas@verge.net.au> wrote:

> @@ -202,6 +214,15 @@ void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
>  void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
>  irqreturn_t tmio_mmc_irq(int irq, void *devid);
>
> +#if IS_ENABLED(CONFIG_MMC_SDHI)
> +const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void);
> +#else
> +static inline const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void)
> +{
> +       return NULL;
> +}
> +#endif
> +
>  static inline char *tmio_mmc_kmap_atomic(struct scatterlist *sg,
>                                          unsigned long *flags)
>  {

Here you return a NULL pointer for the operations structure

> +
> +static inline void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
> +{
> +       if (host->dma_ops->enable)
> +               host->dma_ops->enable(host, enable);
> +}
>

And here you check the ->enable callback but not the dma_ops pointer.
In the other callbacks you check the dma_ops pointer but not the callback.
Is that intentional? Maybe always check the dma_ops pointer first for
consistency, as a NULL operations structure (resulting from a future bug)
might lead running user space with kernel privileges.

      Arnd
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Simon Horman May 2, 2017, 12:57 p.m. UTC | #2 
On Tue, May 02, 2017 at 02:01:28PM +0200, Arnd Bergmann wrote:
> On Tue, May 2, 2017 at 1:15 PM, Simon Horman <horms+renesas@verge.net.au> wrote:
> 
> > @@ -202,6 +214,15 @@ void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
> >  void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
> >  irqreturn_t tmio_mmc_irq(int irq, void *devid);
> >
> > +#if IS_ENABLED(CONFIG_MMC_SDHI)
> > +const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void);
> > +#else
> > +static inline const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void)
> > +{
> > +       return NULL;
> > +}
> > +#endif
> > +
> >  static inline char *tmio_mmc_kmap_atomic(struct scatterlist *sg,
> >                                          unsigned long *flags)
> >  {
> 
> Here you return a NULL pointer for the operations structure
> 
> > +
> > +static inline void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
> > +{
> > +       if (host->dma_ops->enable)
> > +               host->dma_ops->enable(host, enable);
> > +}
> >
> 
> And here you check the ->enable callback but not the dma_ops pointer.
> In the other callbacks you check the dma_ops pointer but not the callback.
> Is that intentional? Maybe always check the dma_ops pointer first for
> consistency, as a NULL operations structure (resulting from a future bug)
> might lead running user space with kernel privileges.

Thanks for noticing.

I resolved that problem but it seems to have crept back in again.
I'll check to see how that happened.
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Simon Horman May 2, 2017, 1:03 p.m. UTC | #3 
On Tue, May 02, 2017 at 02:57:23PM +0200, Simon Horman wrote:
> On Tue, May 02, 2017 at 02:01:28PM +0200, Arnd Bergmann wrote:
> > On Tue, May 2, 2017 at 1:15 PM, Simon Horman <horms+renesas@verge.net.au> wrote:
> > 
> > > @@ -202,6 +214,15 @@ void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
> > >  void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
> > >  irqreturn_t tmio_mmc_irq(int irq, void *devid);
> > >
> > > +#if IS_ENABLED(CONFIG_MMC_SDHI)
> > > +const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void);
> > > +#else
> > > +static inline const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void)
> > > +{
> > > +       return NULL;
> > > +}
> > > +#endif
> > > +
> > >  static inline char *tmio_mmc_kmap_atomic(struct scatterlist *sg,
> > >                                          unsigned long *flags)
> > >  {
> > 
> > Here you return a NULL pointer for the operations structure
> > 
> > > +
> > > +static inline void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
> > > +{
> > > +       if (host->dma_ops->enable)
> > > +               host->dma_ops->enable(host, enable);
> > > +}
> > >
> > 
> > And here you check the ->enable callback but not the dma_ops pointer.
> > In the other callbacks you check the dma_ops pointer but not the callback.
> > Is that intentional? Maybe always check the dma_ops pointer first for
> > consistency, as a NULL operations structure (resulting from a future bug)
> > might lead running user space with kernel privileges.
> 
> Thanks for noticing.
> 
> I resolved that problem but it seems to have crept back in again.
> I'll check to see how that happened.

I take back my comment above - I fixed a different problem and it looks
like I sent out the latest local patches (phew!).

Regardless, I'll look into the problem you mention with a view to fixing it
in v2.
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diff mbox

Patch

diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 926347c2eeb4..f11b3d4b121d 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -37,8 +37,7 @@  obj-$(CONFIG_MMC_SDRICOH_CS)	+= sdricoh_cs.o
 obj-$(CONFIG_MMC_TMIO)		+= tmio_mmc.o
 obj-$(CONFIG_MMC_TMIO_CORE)	+= tmio_mmc_core.o
 tmio_mmc_core-y			:= tmio_mmc_pio.o
-tmio_mmc_core-$(subst m,y,$(CONFIG_MMC_SDHI))	+= tmio_mmc_dma.o
-obj-$(CONFIG_MMC_SDHI)		+= sh_mobile_sdhi.o
+obj-$(CONFIG_MMC_SDHI)		+= sh_mobile_sdhi.o tmio_mmc_dma.o
 obj-$(CONFIG_MMC_CB710)		+= cb710-mmc.o
 obj-$(CONFIG_MMC_VIA_SDMMC)	+= via-sdmmc.o
 obj-$(CONFIG_SDH_BFIN)		+= bfin_sdh.o
diff --git a/drivers/mmc/host/sh_mobile_sdhi.c b/drivers/mmc/host/sh_mobile_sdhi.c
index bc6be0dbea39..90ab460811f6 100644
--- a/drivers/mmc/host/sh_mobile_sdhi.c
+++ b/drivers/mmc/host/sh_mobile_sdhi.c
@@ -667,7 +667,7 @@  static int sh_mobile_sdhi_probe(struct platform_device *pdev)
 	/* All SDHI have SDIO status bits which must be 1 */
 	mmc_data->flags |= TMIO_MMC_SDIO_STATUS_SETBITS;
 
-	ret = tmio_mmc_host_probe(host, mmc_data);
+	ret = tmio_mmc_host_probe(host, mmc_data, tmio_mmc_get_dma_ops());
 	if (ret < 0)
 		goto efree;
 
diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
index e897e7fc3b14..0185b90ce0c5 100644
--- a/drivers/mmc/host/tmio_mmc.c
+++ b/drivers/mmc/host/tmio_mmc.c
@@ -99,7 +99,7 @@  static int tmio_mmc_probe(struct platform_device *pdev)
 	/* SD control register space size is 0x200, 0x400 for bus_shift=1 */
 	host->bus_shift = resource_size(res) >> 10;
 
-	ret = tmio_mmc_host_probe(host, pdata);
+	ret = tmio_mmc_host_probe(host, pdata, NULL);
 	if (ret)
 		goto host_free;
 
diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index d0edb5730d3f..7aeb945b50ac 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/drivers/mmc/host/tmio_mmc.h
@@ -115,6 +115,15 @@  struct tmio_mmc_dma {
 	void (*enable)(struct tmio_mmc_host *host, bool enable);
 };
 
+struct tmio_mmc_dma_ops {
+	void (*start)(struct tmio_mmc_host *host, struct mmc_data *data);
+	void (*enable)(struct tmio_mmc_host *host, bool enable);
+	void (*request)(struct tmio_mmc_host *host,
+			struct tmio_mmc_data *pdata);
+	void (*release)(struct tmio_mmc_host *host);
+	void (*abort)(struct tmio_mmc_host *host);
+};
+
 struct tmio_mmc_host {
 	void __iomem *ctl;
 	struct mmc_command      *cmd;
@@ -189,12 +198,15 @@  struct tmio_mmc_host {
 	/* Tuning values: 1 for success, 0 for failure */
 	DECLARE_BITMAP(taps, BITS_PER_BYTE * sizeof(long));
 	unsigned int tap_num;
+
+	const struct tmio_mmc_dma_ops *dma_ops;
 };
 
 struct tmio_mmc_host *tmio_mmc_host_alloc(struct platform_device *pdev);
 void tmio_mmc_host_free(struct tmio_mmc_host *host);
 int tmio_mmc_host_probe(struct tmio_mmc_host *host,
-			struct tmio_mmc_data *pdata);
+			struct tmio_mmc_data *pdata,
+			const struct tmio_mmc_dma_ops *dma_ops);
 void tmio_mmc_host_remove(struct tmio_mmc_host *host);
 void tmio_mmc_do_data_irq(struct tmio_mmc_host *host);
 
@@ -202,6 +214,15 @@  void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
 void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
 irqreturn_t tmio_mmc_irq(int irq, void *devid);
 
+#if IS_ENABLED(CONFIG_MMC_SDHI)
+const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void);
+#else
+static inline const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void)
+{
+	return NULL;
+}
+#endif
+
 static inline char *tmio_mmc_kmap_atomic(struct scatterlist *sg,
 					 unsigned long *flags)
 {
@@ -216,38 +237,6 @@  static inline void tmio_mmc_kunmap_atomic(struct scatterlist *sg,
 	local_irq_restore(*flags);
 }
 
-#if defined(CONFIG_MMC_SDHI) || defined(CONFIG_MMC_SDHI_MODULE)
-void tmio_mmc_start_dma(struct tmio_mmc_host *host, struct mmc_data *data);
-void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable);
-void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata);
-void tmio_mmc_release_dma(struct tmio_mmc_host *host);
-void tmio_mmc_abort_dma(struct tmio_mmc_host *host);
-#else
-static inline void tmio_mmc_start_dma(struct tmio_mmc_host *host,
-			       struct mmc_data *data)
-{
-}
-
-static inline void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
-{
-}
-
-static inline void tmio_mmc_request_dma(struct tmio_mmc_host *host,
-				 struct tmio_mmc_data *pdata)
-{
-	host->chan_tx = NULL;
-	host->chan_rx = NULL;
-}
-
-static inline void tmio_mmc_release_dma(struct tmio_mmc_host *host)
-{
-}
-
-static inline void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
-{
-}
-#endif
-
 #ifdef CONFIG_PM
 int tmio_mmc_host_runtime_suspend(struct device *dev);
 int tmio_mmc_host_runtime_resume(struct device *dev);
diff --git a/drivers/mmc/host/tmio_mmc_dma.c b/drivers/mmc/host/tmio_mmc_dma.c
index e2093db2b7ff..aa9b9b36bad2 100644
--- a/drivers/mmc/host/tmio_mmc_dma.c
+++ b/drivers/mmc/host/tmio_mmc_dma.c
@@ -22,7 +22,7 @@ 
 
 #define TMIO_MMC_MIN_DMA_LEN 8
 
-void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
+static void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
 {
 	if (!host->chan_tx || !host->chan_rx)
 		return;
@@ -31,7 +31,7 @@  void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
 		host->dma->enable(host, enable);
 }
 
-void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
+static void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
 {
 	tmio_mmc_enable_dma(host, false);
 
@@ -223,7 +223,7 @@  static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 	}
 }
 
-void tmio_mmc_start_dma(struct tmio_mmc_host *host,
+static void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 			       struct mmc_data *data)
 {
 	if (data->flags & MMC_DATA_READ) {
@@ -257,7 +257,8 @@  static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 		dma_async_issue_pending(chan);
 }
 
-void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
+static void tmio_mmc_request_dma(struct tmio_mmc_host *host,
+				 struct tmio_mmc_data *pdata)
 {
 	/* We can only either use DMA for both Tx and Rx or not use it at all */
 	if (!host->dma || (!host->pdev->dev.of_node &&
@@ -337,7 +338,7 @@  void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdat
 	host->chan_tx = NULL;
 }
 
-void tmio_mmc_release_dma(struct tmio_mmc_host *host)
+static void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 {
 	if (host->chan_tx) {
 		struct dma_chan *chan = host->chan_tx;
@@ -354,3 +355,16 @@  void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 		host->bounce_buf = NULL;
 	}
 }
+
+static const struct tmio_mmc_dma_ops tmio_mmc_dma_ops = {
+	.start = tmio_mmc_start_dma,
+	.enable = tmio_mmc_enable_dma,
+	.request = tmio_mmc_request_dma,
+	.release = tmio_mmc_release_dma,
+	.abort = tmio_mmc_abort_dma,
+};
+
+const struct tmio_mmc_dma_ops *tmio_mmc_get_dma_ops(void)
+{
+	return &tmio_mmc_dma_ops;
+}
diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index a2d92f10501b..96905c7187f0 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -52,17 +52,55 @@ 
 
 #include "tmio_mmc.h"
 
+static inline void tmio_mmc_start_dma(struct tmio_mmc_host *host,
+				      struct mmc_data *data)
+{
+	if (host->dma_ops)
+		host->dma_ops->start(host, data);
+}
+
+static inline void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
+{
+	if (host->dma_ops->enable)
+		host->dma_ops->enable(host, enable);
+}
+
+static inline void tmio_mmc_request_dma(struct tmio_mmc_host *host,
+					struct tmio_mmc_data *pdata)
+{
+	if (host->dma_ops) {
+		host->dma_ops->request(host, pdata);
+	} else {
+		host->chan_tx = NULL;
+		host->chan_rx = NULL;
+	}
+}
+
+static inline void tmio_mmc_release_dma(struct tmio_mmc_host *host)
+{
+	if (host->dma_ops)
+		host->dma_ops->release(host);
+}
+
+static inline void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
+{
+	if (host->dma_ops)
+		host->dma_ops->abort(host);
+}
+
 void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i)
 {
 	host->sdcard_irq_mask &= ~(i & TMIO_MASK_IRQ);
 	sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, host->sdcard_irq_mask);
 }
+EXPORT_SYMBOL(tmio_mmc_enable_mmc_irqs);
 
 void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i)
 {
 	host->sdcard_irq_mask |= (i & TMIO_MASK_IRQ);
 	sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, host->sdcard_irq_mask);
 }
+EXPORT_SYMBOL(tmio_mmc_disable_mmc_irqs);
 
 static void tmio_mmc_ack_mmc_irqs(struct tmio_mmc_host *host, u32 i)
 {
@@ -565,6 +603,7 @@  void tmio_mmc_do_data_irq(struct tmio_mmc_host *host)
 
 	schedule_work(&host->done);
 }
+EXPORT_SYMBOL(tmio_mmc_do_data_irq);
 
 static void tmio_mmc_data_irq(struct tmio_mmc_host *host, unsigned int stat)
 {
@@ -1140,7 +1179,8 @@  void tmio_mmc_host_free(struct tmio_mmc_host *host)
 EXPORT_SYMBOL(tmio_mmc_host_free);
 
 int tmio_mmc_host_probe(struct tmio_mmc_host *_host,
-			struct tmio_mmc_data *pdata)
+			struct tmio_mmc_data *pdata,
+			const struct tmio_mmc_dma_ops *dma_ops)
 {
 	struct platform_device *pdev = _host->pdev;
 	struct mmc_host *mmc = _host->mmc;
@@ -1252,6 +1292,7 @@  int tmio_mmc_host_probe(struct tmio_mmc_host *_host,
 	INIT_WORK(&_host->done, tmio_mmc_done_work);
 
 	/* See if we also get DMA */
+	_host->dma_ops = dma_ops;
 	tmio_mmc_request_dma(_host, pdata);
 
 	pm_runtime_set_active(&pdev->dev);