| Message ID | 1401250073-16603-1-git-send-email-akong@redhat.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
Hi Amos, On Wed, May 28, 2014 at 6:07 AM, Amos Kong <akong@redhat.com> wrote: > 16K is 2^2 * PAGE_SIZE, so the page order should be 2, not 3. > > This patch uses get_order() to get correct order, and fixes > one typo in comment. Thanks for your patch! > Signed-off-by: Amos Kong <akong@redhat.com> > --- > This patch wasn't built. Geert, can you help to test it? > I don't know if it needs a head file by using get_order(). It builds fine. The get_order() is nicely expanded to "2" in the assembler output. Now, I'd like to get some feedback from the MVME hackers first. Perhaps the comment was wrong? > -/* We have 16834 bytes of RAM for the init block and buffers. This places > +/* We have 16384 bytes of RAM for the init block and buffers. This places > * an upper limit on the number of buffers we can use. NetBSD uses 8 Rx > * buffers and 2 Tx buffers. > */ > +#define M147LANCE_RAM_SIZE 16384 /* 16K */ > #define LANCE_LOG_TX_BUFFERS 1 > #define LANCE_LOG_RX_BUFFERS 3 BTW,I also find it fishy why the driver uses only 1+3 buffers, since more RAM is available. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Geert Uytterhoeven <geert@linux-m68k.org> writes: >> -/* We have 16834 bytes of RAM for the init block and buffers. This places >> +/* We have 16384 bytes of RAM for the init block and buffers. This places >> * an upper limit on the number of buffers we can use. NetBSD uses 8 Rx >> * buffers and 2 Tx buffers. >> */ >> +#define M147LANCE_RAM_SIZE 16384 /* 16K */ >> #define LANCE_LOG_TX_BUFFERS 1 >> #define LANCE_LOG_RX_BUFFERS 3 > > BTW,I also find it fishy why the driver uses only 1+3 buffers, since more > RAM is available. It's 2^1+2^3. Andreas.
On Wed, May 28, 2014 at 11:39:20AM +0200, Andreas Schwab wrote: > Geert Uytterhoeven <geert@linux-m68k.org> writes: > > >> -/* We have 16834 bytes of RAM for the init block and buffers. This places > >> +/* We have 16384 bytes of RAM for the init block and buffers. This places > >> * an upper limit on the number of buffers we can use. NetBSD uses 8 Rx > >> * buffers and 2 Tx buffers. > >> */ > >> +#define M147LANCE_RAM_SIZE 16384 /* 16K */ > >> #define LANCE_LOG_TX_BUFFERS 1 > >> #define LANCE_LOG_RX_BUFFERS 3 > > #define TX_RING_SIZE (1 << LANCE_LOG_TX_BUFFERS) #define RX_RING_SIZE (1 << LANCE_LOG_RX_BUFFERS) > > BTW,I also find it fishy why the driver uses only 1+3 buffers, since more > > RAM is available. > > It's 2^1+2^3. tx & rx bufs aren't 2^1 + 2^3 = 10 pages. Rx buffers and Tx buffers are included in 'struct lance_init_block' volatile char tx_buf[TX_RING_SIZE][TX_BUFF_SIZE]; volatile char rx_buf[RX_RING_SIZE][RX_BUFF_SIZE]; volatile char tx_buf[2][1544]; volatile char rx_buf[8][1544]; RX_BUFF_SIZE = TX_BUFF_SIZE = 1554 So tx_buf takes 1544 * 2 bytes, rx_buf takes 1544 * 8 bytes In drivers/net/ethernet/amd/mvme147.c: ===================================== lp->lance.init_block = (struct lance_init_block *)(lp->ram); /* CPU addr */ lp->lance.lance_init_block = (struct lance_init_block*)(lp->ram); /* LANCE addr of same RAM */ init_block and lance_init_block are set same address In drivers/net/ethernet/amd/a2065.c: =================================== priv->init_block = (struct lance_init_block *)dev->mem_start; priv->lance_init_block = (struct lance_init_block *)A2065_RAM; The ram size (A2065_RAM_SIZE) is 0x8000 -> 8 pages -> order is 3 It seems original 3 is a right order, we need to fix the comments. it's 2^3 * 4k = 32K = 32768 bytes. But in drivers/net/ethernet/amd/hplance.c: ========================================= #define HPLANCE_MEMOFF 0x8000 /* struct lance_init_block */ lp->lance.init_block = (struct lance_init_block *)(va + HPLANCE_MEMOFF); /* CPU addr */ ^^^^ it skips 0x8000, that is for HPLANCE lp->lance.lance_init_block = NULL; /* LANCE addr of same RAM */ We need 2 * 32k for lp->ram? > Andreas. > > -- > Andreas Schwab, schwab@linux-m68k.org > GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 > "And now for something completely different." > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/amd/mvme147.c b/drivers/net/ethernet/amd/mvme147.c index 0e8399d..4e98bf8 100644 --- a/drivers/net/ethernet/amd/mvme147.c +++ b/drivers/net/ethernet/amd/mvme147.c @@ -26,10 +26,11 @@ #include <asm/pgtable.h> #include <asm/mvme147hw.h> -/* We have 16834 bytes of RAM for the init block and buffers. This places +/* We have 16384 bytes of RAM for the init block and buffers. This places * an upper limit on the number of buffers we can use. NetBSD uses 8 Rx * buffers and 2 Tx buffers. */ +#define M147LANCE_RAM_SIZE 16384 /* 16K */ #define LANCE_LOG_TX_BUFFERS 1 #define LANCE_LOG_RX_BUFFERS 3 @@ -111,7 +112,7 @@ struct net_device * __init mvme147lance_probe(int unit) dev->dev_addr); lp = netdev_priv(dev); - lp->ram = __get_dma_pages(GFP_ATOMIC, 3); /* 16K */ + lp->ram = __get_dma_pages(GFP_ATOMIC, get_order(M147LANCE_RAM_SIZE)); if (!lp->ram) { printk("%s: No memory for LANCE buffers\n", dev->name); free_netdev(dev); @@ -134,7 +135,7 @@ struct net_device * __init mvme147lance_probe(int unit) err = register_netdev(dev); if (err) { - free_pages(lp->ram, 3); + free_pages(lp->ram, get_order(M147LANCE_RAM_SIZE)); free_netdev(dev); return ERR_PTR(err); } @@ -193,7 +194,7 @@ void __exit cleanup_module(void) { struct m147lance_private *lp = netdev_priv(dev_mvme147_lance); unregister_netdev(dev_mvme147_lance); - free_pages(lp->ram, 3); + free_pages(lp->ram, get_order(M147LANCE_RAM_SIZE)); free_netdev(dev_mvme147_lance); }
16K is 2^2 * PAGE_SIZE, so the page order should be 2, not 3. This patch uses get_order() to get correct order, and fixes one typo in comment. Signed-off-by: Amos Kong <akong@redhat.com> --- This patch wasn't built. Geert, can you help to test it? I don't know if it needs a head file by using get_order(). --- drivers/net/ethernet/amd/mvme147.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)