[PATCH mmc-next 0/3] solve SDHCI DWC MSHC 128MB DMA boundary limitation

[PATCH mmc-next 0/3] solve SDHCI DWC MSHC 128MB DMA boundary limitation

[Jisheng Zhang]

When using DMA, if the DMA addr spans 128MB boundary, we have to split
the DMA transfer into two so that each one doesn't exceed the boundary.

patch1 adds adma_table_num to struct sdhci_host so that driver can
control the ADMA table number.
patch2 introduces adma_write_desc() hook to struct sdhci_ops so that
driver can override it.
patch3 finally solves the 128MB boundary limitation.

Jisheng Zhang (3):
  mmc: sdhci: add adma_table_num member to struct sdhci_host
  mmc: sdhci: introduce adma_write_desc() hook to struct sdhci_ops
  mmc: sdhci-of-dwcmshc: solve 128MB DMA boundary limitation

 drivers/mmc/host/sdhci-of-dwcmshc.c | 41 ++++++++++++++++++++++++
 drivers/mmc/host/sdhci.c            | 48 +++++++++++++++++++----------
 drivers/mmc/host/sdhci.h            |  8 +++++
 3 files changed, 81 insertions(+), 16 deletions(-)

-- 
2.18.0

[PATCH mmc-next 1/3] mmc: sdhci: add adma_table_num member to struct sdhci_host

[Jisheng Zhang]

This patch adds adma_table_num member to struct sdhci_host to give more
flexibility to drivers to control the ADMA table number.

Default value of adma_table_num is set to (SDHCI_MAX_SEGS * 2 + 1).

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 drivers/mmc/host/sdhci.c | 17 +++++++++--------
 drivers/mmc/host/sdhci.h |  2 ++
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index a7b5602ef6f7..14dd4a49e03b 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3316,6 +3316,13 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev,
 
 	host->sdma_boundary = SDHCI_DEFAULT_BOUNDARY_ARG;
 
+	/*
+	 * The DMA descriptor table number is calculated as the maximum
+	 * number of segments times 2, to allow for an alignment
+	 * descriptor for each segment, plus 1 for a nop end descriptor.
+	 */
+	host->adma_table_num = SDHCI_MAX_SEGS * 2 + 1;
+
 	return host;
 }
 
@@ -3561,18 +3568,12 @@ int sdhci_setup_host(struct sdhci_host *host)
 		dma_addr_t dma;
 		void *buf;
 
-		/*
-		 * The DMA descriptor table size is calculated as the maximum
-		 * number of segments times 2, to allow for an alignment
-		 * descriptor for each segment, plus 1 for a nop end descriptor,
-		 * all multipled by the descriptor size.
-		 */
 		if (host->flags & SDHCI_USE_64_BIT_DMA) {
-			host->adma_table_sz = (SDHCI_MAX_SEGS * 2 + 1) *
+			host->adma_table_sz = host->adma_table_num *
 					      SDHCI_ADMA2_64_DESC_SZ;
 			host->desc_sz = SDHCI_ADMA2_64_DESC_SZ;
 		} else {
-			host->adma_table_sz = (SDHCI_MAX_SEGS * 2 + 1) *
+			host->adma_table_sz = host->adma_table_num *
 					      SDHCI_ADMA2_32_DESC_SZ;
 			host->desc_sz = SDHCI_ADMA2_32_DESC_SZ;
 		}
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 23966f887da6..d55fd7033e93 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -563,6 +563,8 @@ struct sdhci_host {
 	/* Host SDMA buffer boundary. */
 	u32			sdma_boundary;
 
+	u32			adma_table_num;
+
 	u64			data_timeout;
 
 	unsigned long private[0] ____cacheline_aligned;
-- 
2.18.0

[PATCH mmc-next 2/3] mmc: sdhci: introduce adma_write_desc() hook to struct sdhci_ops

[Jisheng Zhang]

Add this hook so that it can be overridden with driver specific
implementations. We also rename the original sdhci_adma_write_desc()
to _sdhci_adma_write_desc() and export it, so that it could be reused
by driver's specific implementations.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 drivers/mmc/host/sdhci.c | 31 +++++++++++++++++++++++--------
 drivers/mmc/host/sdhci.h |  6 ++++++
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 14dd4a49e03b..50c846d99182 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -554,8 +554,8 @@ static void sdhci_kunmap_atomic(void *buffer, unsigned long *flags)
 	local_irq_restore(*flags);
 }
 
-static void sdhci_adma_write_desc(struct sdhci_host *host, void *desc,
-				  dma_addr_t addr, int len, unsigned cmd)
+unsigned int _sdhci_adma_write_desc(struct sdhci_host *host, void *desc,
+				    dma_addr_t addr, int len, unsigned int cmd)
 {
 	struct sdhci_adma2_64_desc *dma_desc = desc;
 
@@ -566,6 +566,19 @@ static void sdhci_adma_write_desc(struct sdhci_host *host, void *desc,
 
 	if (host->flags & SDHCI_USE_64_BIT_DMA)
 		dma_desc->addr_hi = cpu_to_le32((u64)addr >> 32);
+
+	return host->desc_sz;
+}
+EXPORT_SYMBOL_GPL(_sdhci_adma_write_desc);
+
+static unsigned int sdhci_adma_write_desc(struct sdhci_host *host, void *desc,
+					  dma_addr_t addr, int len,
+					  unsigned int cmd)
+{
+	if (host->ops->adma_write_desc)
+		return host->ops->adma_write_desc(host, desc, addr, len, cmd);
+
+	return _sdhci_adma_write_desc(host, desc, addr, len, cmd);
 }
 
 static void sdhci_adma_mark_end(void *desc)
@@ -585,6 +598,7 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
 	void *desc, *align;
 	char *buffer;
 	int len, offset, i;
+	unsigned int desc_sz;
 
 	/*
 	 * The spec does not specify endianness of descriptor table.
@@ -618,15 +632,16 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
 			}
 
 			/* tran, valid */
-			sdhci_adma_write_desc(host, desc, align_addr, offset,
-					      ADMA2_TRAN_VALID);
+			desc_sz = sdhci_adma_write_desc(host, desc,
+							align_addr, offset,
+							ADMA2_TRAN_VALID);
 
 			BUG_ON(offset > 65536);
 
 			align += SDHCI_ADMA2_ALIGN;
 			align_addr += SDHCI_ADMA2_ALIGN;
 
-			desc += host->desc_sz;
+			desc += desc_sz;
 
 			addr += offset;
 			len -= offset;
@@ -636,9 +651,9 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
 
 		if (len) {
 			/* tran, valid */
-			sdhci_adma_write_desc(host, desc, addr, len,
-					      ADMA2_TRAN_VALID);
-			desc += host->desc_sz;
+			desc_sz = sdhci_adma_write_desc(host, desc, addr, len,
+							ADMA2_TRAN_VALID);
+			desc += desc_sz;
 		}
 
 		/*
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index d55fd7033e93..0aad0ee8f63b 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -605,6 +605,9 @@ struct sdhci_ops {
 	void    (*adma_workaround)(struct sdhci_host *host, u32 intmask);
 	void    (*card_event)(struct sdhci_host *host);
 	void	(*voltage_switch)(struct sdhci_host *host);
+	unsigned int	(*adma_write_desc)(struct sdhci_host *host, void *desc,
+					   dma_addr_t addr, int len,
+					   unsigned int cmd);
 };
 
 #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
@@ -735,6 +738,9 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios);
 int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 				      struct mmc_ios *ios);
 void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable);
+unsigned int _sdhci_adma_write_desc(struct sdhci_host *host, void *desc,
+				    dma_addr_t addr, int len,
+				    unsigned int cmd);
 
 #ifdef CONFIG_PM
 int sdhci_suspend_host(struct sdhci_host *host);
-- 
2.18.0

[PATCH mmc-next 3/3] mmc: sdhci-of-dwcmshc: solve 128MB DMA boundary limitation

[Jisheng Zhang]

When using DMA, if the DMA addr spans 128MB boundary, we have to split
the DMA transfer into two so that each one doesn't exceed the boundary.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 drivers/mmc/host/sdhci-of-dwcmshc.c | 41 +++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
index 1b7cd144fb01..01b5cb772554 100644
--- a/drivers/mmc/host/sdhci-of-dwcmshc.c
+++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
@@ -13,16 +13,45 @@
 
 #include "sdhci-pltfm.h"
 
+#define BOUNDARY_OK(addr, len) \
+	((addr | (SZ_128M - 1)) == ((addr + len) | (SZ_128M - 1)))
+
 struct dwcmshc_priv {
 	struct clk	*bus_clk;
 };
 
+/*
+ * if DMA addr spans 128MB boundary, we split the DMA transfer into two
+ * so that the DMA transfer doesn't exceed the boundary.
+ */
+static unsigned int dwcmshc_adma_write_desc(struct sdhci_host *host,
+					    void *desc, dma_addr_t addr,
+					    int len, unsigned int cmd)
+{
+	int tmplen, offset;
+
+	if (BOUNDARY_OK(addr, len))
+		return _sdhci_adma_write_desc(host, desc, addr, len, cmd);
+
+	offset = addr & (SZ_128M - 1);
+	tmplen = SZ_128M - offset;
+	_sdhci_adma_write_desc(host, desc, addr, tmplen, cmd);
+
+	addr += tmplen;
+	len -= tmplen;
+	desc += host->desc_sz;
+	_sdhci_adma_write_desc(host, desc, addr, len, cmd);
+
+	return host->desc_sz * 2;
+}
+
 static const struct sdhci_ops sdhci_dwcmshc_ops = {
 	.set_clock		= sdhci_set_clock,
 	.set_bus_width		= sdhci_set_bus_width,
 	.set_uhs_signaling	= sdhci_set_uhs_signaling,
 	.get_max_clock		= sdhci_pltfm_clk_get_max_clock,
 	.reset			= sdhci_reset,
+	.adma_write_desc	= dwcmshc_adma_write_desc,
 };
 
 static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = {
@@ -36,12 +65,24 @@ static int dwcmshc_probe(struct platform_device *pdev)
 	struct sdhci_host *host;
 	struct dwcmshc_priv *priv;
 	int err;
+	u32 extra;
 
 	host = sdhci_pltfm_init(pdev, &sdhci_dwcmshc_pdata,
 				sizeof(struct dwcmshc_priv));
 	if (IS_ERR(host))
 		return PTR_ERR(host);
 
+	/*
+	 * The DMA descriptor table number is calculated as the maximum
+	 * number of segments times 2, to allow for an alignment
+	 * descriptor for each segment, plus 1 for a nop end descriptor,
+	 * plus extra number for cross 128M boundary handling.
+	 */
+	extra = totalram_pages / (SZ_128M / PAGE_SIZE) + 1;
+	if (extra > SDHCI_MAX_SEGS)
+		extra = SDHCI_MAX_SEGS;
+	host->adma_table_num = SDHCI_MAX_SEGS * 2 + 1 + extra;
+
 	pltfm_host = sdhci_priv(host);
 	priv = sdhci_pltfm_priv(pltfm_host);
 
-- 
2.18.0

Re: [PATCH mmc-next 3/3] mmc: sdhci-of-dwcmshc: solve 128MB DMA boundary limitation

[Jisheng Zhang]

On Wed, 25 Jul 2018 17:47:49 +0800 Jisheng Zhang wrote:

> When using DMA, if the DMA addr spans 128MB boundary, we have to split
> the DMA transfer into two so that each one doesn't exceed the boundary.
> 
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
>  drivers/mmc/host/sdhci-of-dwcmshc.c | 41 +++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
> index 1b7cd144fb01..01b5cb772554 100644
> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
> @@ -13,16 +13,45 @@
>  
>  #include "sdhci-pltfm.h"
>  
> +#define BOUNDARY_OK(addr, len) \
> +	((addr | (SZ_128M - 1)) == ((addr + len) | (SZ_128M - 1)))

this should be
((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))

> +
>  struct dwcmshc_priv {
>  	struct clk	*bus_clk;
>  };
>  
> +/*
> + * if DMA addr spans 128MB boundary, we split the DMA transfer into two
> + * so that the DMA transfer doesn't exceed the boundary.
> + */
> +static unsigned int dwcmshc_adma_write_desc(struct sdhci_host *host,
> +					    void *desc, dma_addr_t addr,
> +					    int len, unsigned int cmd)
> +{
> +	int tmplen, offset;
> +
> +	if (BOUNDARY_OK(addr, len))
> +		return _sdhci_adma_write_desc(host, desc, addr, len, cmd);
> +
> +	offset = addr & (SZ_128M - 1);
> +	tmplen = SZ_128M - offset;
> +	_sdhci_adma_write_desc(host, desc, addr, tmplen, cmd);
> +
> +	addr += tmplen;
> +	len -= tmplen;
> +	desc += host->desc_sz;
> +	_sdhci_adma_write_desc(host, desc, addr, len, cmd);
> +
> +	return host->desc_sz * 2;
> +}
> +
>  static const struct sdhci_ops sdhci_dwcmshc_ops = {
>  	.set_clock		= sdhci_set_clock,
>  	.set_bus_width		= sdhci_set_bus_width,
>  	.set_uhs_signaling	= sdhci_set_uhs_signaling,
>  	.get_max_clock		= sdhci_pltfm_clk_get_max_clock,
>  	.reset			= sdhci_reset,
> +	.adma_write_desc	= dwcmshc_adma_write_desc,
>  };
>  
>  static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = {
> @@ -36,12 +65,24 @@ static int dwcmshc_probe(struct platform_device *pdev)
>  	struct sdhci_host *host;
>  	struct dwcmshc_priv *priv;
>  	int err;
> +	u32 extra;
>  
>  	host = sdhci_pltfm_init(pdev, &sdhci_dwcmshc_pdata,
>  				sizeof(struct dwcmshc_priv));
>  	if (IS_ERR(host))
>  		return PTR_ERR(host);
>  
> +	/*
> +	 * The DMA descriptor table number is calculated as the maximum
> +	 * number of segments times 2, to allow for an alignment
> +	 * descriptor for each segment, plus 1 for a nop end descriptor,
> +	 * plus extra number for cross 128M boundary handling.
> +	 */
> +	extra = totalram_pages / (SZ_128M / PAGE_SIZE) + 1;

will use DIV_ROUND_UP instead.

> +	if (extra > SDHCI_MAX_SEGS)
> +		extra = SDHCI_MAX_SEGS;
> +	host->adma_table_num = SDHCI_MAX_SEGS * 2 + 1 + extra;
> +
>  	pltfm_host = sdhci_priv(host);
>  	priv = sdhci_pltfm_priv(pltfm_host);
>