Re: [PATCH] hw/nvram: Avoid unnecessary Xilinx eFuse backstore write
On Wed, 26 Apr 2023 at 22:16, Tong Ho wrote: > > Add a check in the bit-set operation to write the backstore > only if the affected bit is 0 before. > > With this in place, there will be no need for callers to > do the checking in order to avoid unnecessary writes. > > Signed-off-by: Tong Ho > --- Applied to target-arm.next, thanks. -- PMM
Re: [PATCH] hw/nvram: Avoid unnecessary Xilinx eFuse backstore write
On 26/4/23 23:16, Tong Ho wrote: Add a check in the bit-set operation to write the backstore only if the affected bit is 0 before. With this in place, there will be no need for callers to do the checking in order to avoid unnecessary writes. Signed-off-by: Tong Ho --- hw/nvram/xlnx-efuse.c | 11 +-- 1 file changed, 9 insertions(+), 2 deletions(-) Reviewed-by: Philippe Mathieu-Daudé
Re: [PATCH] hw/nvram: Avoid unnecessary Xilinx eFuse backstore write
On [2023 Apr 26] Wed 14:16:07, Tong Ho wrote: > Add a check in the bit-set operation to write the backstore > only if the affected bit is 0 before. > > With this in place, there will be no need for callers to > do the checking in order to avoid unnecessary writes. > > Signed-off-by: Tong Ho Reviewed-by: Francisco Iglesias > --- > hw/nvram/xlnx-efuse.c | 11 +-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/hw/nvram/xlnx-efuse.c b/hw/nvram/xlnx-efuse.c > index fdfffaab99..655c40b8d1 100644 > --- a/hw/nvram/xlnx-efuse.c > +++ b/hw/nvram/xlnx-efuse.c > @@ -143,6 +143,8 @@ static bool efuse_ro_bits_find(XlnxEFuse *s, uint32_t k) > > bool xlnx_efuse_set_bit(XlnxEFuse *s, unsigned int bit) > { > +uint32_t set, *row; > + > if (efuse_ro_bits_find(s, bit)) { > g_autofree char *path = object_get_canonical_path(OBJECT(s)); > > @@ -152,8 +154,13 @@ bool xlnx_efuse_set_bit(XlnxEFuse *s, unsigned int bit) > return false; > } > > -s->fuse32[bit / 32] |= 1 << (bit % 32); > -efuse_bdrv_sync(s, bit); > +/* Avoid back-end write unless there is a real update */ > +row = >fuse32[bit / 32]; > +set = 1 << (bit % 32); > +if (!(set & *row)) { > +*row |= set; > +efuse_bdrv_sync(s, bit); > +} > return true; > } > > -- > 2.25.1 >
Re: [PATCH] hw/nvram: Avoid unnecessary Xilinx eFuse backstore write
On Thu, Apr 27, 2023 at 10:31 AM Tong Ho wrote: > > Add a check in the bit-set operation to write the backstore > only if the affected bit is 0 before. > > With this in place, there will be no need for callers to > do the checking in order to avoid unnecessary writes. > > Signed-off-by: Tong Ho Reviewed-by: Alistair Francis Alistair > --- > hw/nvram/xlnx-efuse.c | 11 +-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/hw/nvram/xlnx-efuse.c b/hw/nvram/xlnx-efuse.c > index fdfffaab99..655c40b8d1 100644 > --- a/hw/nvram/xlnx-efuse.c > +++ b/hw/nvram/xlnx-efuse.c > @@ -143,6 +143,8 @@ static bool efuse_ro_bits_find(XlnxEFuse *s, uint32_t k) > > bool xlnx_efuse_set_bit(XlnxEFuse *s, unsigned int bit) > { > +uint32_t set, *row; > + > if (efuse_ro_bits_find(s, bit)) { > g_autofree char *path = object_get_canonical_path(OBJECT(s)); > > @@ -152,8 +154,13 @@ bool xlnx_efuse_set_bit(XlnxEFuse *s, unsigned int bit) > return false; > } > > -s->fuse32[bit / 32] |= 1 << (bit % 32); > -efuse_bdrv_sync(s, bit); > +/* Avoid back-end write unless there is a real update */ > +row = >fuse32[bit / 32]; > +set = 1 << (bit % 32); > +if (!(set & *row)) { > +*row |= set; > +efuse_bdrv_sync(s, bit); > +} > return true; > } > > -- > 2.25.1 > >
[PATCH] hw/nvram: Avoid unnecessary Xilinx eFuse backstore write
Add a check in the bit-set operation to write the backstore only if the affected bit is 0 before. With this in place, there will be no need for callers to do the checking in order to avoid unnecessary writes. Signed-off-by: Tong Ho --- hw/nvram/xlnx-efuse.c | 11 +-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/hw/nvram/xlnx-efuse.c b/hw/nvram/xlnx-efuse.c index fdfffaab99..655c40b8d1 100644 --- a/hw/nvram/xlnx-efuse.c +++ b/hw/nvram/xlnx-efuse.c @@ -143,6 +143,8 @@ static bool efuse_ro_bits_find(XlnxEFuse *s, uint32_t k) bool xlnx_efuse_set_bit(XlnxEFuse *s, unsigned int bit) { +uint32_t set, *row; + if (efuse_ro_bits_find(s, bit)) { g_autofree char *path = object_get_canonical_path(OBJECT(s)); @@ -152,8 +154,13 @@ bool xlnx_efuse_set_bit(XlnxEFuse *s, unsigned int bit) return false; } -s->fuse32[bit / 32] |= 1 << (bit % 32); -efuse_bdrv_sync(s, bit); +/* Avoid back-end write unless there is a real update */ +row = >fuse32[bit / 32]; +set = 1 << (bit % 32); +if (!(set & *row)) { +*row |= set; +efuse_bdrv_sync(s, bit); +} return true; } -- 2.25.1