Only AES use DMA in AT91SAM9G45 (TDES and SHA use PDC).
However latest Atmel TDES and SHA IP releases use DMA instead of PDC.
--> Atmel TDES and SHA drivers need DMA platform data for those IP releases.
Goal of this patch is to use the same platform data structure for all Atmel
crypto peripherals. This structure contains information about DMA interface.
Signed-off-by: Nicolas Royer <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
Acked-by: Eric Bénard <[email protected]>
Tested-by: Eric Bénard <[email protected]>
---
arch/arm/mach-at91/at91sam9g45_devices.c | 8 ++++----
include/linux/platform_data/atmel-aes.h | 22 ----------------------
include/linux/platform_data/crypto-atmel.h | 22 ++++++++++++++++++++++
3 files changed, 26 insertions(+), 26 deletions(-)
delete mode 100644 include/linux/platform_data/atmel-aes.h
create mode 100644 include/linux/platform_data/crypto-atmel.h
diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index fcd233c..a48dcb4 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -18,7 +18,7 @@
#include <linux/platform_device.h>
#include <linux/i2c-gpio.h>
#include <linux/atmel-mci.h>
-#include <linux/platform_data/atmel-aes.h>
+#include <linux/platform_data/crypto-atmel.h>
#include <linux/platform_data/at91_adc.h>
@@ -1900,7 +1900,7 @@ static void __init at91_add_device_tdes(void) {}
* -------------------------------------------------------------------- */
#if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
-static struct aes_platform_data aes_data;
+static struct crypto_platform_data aes_data;
static u64 aes_dmamask = DMA_BIT_MASK(32);
static struct resource aes_resources[] = {
@@ -1931,9 +1931,9 @@ static struct platform_device at91sam9g45_aes_device = {
static void __init at91_add_device_aes(void)
{
struct at_dma_slave *atslave;
- struct aes_dma_data *alt_atslave;
+ struct crypto_dma_data *alt_atslave;
- alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
+ alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
/* DMA TX slave channel configuration */
atslave = &alt_atslave->txdata;
diff --git a/include/linux/platform_data/atmel-aes.h b/include/linux/platform_data/atmel-aes.h
deleted file mode 100644
index ab68082..0000000
--- a/include/linux/platform_data/atmel-aes.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#ifndef __LINUX_ATMEL_AES_H
-#define __LINUX_ATMEL_AES_H
-
-#include <linux/platform_data/dma-atmel.h>
-
-/**
- * struct aes_dma_data - DMA data for AES
- */
-struct aes_dma_data {
- struct at_dma_slave txdata;
- struct at_dma_slave rxdata;
-};
-
-/**
- * struct aes_platform_data - board-specific AES configuration
- * @dma_slave: DMA slave interface to use in data transfers.
- */
-struct aes_platform_data {
- struct aes_dma_data *dma_slave;
-};
-
-#endif /* __LINUX_ATMEL_AES_H */
diff --git a/include/linux/platform_data/crypto-atmel.h b/include/linux/platform_data/crypto-atmel.h
new file mode 100644
index 0000000..b46e0d9
--- /dev/null
+++ b/include/linux/platform_data/crypto-atmel.h
@@ -0,0 +1,22 @@
+#ifndef __LINUX_CRYPTO_ATMEL_H
+#define __LINUX_CRYPTO_ATMEL_H
+
+#include <linux/platform_data/dma-atmel.h>
+
+/**
+ * struct crypto_dma_data - DMA data for AES/TDES/SHA
+ */
+struct crypto_dma_data {
+ struct at_dma_slave txdata;
+ struct at_dma_slave rxdata;
+};
+
+/**
+ * struct crypto_platform_data - board-specific AES/TDES/SHA configuration
+ * @dma_slave: DMA slave interface to use in data transfers.
+ */
+struct crypto_platform_data {
+ struct crypto_dma_data *dma_slave;
+};
+
+#endif /* __LINUX_CRYPTO_ATMEL_H */
--
1.7.6.5
Only AES use DMA in AT91SAM9G45 (TDES and SHA use PDC).
However latest Atmel TDES and SHA IP releases use DMA instead of PDC.
--> Atmel TDES and SHA drivers need DMA platform data for those IP releases.
Goal of this patch is to use the same platform data structure for all Atmel
crypto peripherals. This structure contains information about DMA interface.
Signed-off-by: Nicolas Royer <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
Acked-by: Eric Bénard <[email protected]>
Tested-by: Eric Bénard <[email protected]>
---
v2 : check kzalloc return value.
arch/arm/mach-at91/at91sam9g45_devices.c | 10 ++++++----
include/linux/platform_data/atmel-aes.h | 22 ----------------------
include/linux/platform_data/crypto-atmel.h | 22 ++++++++++++++++++++++
3 files changed, 28 insertions(+), 26 deletions(-)
delete mode 100644 include/linux/platform_data/atmel-aes.h
create mode 100644 include/linux/platform_data/crypto-atmel.h
diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index fcd233c..c1631d1 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -18,7 +18,7 @@
#include <linux/platform_device.h>
#include <linux/i2c-gpio.h>
#include <linux/atmel-mci.h>
-#include <linux/platform_data/atmel-aes.h>
+#include <linux/platform_data/crypto-atmel.h>
#include <linux/platform_data/at91_adc.h>
@@ -1900,7 +1900,7 @@ static void __init at91_add_device_tdes(void) {}
* -------------------------------------------------------------------- */
#if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
-static struct aes_platform_data aes_data;
+static struct crypto_platform_data aes_data;
static u64 aes_dmamask = DMA_BIT_MASK(32);
static struct resource aes_resources[] = {
@@ -1931,9 +1931,11 @@ static struct platform_device at91sam9g45_aes_device = {
static void __init at91_add_device_aes(void)
{
struct at_dma_slave *atslave;
- struct aes_dma_data *alt_atslave;
+ struct crypto_dma_data *alt_atslave;
- alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
+ alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
+ if (!alt_atslave)
+ panic("Unable to allocate memory for AES crypto_dma_data structure\n");
/* DMA TX slave channel configuration */
atslave = &alt_atslave->txdata;
diff --git a/include/linux/platform_data/atmel-aes.h b/include/linux/platform_data/atmel-aes.h
deleted file mode 100644
index ab68082..0000000
--- a/include/linux/platform_data/atmel-aes.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#ifndef __LINUX_ATMEL_AES_H
-#define __LINUX_ATMEL_AES_H
-
-#include <linux/platform_data/dma-atmel.h>
-
-/**
- * struct aes_dma_data - DMA data for AES
- */
-struct aes_dma_data {
- struct at_dma_slave txdata;
- struct at_dma_slave rxdata;
-};
-
-/**
- * struct aes_platform_data - board-specific AES configuration
- * @dma_slave: DMA slave interface to use in data transfers.
- */
-struct aes_platform_data {
- struct aes_dma_data *dma_slave;
-};
-
-#endif /* __LINUX_ATMEL_AES_H */
diff --git a/include/linux/platform_data/crypto-atmel.h b/include/linux/platform_data/crypto-atmel.h
new file mode 100644
index 0000000..b46e0d9
--- /dev/null
+++ b/include/linux/platform_data/crypto-atmel.h
@@ -0,0 +1,22 @@
+#ifndef __LINUX_CRYPTO_ATMEL_H
+#define __LINUX_CRYPTO_ATMEL_H
+
+#include <linux/platform_data/dma-atmel.h>
+
+/**
+ * struct crypto_dma_data - DMA data for AES/TDES/SHA
+ */
+struct crypto_dma_data {
+ struct at_dma_slave txdata;
+ struct at_dma_slave rxdata;
+};
+
+/**
+ * struct crypto_platform_data - board-specific AES/TDES/SHA configuration
+ * @dma_slave: DMA slave interface to use in data transfers.
+ */
+struct crypto_platform_data {
+ struct crypto_dma_data *dma_slave;
+};
+
+#endif /* __LINUX_CRYPTO_ATMEL_H */
--
1.7.6.5
Hi Jean-Christophe,
Le Wed, 7 Nov 2012 16:26:15 +0100,
Jean-Christophe PLAGNIOL-VILLARD <[email protected]> a ?crit :
> > @@ -1931,9 +1931,9 @@ static struct platform_device at91sam9g45_aes_device = {
> > static void __init at91_add_device_aes(void)
> > {
> > struct at_dma_slave *atslave;
> > - struct aes_dma_data *alt_atslave;
> > + struct crypto_dma_data *alt_atslave;
> >
> > - alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
> > + alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
> we do not check the result of kzalloc ouch
>
> and why we allocate it?
>
for both remarks : that's the way it's done in at91_add_device_mci since
75305d768d296a07fd02df9af3e5de326df1c72e
A v2 will follow (and also a fix for at91_add_device_mci).
Eric
On 17:27 Wed 07 Nov , Nicolas Royer wrote:
> Only AES use DMA in AT91SAM9G45 (TDES and SHA use PDC).
>
> However latest Atmel TDES and SHA IP releases use DMA instead of PDC.
> --> Atmel TDES and SHA drivers need DMA platform data for those IP releases.
>
> Goal of this patch is to use the same platform data structure for all Atmel
> crypto peripherals. This structure contains information about DMA interface.
>
> Signed-off-by: Nicolas Royer <[email protected]>
> Acked-by: Nicolas Ferre <[email protected]>
> Acked-by: Eric B?nard <[email protected]>
> Tested-by: Eric B?nard <[email protected]>
> ---
> v2 : check kzalloc return value.
>
> arch/arm/mach-at91/at91sam9g45_devices.c | 10 ++++++----
> include/linux/platform_data/atmel-aes.h | 22 ----------------------
> include/linux/platform_data/crypto-atmel.h | 22 ++++++++++++++++++++++
> 3 files changed, 28 insertions(+), 26 deletions(-)
> delete mode 100644 include/linux/platform_data/atmel-aes.h
> create mode 100644 include/linux/platform_data/crypto-atmel.h
>
> diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
> index fcd233c..c1631d1 100644
> --- a/arch/arm/mach-at91/at91sam9g45_devices.c
> +++ b/arch/arm/mach-at91/at91sam9g45_devices.c
> @@ -18,7 +18,7 @@
> #include <linux/platform_device.h>
> #include <linux/i2c-gpio.h>
> #include <linux/atmel-mci.h>
> -#include <linux/platform_data/atmel-aes.h>
> +#include <linux/platform_data/crypto-atmel.h>
>
> #include <linux/platform_data/at91_adc.h>
>
> @@ -1900,7 +1900,7 @@ static void __init at91_add_device_tdes(void) {}
> * -------------------------------------------------------------------- */
>
> #if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
> -static struct aes_platform_data aes_data;
> +static struct crypto_platform_data aes_data;
> static u64 aes_dmamask = DMA_BIT_MASK(32);
>
> static struct resource aes_resources[] = {
> @@ -1931,9 +1931,11 @@ static struct platform_device at91sam9g45_aes_device = {
> static void __init at91_add_device_aes(void)
> {
> struct at_dma_slave *atslave;
> - struct aes_dma_data *alt_atslave;
> + struct crypto_dma_data *alt_atslave;
>
> - alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
> + alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
I still not understand why we need to allocate it
just declare it as static
Best Regards,
J.
On 17:59 Wed 07 Nov , Eric B?nard wrote:
> Hi Jean-Christophe,
>
> Le Wed, 7 Nov 2012 17:45:23 +0100,
> Jean-Christophe PLAGNIOL-VILLARD <[email protected]> a ?crit :
> > > @@ -1900,7 +1900,7 @@ static void __init at91_add_device_tdes(void) {}
> > > * -------------------------------------------------------------------- */
> > >
> > > #if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
> > > -static struct aes_platform_data aes_data;
> > > +static struct crypto_platform_data aes_data;
> > > static u64 aes_dmamask = DMA_BIT_MASK(32);
> > >
> > > static struct resource aes_resources[] = {
> > > @@ -1931,9 +1931,11 @@ static struct platform_device at91sam9g45_aes_device = {
> > > static void __init at91_add_device_aes(void)
> > > {
> > > struct at_dma_slave *atslave;
> > > - struct aes_dma_data *alt_atslave;
> > > + struct crypto_dma_data *alt_atslave;
> > >
> > > - alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
> > > + alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
> > I still not understand why we need to allocate it
> >
> > just declare it as static
> >
> last time we had some data static and you asked to alloc them (and
> didn't bother to answer why you required that :
> http://lkml.indiana.edu/hypermail/linux/kernel/1207.0/02779.html ), now
> you ask to declare static something which is allocated (and
> that's already done this way for the mci) : may you please explain why
> so that we get it the right way for next time ?
in the driver yes we write multi instance and generic code but in the platfrom I do not see why
Best Regards,
J.
Only AES use DMA in AT91SAM9G45 (TDES and SHA use PDC).
However latest Atmel TDES and SHA IP releases use DMA instead of PDC.
--> Atmel TDES and SHA drivers need DMA platform data for those IP releases.
Goal of this patch is to use the same platform data structure for all Atmel
crypto peripherals. This structure contains information about DMA interface.
Signed-off-by: Nicolas Royer <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
Acked-by: Eric Bénard <[email protected]>
Tested-by: Eric Bénard <[email protected]>
---
v2 : check kzalloc return value.
v3 : alt_atslave structure declared as static.
arch/arm/mach-at91/at91sam9g45_devices.c | 14 ++++++--------
include/linux/platform_data/atmel-aes.h | 22 ----------------------
include/linux/platform_data/crypto-atmel.h | 22 ++++++++++++++++++++++
3 files changed, 28 insertions(+), 30 deletions(-)
delete mode 100644 include/linux/platform_data/atmel-aes.h
create mode 100644 include/linux/platform_data/crypto-atmel.h
diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index fcd233c..1501e58 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -18,7 +18,7 @@
#include <linux/platform_device.h>
#include <linux/i2c-gpio.h>
#include <linux/atmel-mci.h>
-#include <linux/platform_data/atmel-aes.h>
+#include <linux/platform_data/crypto-atmel.h>
#include <linux/platform_data/at91_adc.h>
@@ -1900,7 +1900,8 @@ static void __init at91_add_device_tdes(void) {}
* -------------------------------------------------------------------- */
#if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
-static struct aes_platform_data aes_data;
+static struct crypto_platform_data aes_data;
+static struct crypto_dma_data alt_atslave;
static u64 aes_dmamask = DMA_BIT_MASK(32);
static struct resource aes_resources[] = {
@@ -1931,23 +1932,20 @@ static struct platform_device at91sam9g45_aes_device = {
static void __init at91_add_device_aes(void)
{
struct at_dma_slave *atslave;
- struct aes_dma_data *alt_atslave;
-
- alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
/* DMA TX slave channel configuration */
- atslave = &alt_atslave->txdata;
+ atslave = &alt_atslave.txdata;
atslave->dma_dev = &at_hdmac_device.dev;
atslave->cfg = ATC_FIFOCFG_ENOUGHSPACE | ATC_SRC_H2SEL_HW |
ATC_SRC_PER(AT_DMA_ID_AES_RX);
/* DMA RX slave channel configuration */
- atslave = &alt_atslave->rxdata;
+ atslave = &alt_atslave.rxdata;
atslave->dma_dev = &at_hdmac_device.dev;
atslave->cfg = ATC_FIFOCFG_ENOUGHSPACE | ATC_DST_H2SEL_HW |
ATC_DST_PER(AT_DMA_ID_AES_TX);
- aes_data.dma_slave = alt_atslave;
+ aes_data.dma_slave = &alt_atslave;
platform_device_register(&at91sam9g45_aes_device);
}
#else
diff --git a/include/linux/platform_data/atmel-aes.h b/include/linux/platform_data/atmel-aes.h
deleted file mode 100644
index ab68082..0000000
--- a/include/linux/platform_data/atmel-aes.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#ifndef __LINUX_ATMEL_AES_H
-#define __LINUX_ATMEL_AES_H
-
-#include <linux/platform_data/dma-atmel.h>
-
-/**
- * struct aes_dma_data - DMA data for AES
- */
-struct aes_dma_data {
- struct at_dma_slave txdata;
- struct at_dma_slave rxdata;
-};
-
-/**
- * struct aes_platform_data - board-specific AES configuration
- * @dma_slave: DMA slave interface to use in data transfers.
- */
-struct aes_platform_data {
- struct aes_dma_data *dma_slave;
-};
-
-#endif /* __LINUX_ATMEL_AES_H */
diff --git a/include/linux/platform_data/crypto-atmel.h b/include/linux/platform_data/crypto-atmel.h
new file mode 100644
index 0000000..b46e0d9
--- /dev/null
+++ b/include/linux/platform_data/crypto-atmel.h
@@ -0,0 +1,22 @@
+#ifndef __LINUX_CRYPTO_ATMEL_H
+#define __LINUX_CRYPTO_ATMEL_H
+
+#include <linux/platform_data/dma-atmel.h>
+
+/**
+ * struct crypto_dma_data - DMA data for AES/TDES/SHA
+ */
+struct crypto_dma_data {
+ struct at_dma_slave txdata;
+ struct at_dma_slave rxdata;
+};
+
+/**
+ * struct crypto_platform_data - board-specific AES/TDES/SHA configuration
+ * @dma_slave: DMA slave interface to use in data transfers.
+ */
+struct crypto_platform_data {
+ struct crypto_dma_data *dma_slave;
+};
+
+#endif /* __LINUX_CRYPTO_ATMEL_H */
--
1.7.6.5
On 17:32 Tue 06 Nov , Nicolas Royer wrote:
> Only AES use DMA in AT91SAM9G45 (TDES and SHA use PDC).
>
> However latest Atmel TDES and SHA IP releases use DMA instead of PDC.
> --> Atmel TDES and SHA drivers need DMA platform data for those IP releases.
>
> Goal of this patch is to use the same platform data structure for all Atmel
> crypto peripherals. This structure contains information about DMA interface.
>
> Signed-off-by: Nicolas Royer <[email protected]>
> Acked-by: Nicolas Ferre <[email protected]>
> Acked-by: Eric B?nard <[email protected]>
> Tested-by: Eric B?nard <[email protected]>
> ---
> arch/arm/mach-at91/at91sam9g45_devices.c | 8 ++++----
> include/linux/platform_data/atmel-aes.h | 22 ----------------------
> include/linux/platform_data/crypto-atmel.h | 22 ++++++++++++++++++++++
> 3 files changed, 26 insertions(+), 26 deletions(-)
> delete mode 100644 include/linux/platform_data/atmel-aes.h
> create mode 100644 include/linux/platform_data/crypto-atmel.h
>
> diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
> index fcd233c..a48dcb4 100644
> --- a/arch/arm/mach-at91/at91sam9g45_devices.c
> +++ b/arch/arm/mach-at91/at91sam9g45_devices.c
> @@ -18,7 +18,7 @@
> #include <linux/platform_device.h>
> #include <linux/i2c-gpio.h>
> #include <linux/atmel-mci.h>
> -#include <linux/platform_data/atmel-aes.h>
> +#include <linux/platform_data/crypto-atmel.h>
>
> #include <linux/platform_data/at91_adc.h>
>
> @@ -1900,7 +1900,7 @@ static void __init at91_add_device_tdes(void) {}
> * -------------------------------------------------------------------- */
>
> #if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
> -static struct aes_platform_data aes_data;
> +static struct crypto_platform_data aes_data;
> static u64 aes_dmamask = DMA_BIT_MASK(32);
>
> static struct resource aes_resources[] = {
> @@ -1931,9 +1931,9 @@ static struct platform_device at91sam9g45_aes_device = {
> static void __init at91_add_device_aes(void)
> {
> struct at_dma_slave *atslave;
> - struct aes_dma_data *alt_atslave;
> + struct crypto_dma_data *alt_atslave;
>
> - alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
> + alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
we do not check the result of kzalloc ouch
and why we allocate it?
Best Regards,
J.
J.
Hi Jean-Christophe,
Le Wed, 7 Nov 2012 17:45:23 +0100,
Jean-Christophe PLAGNIOL-VILLARD <[email protected]> a ?crit :
> > @@ -1900,7 +1900,7 @@ static void __init at91_add_device_tdes(void) {}
> > * -------------------------------------------------------------------- */
> >
> > #if defined(CONFIG_CRYPTO_DEV_ATMEL_AES) || defined(CONFIG_CRYPTO_DEV_ATMEL_AES_MODULE)
> > -static struct aes_platform_data aes_data;
> > +static struct crypto_platform_data aes_data;
> > static u64 aes_dmamask = DMA_BIT_MASK(32);
> >
> > static struct resource aes_resources[] = {
> > @@ -1931,9 +1931,11 @@ static struct platform_device at91sam9g45_aes_device = {
> > static void __init at91_add_device_aes(void)
> > {
> > struct at_dma_slave *atslave;
> > - struct aes_dma_data *alt_atslave;
> > + struct crypto_dma_data *alt_atslave;
> >
> > - alt_atslave = kzalloc(sizeof(struct aes_dma_data), GFP_KERNEL);
> > + alt_atslave = kzalloc(sizeof(struct crypto_dma_data), GFP_KERNEL);
> I still not understand why we need to allocate it
>
> just declare it as static
>
last time we had some data static and you asked to alloc them (and
didn't bother to answer why you required that :
http://lkml.indiana.edu/hypermail/linux/kernel/1207.0/02779.html ), now
you ask to declare static something which is allocated (and
that's already done this way for the mci) : may you please explain why
so that we get it the right way for next time ?
Thanks
Eric