This patch intends to introduce "reverse-data" property at nvmem
provider side to reverse buffer.
For a case used from Ethernet driver, of_get_mac_address() may call
of_get_mac_addr_nvmem() to get MAC address from nvmem device. MAC address
programed in imx-ocopt is MSB first in lowest address, so need reverse
data then feedback to nvmem consumer. E.g. MAC address read from
imx-ocopt is 98:e2:06:9f:04:00, after reversed the data is
00:04:9f:06:e2:98.
Signed-off-by: Joakim Zhang <[email protected]>
---
drivers/nvmem/core.c | 30 ++++++++++++++++++++++++++++++
include/linux/nvmem-provider.h | 2 ++
2 files changed, 32 insertions(+)
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index b3bc30a04ed7..ccc2c5801c8e 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -55,6 +55,7 @@ struct nvmem_cell {
struct device_node *np;
struct nvmem_device *nvmem;
struct list_head node;
+ u32 flags;
};
static DEFINE_MUTEX(nvmem_mutex);
@@ -92,6 +93,26 @@ static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
return -EINVAL;
}
+static int nvmem_buffer_reverse(void *bufaddr, int len)
+{
+ u8 *buf = (u8 *)bufaddr;
+ u8 *temp;
+ int i;
+
+ temp = kzalloc(len, GFP_KERNEL);
+ if (!temp)
+ return -ENOMEM;
+
+ memcpy(temp, buf, len);
+
+ for (i = 0; i < len; i++)
+ buf[i] = temp[len - i - 1];
+
+ kfree(temp);
+
+ return 0;
+}
+
static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
unsigned int offset, void *val,
size_t bytes, int write)
@@ -705,6 +726,9 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
cell->bytes = be32_to_cpup(addr);
cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
+ if (of_property_read_bool(child, "reverse-data"))
+ cell->flags |= NVMEM_FLAGS_REVERSE_DATA;
+
addr = of_get_property(child, "bits", &len);
if (addr && len == (2 * sizeof(u32))) {
cell->bit_offset = be32_to_cpup(addr++);
@@ -1398,6 +1422,12 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
if (cell->bit_offset || cell->nbits)
nvmem_shift_read_buffer_in_place(cell, buf);
+ if (cell->flags & NVMEM_FLAGS_REVERSE_DATA) {
+ rc = nvmem_buffer_reverse(buf, cell->bytes);
+ if (rc < 0)
+ return rc;
+ }
+
if (len)
*len = cell->bytes;
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 104505e9028f..364ac2a61b11 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -31,6 +31,8 @@ enum nvmem_type {
#define NVMEM_DEVID_NONE (-1)
#define NVMEM_DEVID_AUTO (-2)
+#define NVMEM_FLAGS_REVERSE_DATA BIT(0)
+
/**
* struct nvmem_keepout - NVMEM register keepout range.
*
--
2.17.1
On 10/08/2021 08:35, Joakim Zhang wrote:
> This patch intends to introduce "reverse-data" property at nvmem
> provider side to reverse buffer.
>
> For a case used from Ethernet driver, of_get_mac_address() may call
> of_get_mac_addr_nvmem() to get MAC address from nvmem device. MAC address
> programed in imx-ocopt is MSB first in lowest address, so need reverse
Is all the data stored in imx-ocopt reverse byte order?
or someone decided to change the order for only mac-address?
> data then feedback to nvmem consumer. E.g. MAC address read from
> imx-ocopt is 98:e2:06:9f:04:00, after reversed the data is
> 00:04:9f:06:e2:98.
>
> Signed-off-by: Joakim Zhang <[email protected]>
> ---
> drivers/nvmem/core.c | 30 ++++++++++++++++++++++++++++++
> include/linux/nvmem-provider.h | 2 ++
> 2 files changed, 32 insertions(+)
>
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index b3bc30a04ed7..ccc2c5801c8e 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -55,6 +55,7 @@ struct nvmem_cell {
> struct device_node *np;
> struct nvmem_device *nvmem;
> struct list_head node;
> + u32 flags;
This flag also needs to go in struct nvmem_cell_info too.
> };
>
> static DEFINE_MUTEX(nvmem_mutex);
> @@ -92,6 +93,26 @@ static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
> return -EINVAL;
> }
>
> +static int nvmem_buffer_reverse(void *bufaddr, int len)
> +{
> + u8 *buf = (u8 *)bufaddr;
> + u8 *temp;
> + int i;
> +
> + temp = kzalloc(len, GFP_KERNEL);
> + if (!temp)
> + return -ENOMEM;
> +
> + memcpy(temp, buf, len);
> +
> + for (i = 0; i < len; i++)
> + buf[i] = temp[len - i - 1];
> +
You could possibly simplify this.
static void nvmem_buffer_reverse(u8 *buf, int len)
{
int i;
for (i = 0; i < len/2; i++)
swap(buf[i], buf[len - i - 1]);
}
> + kfree(temp);
> +
> + return 0;
> +}
> +
> static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
> unsigned int offset, void *val,
> size_t bytes, int write)
> @@ -705,6 +726,9 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
> cell->bytes = be32_to_cpup(addr);
> cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
>
> + if (of_property_read_bool(child, "reverse-data"))
> + cell->flags |= NVMEM_FLAGS_REVERSE_DATA;
> +
> addr = of_get_property(child, "bits", &len);
> if (addr && len == (2 * sizeof(u32))) {
> cell->bit_offset = be32_to_cpup(addr++);
> @@ -1398,6 +1422,12 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
> if (cell->bit_offset || cell->nbits)
> nvmem_shift_read_buffer_in_place(cell, buf);
>
> + if (cell->flags & NVMEM_FLAGS_REVERSE_DATA) {
> + rc = nvmem_buffer_reverse(buf, cell->bytes);
> + if (rc < 0)
> + return rc;
> + }
> +
> if (len)
> *len = cell->bytes;
>
> diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
> index 104505e9028f..364ac2a61b11 100644
> --- a/include/linux/nvmem-provider.h
> +++ b/include/linux/nvmem-provider.h
> @@ -31,6 +31,8 @@ enum nvmem_type {
> #define NVMEM_DEVID_NONE (-1)
> #define NVMEM_DEVID_AUTO (-2)
>
> +#define NVMEM_FLAGS_REVERSE_DATA BIT(0)
Maybe NVMEM_FLAGS_REVERSE_BYTE_ORDER and some kerneldoc would help new
users.
--srini
> +
> /**
> * struct nvmem_keepout - NVMEM register keepout range.
> *
>
> -----Original Message-----
> From: Srinivas Kandagatla <[email protected]>
> Sent: 2021年8月11日 17:52
> To: Joakim Zhang <[email protected]>; [email protected];
> [email protected]
> Cc: [email protected]; dl-linux-imx <[email protected]>;
> [email protected]; [email protected]
> Subject: Re: [PATCH V1 2/4] nvmem: core: introduce "reverse-data" property
> to reverse buffer
>
>
>
> On 10/08/2021 08:35, Joakim Zhang wrote:
> > This patch intends to introduce "reverse-data" property at nvmem
> > provider side to reverse buffer.
> >
> > For a case used from Ethernet driver, of_get_mac_address() may call
> > of_get_mac_addr_nvmem() to get MAC address from nvmem device. MAC
> > address programed in imx-ocopt is MSB first in lowest address, so need
> > reverse
>
> Is all the data stored in imx-ocopt reverse byte order?
No, it depends on how users program these data.
> or someone decided to change the order for only mac-address?
No, will not change the order for mac-address, would be consistent.
>
> > data then feedback to nvmem consumer. E.g. MAC address read from
> > imx-ocopt is 98:e2:06:9f:04:00, after reversed the data is
> > 00:04:9f:06:e2:98.
> >
> > Signed-off-by: Joakim Zhang <[email protected]>
> > ---
> > drivers/nvmem/core.c | 30
> ++++++++++++++++++++++++++++++
> > include/linux/nvmem-provider.h | 2 ++
> > 2 files changed, 32 insertions(+)
> >
> > diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index
> > b3bc30a04ed7..ccc2c5801c8e 100644
> > --- a/drivers/nvmem/core.c
> > +++ b/drivers/nvmem/core.c
> > @@ -55,6 +55,7 @@ struct nvmem_cell {
> > struct device_node *np;
> > struct nvmem_device *nvmem;
> > struct list_head node;
> > + u32 flags;
>
> This flag also needs to go in struct nvmem_cell_info too.
OK.
> > };
> >
> > static DEFINE_MUTEX(nvmem_mutex);
> > @@ -92,6 +93,26 @@ static int __nvmem_reg_write(struct nvmem_device
> *nvmem, unsigned int offset,
> > return -EINVAL;
> > }
> >
> > +static int nvmem_buffer_reverse(void *bufaddr, int len) {
> > + u8 *buf = (u8 *)bufaddr;
> > + u8 *temp;
> > + int i;
> > +
> > + temp = kzalloc(len, GFP_KERNEL);
> > + if (!temp)
> > + return -ENOMEM;
> > +
> > + memcpy(temp, buf, len);
> > +
> > + for (i = 0; i < len; i++)
> > + buf[i] = temp[len - i - 1];
> > +
>
> You could possibly simplify this.
>
> static void nvmem_buffer_reverse(u8 *buf, int len) {
> int i;
>
> for (i = 0; i < len/2; i++)
> swap(buf[i], buf[len - i - 1]);
> }
Thanks.
> > + kfree(temp);
> > +
> > + return 0;
> > +}
> > +
> > static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
> > unsigned int offset, void *val,
> > size_t bytes, int write)
> > @@ -705,6 +726,9 @@ static int nvmem_add_cells_from_of(struct
> nvmem_device *nvmem)
> > cell->bytes = be32_to_cpup(addr);
> > cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
> >
> > + if (of_property_read_bool(child, "reverse-data"))
> > + cell->flags |= NVMEM_FLAGS_REVERSE_DATA;
> > +
> > addr = of_get_property(child, "bits", &len);
> > if (addr && len == (2 * sizeof(u32))) {
> > cell->bit_offset = be32_to_cpup(addr++); @@ -1398,6
> +1422,12 @@
> > static int __nvmem_cell_read(struct nvmem_device *nvmem,
> > if (cell->bit_offset || cell->nbits)
> > nvmem_shift_read_buffer_in_place(cell, buf);
> >
> > + if (cell->flags & NVMEM_FLAGS_REVERSE_DATA) {
> > + rc = nvmem_buffer_reverse(buf, cell->bytes);
> > + if (rc < 0)
> > + return rc;
> > + }
> > +
> > if (len)
> > *len = cell->bytes;
> >
> > diff --git a/include/linux/nvmem-provider.h
> > b/include/linux/nvmem-provider.h index 104505e9028f..364ac2a61b11
> > 100644
> > --- a/include/linux/nvmem-provider.h
> > +++ b/include/linux/nvmem-provider.h
> > @@ -31,6 +31,8 @@ enum nvmem_type {
> > #define NVMEM_DEVID_NONE (-1)
> > #define NVMEM_DEVID_AUTO (-2)
> >
> > +#define NVMEM_FLAGS_REVERSE_DATA BIT(0)
>
> Maybe NVMEM_FLAGS_REVERSE_BYTE_ORDER and some kerneldoc would
> help new users.
Yes, will rename it, could you please point me where nvmem kerneldoc there to add new info?
Best Regards,
Joakim Zhang
> --srini
> > +
> > /**
> > * struct nvmem_keepout - NVMEM register keepout range.
> > *
> >