RE: [PATCH v10 3/5] CPM/QE: use genalloc to manage CPM/QE muram

Zhao Qiang
2015-09-22T08:10:35Z

On Tue, Sep 22, 2015 at 06:47 AM +0800, Wood Scott-B07421 wrote:
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, September 22, 2015 6:47 AM
> To: Zhao Qiang-B45475
> Cc: linux-kernel@vger.kernel.org; linuxppc-dev@lists.ozlabs.org;
> lauraa@codeaurora.org; Xie Xiaobo-R63061; benh@kernel.crashing.org; Li
> Yang-Leo-R58472; paulus@samba.org
> Subject: Re: [PATCH v10 3/5] CPM/QE: use genalloc to manage CPM/QE muram
>
> On Fri, Sep 18, 2015 at 03:15:19PM +0800, Zhao Qiang wrote:
> > Use genalloc to manage CPM/QE muram instead of rheap.
> >
> > Signed-off-by: Zhao Qiang <qiang.zhao@freescale.com>
> > ---
> > Changes for v9:
> > - splitted from patch 3/5, modify cpm muram management functions.
> > Changes for v10:
> > - modify cpm muram first, then move to qe_common
> > - modify commit.
> >
> > arch/powerpc/platforms/Kconfig | 1 +
> > arch/powerpc/sysdev/cpm_common.c | 150
> > +++++++++++++++++++++++++++------------
> > 2 files changed, 107 insertions(+), 44 deletions(-)
> >
> > diff --git a/arch/powerpc/platforms/Kconfig
> > b/arch/powerpc/platforms/Kconfig index b7f9c40..01f98a2 100644
> > --- a/arch/powerpc/platforms/Kconfig
> > +++ b/arch/powerpc/platforms/Kconfig
> > @@ -276,6 +276,7 @@ config QUICC_ENGINE
> > bool "Freescale QUICC Engine (QE) Support"
> > depends on FSL_SOC && PPC32
> > select PPC_LIB_RHEAP
> > + select GENERIC_ALLOCATOR
> > select CRC32
> > help
> > The QUICC Engine (QE) is a new generation of communications diff
> > --git a/arch/powerpc/sysdev/cpm_common.c
> > b/arch/powerpc/sysdev/cpm_common.c
> > index 4f78695..453d18c 100644
> > --- a/arch/powerpc/sysdev/cpm_common.c
> > +++ b/arch/powerpc/sysdev/cpm_common.c
> > @@ -17,6 +17,7 @@
> > * published by the Free Software Foundation.
> > */
> >
> > +#include <linux/genalloc.h>
> > #include <linux/init.h>
> > #include <linux/of_device.h>
> > #include <linux/spinlock.h>
> > @@ -27,7 +28,6 @@
> >
> > #include <asm/udbg.h>
> > #include <asm/io.h>
> > -#include <asm/rheap.h>
> > #include <asm/cpm.h>
> >
> > #include <mm/mmu_decl.h>
> > @@ -65,14 +65,24 @@ void __init udbg_init_cpm(void) } #endif
> >
> > +static struct gen_pool *muram_pool;
> > +static struct genpool_data_align muram_pool_data; static struct
> > +genpool_data_fixed muram_pool_data_fixed;
>
> Why are these global? If you keep the data local to the caller (and use
> gen_pool_alloc_data()) then you probably don't need cpm_muram_lock.

Ok

>
> > static spinlock_t cpm_muram_lock;
> > -static rh_block_t cpm_boot_muram_rh_block[16]; -static rh_info_t
> > cpm_muram_info; static u8 __iomem *muram_vbase; static phys_addr_t
> > muram_pbase;
> >
> > -/* Max address size we deal with */
> > +struct muram_block {
> > + struct list_head head;
> > + unsigned long start;
> > + int size;
> > +};
> > +
> > +static LIST_HEAD(muram_block_list);
> > +
> > +/* max address size we deal with */
> > #define OF_MAX_ADDR_CELLS 4
> > +#define GENPOOL_OFFSET 4096
>
> Is 4096 bytes the maximum alignment you'll ever need? Wouldn't it be
> safer to use a much larger offset?

Yes, 4096 is the maximum alignment I ever need.

>
> > int cpm_muram_init(void)
> > {
> > @@ -86,113 +96,165 @@ int cpm_muram_init(void)
> > if (muram_pbase)
> > return 0;
> >
> > - spin_lock_init(&cpm_muram_lock);
>
> Why are you eliminating the lock init, given that you're not getting rid
> of the lock?
>
> > - /* initialize the info header */
> > - rh_init(&cpm_muram_info, 1,
> > - sizeof(cpm_boot_muram_rh_block) /
> > - sizeof(cpm_boot_muram_rh_block[0]),
> > - cpm_boot_muram_rh_block);
> > -
> > np = of_find_compatible_node(NULL, NULL, "fsl,cpm-muram-data");
> > if (!np) {
> > /* try legacy bindings */
> > np = of_find_node_by_name(NULL, "data-only");
> > if (!np) {
> > - printk(KERN_ERR "Cannot find CPM muram data node");
> > + pr_err("Cannot find CPM muram data node");
> > ret = -ENODEV;
> > goto out;
> > }
> > }
> >
> > + muram_pool = gen_pool_create(1, -1);
>
> Do we really need byte-granularity?

It is 2byte-granularity, 4byte-granularity is needed

>
> > muram_pbase = of_translate_address(np, zero);
> > if (muram_pbase == (phys_addr_t)OF_BAD_ADDR) {
> > - printk(KERN_ERR "Cannot translate zero through CPM muram
> node");
> > + pr_err("Cannot translate zero through CPM muram node");
> > ret = -ENODEV;
> > - goto out;
> > + goto err;
> > }
> >
> > while (of_address_to_resource(np, i++, &r) == 0) {
> > if (r.end > max)
> > max = r.end;
> > + ret = gen_pool_add(muram_pool, r.start - muram_pbase +
> > + GENPOOL_OFFSET, resource_size(&r), -1);
> > + if (ret) {
> > + pr_err("QE: couldn't add muram to pool!\n");
> > + goto err;
> > + }
> >
> > - rh_attach_region(&cpm_muram_info, r.start - muram_pbase,
> > - resource_size(&r));
> > }
> >
> > muram_vbase = ioremap(muram_pbase, max - muram_pbase + 1);
> > if (!muram_vbase) {
> > - printk(KERN_ERR "Cannot map CPM muram");
> > + pr_err("Cannot map QE muram");
> > ret = -ENOMEM;
> > + goto err;
> > }
> > -
> > + goto out;
> > +err:
> > + gen_pool_destroy(muram_pool);
> > out:
> > of_node_put(np);
> > return ret;
>
> Having both "err" and "out" is confusing. Instead call it "out_pool" or
> similar.

Ok

> > {
> > - int ret;
> > +
> > + unsigned long start;
> > unsigned long flags;
> > + unsigned long size_alloc = size;
> > + struct muram_block *entry;
> > + int end_bit;
> > + int order = muram_pool->min_alloc_order;
> >
> > spin_lock_irqsave(&cpm_muram_lock, flags);
> > - ret = rh_free(&cpm_muram_info, offset);
> > + end_bit = (offset >> order) + ((size + (1UL << order) - 1) >>
> order);
> > + if ((offset + size) > (end_bit << order))
> > + size_alloc = size + (1UL << order);
>
> Why do you need to do all these calculations here?

So do it in gen_pool_fixed_alloc? gen_pool_fixed_alloc just
Can see numbers of blocks. It can't do calculations in gen_pool_fixed_alloc.

>
> > + muram_pool_data_fixed.offset = offset + GENPOOL_OFFSET;
> > + gen_pool_set_algo(muram_pool, gen_pool_fixed_alloc,
> > + &muram_pool_data_fixed);
> > + start = gen_pool_alloc(muram_pool, size_alloc);
> > + if (!start)
> > + goto out2;
> > + start = start - GENPOOL_OFFSET;
> > + memset(cpm_muram_addr(start), 0, size_alloc);
> > + entry = kmalloc(sizeof(*entry), GFP_KERNEL);
> > + if (!entry)
> > + goto out1;
> > + entry->start = start;
> > + entry->size = size_alloc;
> > + list_add(&entry->head, &muram_block_list);
> > spin_unlock_irqrestore(&cpm_muram_lock, flags);
>
> Please factor out the common alloc code.

The common code is as below, what's the function name of this common code, cpm_muram_alloc_common?
gen_pool_set_algo(muram_pool, gen_pool_fixed_alloc,
&muram_pool_data_fixed);
start = gen_pool_alloc(muram_pool, size_alloc);
if (!start)
goto out2;
start = start - GENPOOL_OFFSET;
memset(cpm_muram_addr(start), 0, size_alloc);
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
goto out1;
entry->start = start;
entry->size = size_alloc;
list_add(&entry->head, &muram_block_list);
spin_unlock_irqrestore(&cpm_muram_lock, flags);

return start;
out1:
gen_pool_free(muram_pool, start, size_alloc);
out2:
spin_unlock_irqrestore(&cpm_muram_lock, flags);
return (unsigned long) -ENOMEM;

-Zhao