Re: [PATCH v2 04/18] fpga: dfl: fme: support 512bit data width PR

From: Wu Hao
Date: Fri May 17 2019 - 00:09:11 EST


On Thu, May 16, 2019 at 12:35:27PM -0500, Alan Tull wrote:
> On Mon, Apr 29, 2019 at 4:12 AM Wu Hao <hao.wu@xxxxxxxxx> wrote:
>
> It looks like this addressed the review comments. Adding my Ack. Is
> there anything else on this patch?

Nothing else, just addressed the review comments. : )

Thanks for the review and ack.

Hao

>
> Alan
>
> >
> > In early partial reconfiguration private feature, it only
> > supports 32bit data width when writing data to hardware for
> > PR. 512bit data width PR support is an important optimization
> > for some specific solutions (e.g. XEON with FPGA integrated),
> > it allows driver to use AVX512 instruction to improve the
> > performance of partial reconfiguration. e.g. programming one
> > 100MB bitstream image via this 512bit data width PR hardware
> > only takes ~300ms, but 32bit revision requires ~3s per test
> > result.
> >
> > Please note now this optimization is only done on revision 2
> > of this PR private feature which is only used in integrated
> > solution that AVX512 is always supported. This revision 2
> > hardware doesn't support 32bit PR.
> >
> > Signed-off-by: Ananda Ravuri <ananda.ravuri@xxxxxxxxx>
> > Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
> > Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
>
> Acked-by: Alan Tull <atull@xxxxxxxxxx>
>
>
> > ---
> > v2: check AVX512 support using cpu_feature_enabled()
> > fix other comments from Scott Wood <swood@xxxxxxxxxx>
> > ---
> > drivers/fpga/dfl-fme-main.c | 3 ++
> > drivers/fpga/dfl-fme-mgr.c | 113 +++++++++++++++++++++++++++++++++++++-------
> > drivers/fpga/dfl-fme-pr.c | 43 +++++++++++------
> > drivers/fpga/dfl-fme.h | 2 +
> > drivers/fpga/dfl.h | 5 ++
> > 5 files changed, 135 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
> > index 086ad24..076d74f 100644
> > --- a/drivers/fpga/dfl-fme-main.c
> > +++ b/drivers/fpga/dfl-fme-main.c
> > @@ -21,6 +21,8 @@
> > #include "dfl.h"
> > #include "dfl-fme.h"
> >
> > +#define DRV_VERSION "0.8"
> > +
> > static ssize_t ports_num_show(struct device *dev,
> > struct device_attribute *attr, char *buf)
> > {
> > @@ -277,3 +279,4 @@ static int fme_remove(struct platform_device *pdev)
> > MODULE_AUTHOR("Intel Corporation");
> > MODULE_LICENSE("GPL v2");
> > MODULE_ALIAS("platform:dfl-fme");
> > +MODULE_VERSION(DRV_VERSION);
> > diff --git a/drivers/fpga/dfl-fme-mgr.c b/drivers/fpga/dfl-fme-mgr.c
> > index b3f7eee..d1a4ba5 100644
> > --- a/drivers/fpga/dfl-fme-mgr.c
> > +++ b/drivers/fpga/dfl-fme-mgr.c
> > @@ -22,14 +22,18 @@
> > #include <linux/io-64-nonatomic-lo-hi.h>
> > #include <linux/fpga/fpga-mgr.h>
> >
> > +#include "dfl.h"
> > #include "dfl-fme-pr.h"
> >
> > +#define DRV_VERSION "0.8"
> > +
> > /* FME Partial Reconfiguration Sub Feature Register Set */
> > #define FME_PR_DFH 0x0
> > #define FME_PR_CTRL 0x8
> > #define FME_PR_STS 0x10
> > #define FME_PR_DATA 0x18
> > #define FME_PR_ERR 0x20
> > +#define FME_PR_512_DATA 0x40 /* Data Register for 512bit datawidth PR */
> > #define FME_PR_INTFC_ID_L 0xA8
> > #define FME_PR_INTFC_ID_H 0xB0
> >
> > @@ -67,8 +71,43 @@
> > #define PR_WAIT_TIMEOUT 8000000
> > #define PR_HOST_STATUS_IDLE 0
> >
> > +#if defined(CONFIG_X86) && defined(CONFIG_AS_AVX512)
> > +
> > +#include <linux/cpufeature.h>
> > +#include <asm/fpu/api.h>
> > +
> > +static inline int is_cpu_avx512_enabled(void)
> > +{
> > + return cpu_feature_enabled(X86_FEATURE_AVX512F);
> > +}
> > +
> > +static inline void copy512(const void *src, void __iomem *dst)
> > +{
> > + kernel_fpu_begin();
> > +
> > + asm volatile("vmovdqu64 (%0), %%zmm0;"
> > + "vmovntdq %%zmm0, (%1);"
> > + :
> > + : "r"(src), "r"(dst)
> > + : "memory");
> > +
> > + kernel_fpu_end();
> > +}
> > +#else
> > +static inline int is_cpu_avx512_enabled(void)
> > +{
> > + return 0;
> > +}
> > +
> > +static inline void copy512(const void *src, void __iomem *dst)
> > +{
> > + WARN_ON_ONCE(1);
> > +}
> > +#endif
> > +
> > struct fme_mgr_priv {
> > void __iomem *ioaddr;
> > + unsigned int pr_datawidth;
> > u64 pr_error;
> > };
> >
> > @@ -169,7 +208,7 @@ static int fme_mgr_write(struct fpga_manager *mgr,
> > struct fme_mgr_priv *priv = mgr->priv;
> > void __iomem *fme_pr = priv->ioaddr;
> > u64 pr_ctrl, pr_status, pr_data;
> > - int delay = 0, pr_credit, i = 0;
> > + int ret = 0, delay = 0, pr_credit;
> >
> > dev_dbg(dev, "start request\n");
> >
> > @@ -181,9 +220,9 @@ static int fme_mgr_write(struct fpga_manager *mgr,
> >
> > /*
> > * driver can push data to PR hardware using PR_DATA register once HW
> > - * has enough pr_credit (> 1), pr_credit reduces one for every 32bit
> > - * pr data write to PR_DATA register. If pr_credit <= 1, driver needs
> > - * to wait for enough pr_credit from hardware by polling.
> > + * has enough pr_credit (> 1), pr_credit reduces one for every pr data
> > + * width write to PR_DATA register. If pr_credit <= 1, driver needs to
> > + * wait for enough pr_credit from hardware by polling.
> > */
> > pr_status = readq(fme_pr + FME_PR_STS);
> > pr_credit = FIELD_GET(FME_PR_STS_PR_CREDIT, pr_status);
> > @@ -192,7 +231,8 @@ static int fme_mgr_write(struct fpga_manager *mgr,
> > while (pr_credit <= 1) {
> > if (delay++ > PR_WAIT_TIMEOUT) {
> > dev_err(dev, "PR_CREDIT timeout\n");
> > - return -ETIMEDOUT;
> > + ret = -ETIMEDOUT;
> > + goto done;
> > }
> > udelay(1);
> >
> > @@ -200,21 +240,27 @@ static int fme_mgr_write(struct fpga_manager *mgr,
> > pr_credit = FIELD_GET(FME_PR_STS_PR_CREDIT, pr_status);
> > }
> >
> > - if (count < 4) {
> > - dev_err(dev, "Invalid PR bitstream size\n");
> > - return -EINVAL;
> > + WARN_ON(count < priv->pr_datawidth);
> > +
> > + switch (priv->pr_datawidth) {
> > + case 4:
> > + pr_data = FIELD_PREP(FME_PR_DATA_PR_DATA_RAW,
> > + *(u32 *)buf);
> > + writeq(pr_data, fme_pr + FME_PR_DATA);
> > + break;
> > + case 64:
> > + copy512(buf, fme_pr + FME_PR_512_DATA);
> > + break;
> > + default:
> > + WARN_ON_ONCE(1);
> > }
> > -
> > - pr_data = 0;
> > - pr_data |= FIELD_PREP(FME_PR_DATA_PR_DATA_RAW,
> > - *(((u32 *)buf) + i));
> > - writeq(pr_data, fme_pr + FME_PR_DATA);
> > - count -= 4;
> > + buf += priv->pr_datawidth;
> > + count -= priv->pr_datawidth;
> > pr_credit--;
> > - i++;
> > }
> >
> > - return 0;
> > +done:
> > + return ret;
> > }
> >
> > static int fme_mgr_write_complete(struct fpga_manager *mgr,
> > @@ -279,6 +325,36 @@ static void fme_mgr_get_compat_id(void __iomem *fme_pr,
> > id->id_h = readq(fme_pr + FME_PR_INTFC_ID_H);
> > }
> >
> > +static u8 fme_mgr_get_pr_datawidth(struct device *dev, void __iomem *fme_pr)
> > +{
> > + u8 revision = dfl_feature_revision(fme_pr);
> > +
> > + if (revision < 2) {
> > + /*
> > + * revision 0 and 1 only support 32bit data width partial
> > + * reconfiguration, so pr_datawidth is 4 (Byte).
> > + */
> > + return 4;
> > + } else if (revision == 2) {
> > + /*
> > + * revision 2 hardware has optimization to support 512bit data
> > + * width partial reconfiguration with AVX512 instructions. So
> > + * pr_datawidth is 64 (Byte). As revision 2 hardware is only
> > + * used in integrated solution, CPU supports AVX512 instructions
> > + * for sure, but it still needs to check here as AVX512 could be
> > + * disabled in kernel (e.g. using clearcpuid boot option).
> > + */
> > + if (is_cpu_avx512_enabled())
> > + return 64;
> > +
> > + dev_err(dev, "revision 2: AVX512 is disabled\n");
> > + return 0;
> > + }
> > +
> > + dev_err(dev, "revision %d is not supported yet\n", revision);
> > + return 0;
> > +}
> > +
> > static int fme_mgr_probe(struct platform_device *pdev)
> > {
> > struct dfl_fme_mgr_pdata *pdata = dev_get_platdata(&pdev->dev);
> > @@ -302,6 +378,10 @@ static int fme_mgr_probe(struct platform_device *pdev)
> > return PTR_ERR(priv->ioaddr);
> > }
> >
> > + priv->pr_datawidth = fme_mgr_get_pr_datawidth(dev, priv->ioaddr);
> > + if (!priv->pr_datawidth)
> > + return -ENODEV;
> > +
> > compat_id = devm_kzalloc(dev, sizeof(*compat_id), GFP_KERNEL);
> > if (!compat_id)
> > return -ENOMEM;
> > @@ -342,3 +422,4 @@ static int fme_mgr_remove(struct platform_device *pdev)
> > MODULE_AUTHOR("Intel Corporation");
> > MODULE_LICENSE("GPL v2");
> > MODULE_ALIAS("platform:dfl-fme-mgr");
> > +MODULE_VERSION(DRV_VERSION);
> > diff --git a/drivers/fpga/dfl-fme-pr.c b/drivers/fpga/dfl-fme-pr.c
> > index 3c71dc3..cd94ba8 100644
> > --- a/drivers/fpga/dfl-fme-pr.c
> > +++ b/drivers/fpga/dfl-fme-pr.c
> > @@ -83,7 +83,7 @@ static int fme_pr(struct platform_device *pdev, unsigned long arg)
> > if (copy_from_user(&port_pr, argp, minsz))
> > return -EFAULT;
> >
> > - if (port_pr.argsz < minsz || port_pr.flags)
> > + if (port_pr.argsz < minsz || port_pr.flags || !port_pr.buffer_size)
> > return -EINVAL;
> >
> > /* get fme header region */
> > @@ -101,15 +101,25 @@ static int fme_pr(struct platform_device *pdev, unsigned long arg)
> > port_pr.buffer_size))
> > return -EFAULT;
> >
> > + mutex_lock(&pdata->lock);
> > + fme = dfl_fpga_pdata_get_private(pdata);
> > + /* fme device has been unregistered. */
> > + if (!fme) {
> > + ret = -EINVAL;
> > + goto unlock_exit;
> > + }
> > +
> > /*
> > * align PR buffer per PR bandwidth, as HW ignores the extra padding
> > * data automatically.
> > */
> > - length = ALIGN(port_pr.buffer_size, 4);
> > + length = ALIGN(port_pr.buffer_size, fme->pr_datawidth);
> >
> > buf = vmalloc(length);
> > - if (!buf)
> > - return -ENOMEM;
> > + if (!buf) {
> > + ret = -ENOMEM;
> > + goto unlock_exit;
> > + }
> >
> > if (copy_from_user(buf,
> > (void __user *)(unsigned long)port_pr.buffer_address,
> > @@ -127,18 +137,10 @@ static int fme_pr(struct platform_device *pdev, unsigned long arg)
> >
> > info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
> >
> > - mutex_lock(&pdata->lock);
> > - fme = dfl_fpga_pdata_get_private(pdata);
> > - /* fme device has been unregistered. */
> > - if (!fme) {
> > - ret = -EINVAL;
> > - goto unlock_exit;
> > - }
> > -
> > region = dfl_fme_region_find(fme, port_pr.port_id);
> > if (!region) {
> > ret = -EINVAL;
> > - goto unlock_exit;
> > + goto free_exit;
> > }
> >
> > fpga_image_info_free(region->info);
> > @@ -159,10 +161,10 @@ static int fme_pr(struct platform_device *pdev, unsigned long arg)
> > fpga_bridges_put(&region->bridge_list);
> >
> > put_device(&region->dev);
> > -unlock_exit:
> > - mutex_unlock(&pdata->lock);
> > free_exit:
> > vfree(buf);
> > +unlock_exit:
> > + mutex_unlock(&pdata->lock);
> > return ret;
> > }
> >
> > @@ -388,6 +390,17 @@ static int pr_mgmt_init(struct platform_device *pdev,
> > mutex_lock(&pdata->lock);
> > priv = dfl_fpga_pdata_get_private(pdata);
> >
> > + /*
> > + * Initialize PR data width.
> > + * Only revision 2 supports 512bit datawidth for better performance,
> > + * other revisions use default 32bit datawidth. This is used for
> > + * buffer alignment.
> > + */
> > + if (dfl_feature_revision(feature->ioaddr) == 2)
> > + priv->pr_datawidth = 64;
> > + else
> > + priv->pr_datawidth = 4;
> > +
> > /* Initialize the region and bridge sub device list */
> > INIT_LIST_HEAD(&priv->region_list);
> > INIT_LIST_HEAD(&priv->bridge_list);
> > diff --git a/drivers/fpga/dfl-fme.h b/drivers/fpga/dfl-fme.h
> > index 5394a21..de20755 100644
> > --- a/drivers/fpga/dfl-fme.h
> > +++ b/drivers/fpga/dfl-fme.h
> > @@ -21,12 +21,14 @@
> > /**
> > * struct dfl_fme - dfl fme private data
> > *
> > + * @pr_datawidth: data width for partial reconfiguration.
> > * @mgr: FME's FPGA manager platform device.
> > * @region_list: linked list of FME's FPGA regions.
> > * @bridge_list: linked list of FME's FPGA bridges.
> > * @pdata: fme platform device's pdata.
> > */
> > struct dfl_fme {
> > + int pr_datawidth;
> > struct platform_device *mgr;
> > struct list_head region_list;
> > struct list_head bridge_list;
> > diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> > index a8b869e..8851c6c 100644
> > --- a/drivers/fpga/dfl.h
> > +++ b/drivers/fpga/dfl.h
> > @@ -331,6 +331,11 @@ static inline bool dfl_feature_is_port(void __iomem *base)
> > (FIELD_GET(DFH_ID, v) == DFH_ID_FIU_PORT);
> > }
> >
> > +static inline u8 dfl_feature_revision(void __iomem *base)
> > +{
> > + return (u8)FIELD_GET(DFH_REVISION, readq(base + DFH));
> > +}
> > +
> > /**
> > * struct dfl_fpga_enum_info - DFL FPGA enumeration information
> > *
> > --
> > 1.8.3.1
> >