[PATCH] lightnvm: calculate device values correctly

[PATCH] lightnvm: calculate device values correctly

[Wenwei Tao]

In the original calculation, the relationships among
block, plane and lun was confusing, refine it on the
basis of Open-channelSSDInterfaceSpecification.

Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
---
 drivers/lightnvm/core.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index f659e60..1864b94 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -174,8 +174,8 @@ static int nvm_core_init(struct nvm_dev *dev)
 	dev->nr_chnls = grp->num_ch;
 	dev->luns_per_chnl = grp->num_lun;
 	dev->pgs_per_blk = grp->num_pg;
-	dev->blks_per_lun = grp->num_blk;
 	dev->nr_planes = grp->num_pln;
+	dev->blks_per_lun = grp->num_blk * grp->num_pln;
 	dev->sec_size = grp->csecs;
 	dev->oob_size = grp->sos;
 	dev->sec_per_pg = grp->fpg_sz / grp->csecs;
@@ -191,13 +191,12 @@ static int nvm_core_init(struct nvm_dev *dev)
 		dev->plane_mode = NVM_PLANE_QUAD;
 
 	/* calculated values */
-	dev->sec_per_pl = dev->sec_per_pg * dev->nr_planes;
-	dev->sec_per_blk = dev->sec_per_pl * dev->pgs_per_blk;
+	dev->sec_per_blk = dev->sec_per_pg * dev->pgs_per_blk;
+	dev->sec_per_pl = dev->sec_per_blk * grp->num_blk;
 	dev->sec_per_lun = dev->sec_per_blk * dev->blks_per_lun;
 	dev->nr_luns = dev->luns_per_chnl * dev->nr_chnls;
 
-	dev->total_blocks = dev->nr_planes *
-				dev->blks_per_lun *
+	dev->total_blocks = dev->blks_per_lun *
 				dev->luns_per_chnl *
 				dev->nr_chnls;
 	dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
-- 
1.9.1

Re: [PATCH] lightnvm: calculate device values correctly

[Wenwei Tao]

I'm a new guy to flash, if I'm wrong about this patch, please correct me.
Thanks.

2015-11-22 21:51 GMT+08:00 Wenwei Tao <ww.tao0320@gmail.com>:
> In the original calculation, the relationships among
> block, plane and lun was confusing, refine it on the
> basis of Open-channelSSDInterfaceSpecification.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
> ---
>  drivers/lightnvm/core.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index f659e60..1864b94 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -174,8 +174,8 @@ static int nvm_core_init(struct nvm_dev *dev)
>         dev->nr_chnls = grp->num_ch;
>         dev->luns_per_chnl = grp->num_lun;
>         dev->pgs_per_blk = grp->num_pg;
> -       dev->blks_per_lun = grp->num_blk;
>         dev->nr_planes = grp->num_pln;
> +       dev->blks_per_lun = grp->num_blk * grp->num_pln;
>         dev->sec_size = grp->csecs;
>         dev->oob_size = grp->sos;
>         dev->sec_per_pg = grp->fpg_sz / grp->csecs;
> @@ -191,13 +191,12 @@ static int nvm_core_init(struct nvm_dev *dev)
>                 dev->plane_mode = NVM_PLANE_QUAD;
>
>         /* calculated values */
> -       dev->sec_per_pl = dev->sec_per_pg * dev->nr_planes;
> -       dev->sec_per_blk = dev->sec_per_pl * dev->pgs_per_blk;
> +       dev->sec_per_blk = dev->sec_per_pg * dev->pgs_per_blk;
> +       dev->sec_per_pl = dev->sec_per_blk * grp->num_blk;
>         dev->sec_per_lun = dev->sec_per_blk * dev->blks_per_lun;
>         dev->nr_luns = dev->luns_per_chnl * dev->nr_chnls;
>
> -       dev->total_blocks = dev->nr_planes *
> -                               dev->blks_per_lun *
> +       dev->total_blocks = dev->blks_per_lun *
>                                 dev->luns_per_chnl *
>                                 dev->nr_chnls;
>         dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
> --
> 1.9.1
>

Re: [PATCH] lightnvm: calculate device values correctly

[Matias]

On 11/22/2015 02:51 PM, Wenwei Tao wrote:
> In the original calculation, the relationships among
> block, plane and lun was confusing, refine it on the
> basis of Open-channelSSDInterfaceSpecification.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
> ---
>   drivers/lightnvm/core.c | 9 ++++-----
>   1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index f659e60..1864b94 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -174,8 +174,8 @@ static int nvm_core_init(struct nvm_dev *dev)
>   	dev->nr_chnls = grp->num_ch;
>   	dev->luns_per_chnl = grp->num_lun;
>   	dev->pgs_per_blk = grp->num_pg;
> -	dev->blks_per_lun = grp->num_blk;
>   	dev->nr_planes = grp->num_pln;
> +	dev->blks_per_lun = grp->num_blk * grp->num_pln;
>   	dev->sec_size = grp->csecs;
>   	dev->oob_size = grp->sos;
>   	dev->sec_per_pg = grp->fpg_sz / grp->csecs;
> @@ -191,13 +191,12 @@ static int nvm_core_init(struct nvm_dev *dev)
>   		dev->plane_mode = NVM_PLANE_QUAD;
>
>   	/* calculated values */
> -	dev->sec_per_pl = dev->sec_per_pg * dev->nr_planes;
> -	dev->sec_per_blk = dev->sec_per_pl * dev->pgs_per_blk;
> +	dev->sec_per_blk = dev->sec_per_pg * dev->pgs_per_blk;
> +	dev->sec_per_pl = dev->sec_per_blk * grp->num_blk;
>   	dev->sec_per_lun = dev->sec_per_blk * dev->blks_per_lun;
>   	dev->nr_luns = dev->luns_per_chnl * dev->nr_chnls;
>
> -	dev->total_blocks = dev->nr_planes *
> -				dev->blks_per_lun *
> +	dev->total_blocks = dev->blks_per_lun *
>   				dev->luns_per_chnl *
>   				dev->nr_chnls;
>   	dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
>

The reason I had it as before, was because I wanted to drive the device 
in either single/double/quad read/write/erase plane mode. That way we 
could get away with only managing 1/4 or 1/2 of the block metadata.

What is your use case? It could make sense, but it will require a little 
more work to build up the framework for having the various modes. i.e. 
detect supported plane mode, make a explicit decision about which plane 
mode to always use (or dynamically) and afterwards allocate the 
appropriate data structures.

Re: [PATCH] lightnvm: calculate device values correctly

[Wenwei Tao]

OK, I see. Thanks for the explanation.

2015-11-23 2:34 GMT+08:00 Matias <mb@lightnvm.io>:
> On 11/22/2015 02:51 PM, Wenwei Tao wrote:
>>
>> In the original calculation, the relationships among
>> block, plane and lun was confusing, refine it on the
>> basis of Open-channelSSDInterfaceSpecification.
>>
>> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
>> ---
>>   drivers/lightnvm/core.c | 9 ++++-----
>>   1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
>> index f659e60..1864b94 100644
>> --- a/drivers/lightnvm/core.c
>> +++ b/drivers/lightnvm/core.c
>> @@ -174,8 +174,8 @@ static int nvm_core_init(struct nvm_dev *dev)
>>         dev->nr_chnls = grp->num_ch;
>>         dev->luns_per_chnl = grp->num_lun;
>>         dev->pgs_per_blk = grp->num_pg;
>> -       dev->blks_per_lun = grp->num_blk;
>>         dev->nr_planes = grp->num_pln;
>> +       dev->blks_per_lun = grp->num_blk * grp->num_pln;
>>         dev->sec_size = grp->csecs;
>>         dev->oob_size = grp->sos;
>>         dev->sec_per_pg = grp->fpg_sz / grp->csecs;
>> @@ -191,13 +191,12 @@ static int nvm_core_init(struct nvm_dev *dev)
>>                 dev->plane_mode = NVM_PLANE_QUAD;
>>
>>         /* calculated values */
>> -       dev->sec_per_pl = dev->sec_per_pg * dev->nr_planes;
>> -       dev->sec_per_blk = dev->sec_per_pl * dev->pgs_per_blk;
>> +       dev->sec_per_blk = dev->sec_per_pg * dev->pgs_per_blk;
>> +       dev->sec_per_pl = dev->sec_per_blk * grp->num_blk;
>>         dev->sec_per_lun = dev->sec_per_blk * dev->blks_per_lun;
>>         dev->nr_luns = dev->luns_per_chnl * dev->nr_chnls;
>>
>> -       dev->total_blocks = dev->nr_planes *
>> -                               dev->blks_per_lun *
>> +       dev->total_blocks = dev->blks_per_lun *
>>                                 dev->luns_per_chnl *
>>                                 dev->nr_chnls;
>>         dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
>>
>
> The reason I had it as before, was because I wanted to drive the device in
> either single/double/quad read/write/erase plane mode. That way we could get
> away with only managing 1/4 or 1/2 of the block metadata.
>
> What is your use case? It could make sense, but it will require a little
> more work to build up the framework for having the various modes. i.e.
> detect supported plane mode, make a explicit decision about which plane mode
> to always use (or dynamically) and afterwards allocate the appropriate data
> structures.