From: David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
To: Bryan Wu <cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
Yi Li <yi.li-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 15/16] Blackfin SPI Driver: fix bug - spi controller driver does not assert/deassert CS correctly
Date: Thu, 20 Nov 2008 12:47:46 -0800 [thread overview]
Message-ID: <200811201247.46730.david-b@pacbell.net> (raw)
In-Reply-To: <1226994760-4301-16-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
On Monday 17 November 2008, Bryan Wu wrote:
> From: Yi Li <yi.li-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
>
> This bug can be observed when two SPI devices are sharing the spi bus:
> One device is set as SPI CS 7, another one is using SPI CS 4.
>
> In spi_bfin5xx.c: cs_active(), cs_deactive() are used to control SPI_FLG
> register. From the debug bellow:
>
> cs_active: flag: 0x7f91, chip->flag: 0x7f80, cs: 7
> cs_active: flag: 0xef91, chip->flag: 0xef10, cs: 4
>
> When device A (cs_7) activate CS 7, SPI_FLG is set as 0x7f91 (however,
> SPI_FLG should be set as 0x7f80, or 0x6f91 if in broadcast mode).
>
> Due to some HW bug (very possibly), if SPI_FLG is set as 0x7f91,
> SPISSEL7 is asserted, however SPISSEL4 will be asserted too (I can see
> this using the scope). This is unreasonable according to HRM.
>
> Signed-off-by: Yi Li <yi.li-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Bryan Wu <cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Acked-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Yay! Real patch comments! Although ... it doesn't exactly
say *how* it was fixed, which would make the comments better.
("Clear flags that were wrongly left set." maybe.)
Saying what was fixed is at least a start.
> ---
> drivers/spi/spi_bfin5xx.c | 5 ++---
> 1 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
> index 9c602ad..8cf5d6e 100644
> --- a/drivers/spi/spi_bfin5xx.c
> +++ b/drivers/spi/spi_bfin5xx.c
> @@ -189,6 +189,7 @@ static void cs_deactive(struct driver_data *drv_data, struct chip_data *chip)
> {
> u16 flag = read_FLAG(drv_data);
>
> + flag &= ~chip->flag;
> flag |= (chip->flag << 8);
>
> write_FLAG(drv_data, flag);
> @@ -1032,7 +1033,6 @@ static int setup(struct spi_device *spi)
> struct bfin5xx_spi_chip *chip_info = NULL;
> struct chip_data *chip;
> struct driver_data *drv_data = spi_master_get_devdata(spi->master);
> - u8 spi_flg;
>
> /* Abort device setup if requested features are not supported */
> if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST)) {
> @@ -1115,8 +1115,7 @@ static int setup(struct spi_device *spi)
> * SPI_BAUD, not the real baudrate
> */
> chip->baud = hz_to_spi_baud(spi->max_speed_hz);
> - spi_flg = ~(1 << (spi->chip_select));
> - chip->flag = ((u16) spi_flg << 8) | (1 << (spi->chip_select));
> + chip->flag = 1 << (spi->chip_select);
> chip->chip_select_num = spi->chip_select;
>
> switch (chip->bits_per_word) {
> --
> 1.5.6.3
>
>
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next prev parent reply other threads:[~2008-11-20 20:47 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-18 7:52 (no subject) Bryan Wu
[not found] ` <1226994760-4301-1-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-18 7:52 ` [PATCH 01/16] Blackfin SPI Driver: ensure cache coherency before doing DMA Bryan Wu
[not found] ` <1226994760-4301-2-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:24 ` David Brownell
[not found] ` <200811201224.15493.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-11-20 20:58 ` Mike Frysinger
[not found] ` <8bd0f97a0811201258j14dfcf46vce1655632bb12e2-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-11-20 21:47 ` David Brownell
[not found] ` <200811201347.46355.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-11-20 21:57 ` Mike Frysinger
[not found] ` <8bd0f97a0811201357g1ffeb7d3pfad6e178fb20050e-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-11-20 22:05 ` David Brownell
[not found] ` <200811201405.06811.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2009-02-05 9:30 ` Bryan Wu
2009-02-05 23:51 ` David Brownell
[not found] ` <200902051551.14146.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2009-02-06 2:31 ` Bryan Wu
2008-11-18 7:52 ` [PATCH 02/16] Blackfin SPI Driver: Fix erroneous SPI Clock divisor calculation Bryan Wu
[not found] ` <1226994760-4301-3-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:25 ` David Brownell
2008-11-18 7:52 ` [PATCH 03/16] Blackfin SPI Driver: move bfin_addr_dcachable() and friends into the cacheflush header where it belongs Bryan Wu
[not found] ` <1226994760-4301-4-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:26 ` David Brownell
2008-11-18 7:52 ` [PATCH 04/16] Blackfin SPI Driver: use len_in_bytes when we care about the number of bytes transferred Bryan Wu
[not found] ` <1226994760-4301-5-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:25 ` David Brownell
2008-11-18 7:52 ` [PATCH 05/16] Blackfin SPI Driver: pass DMA overflow error to the higher level Bryan Wu
[not found] ` <1226994760-4301-6-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:29 ` David Brownell
2008-11-18 7:52 ` [PATCH 06/16] Blackfin SPI Driver: unify duplicated code in dma read/write paths Bryan Wu
[not found] ` <1226994760-4301-7-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:32 ` David Brownell
2008-11-18 7:52 ` [PATCH 07/16] Blackfin SPI Driver: drop bogus cast and touchup dma label Bryan Wu
[not found] ` <1226994760-4301-8-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:34 ` David Brownell
2008-11-18 7:52 ` [PATCH 08/16] Blackfin SPI Driver: add a few more debug messages in useful places Bryan Wu
[not found] ` <1226994760-4301-9-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:35 ` David Brownell
2008-11-18 7:52 ` [PATCH 09/16] Blackfin SPI Driver: do not check for SPI errors if DMA itself did not flag any Bryan Wu
2008-11-18 7:52 ` [PATCH 10/16] Blackfin SPI Driver: use the properl BIT_CTL_xxx defines Bryan Wu
[not found] ` <1226994760-4301-11-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:37 ` David Brownell
2008-11-18 7:52 ` [PATCH 11/16] Blackfin SPI Driver: remove duplicated MAX_SPI_SSEL and remove unnecessary array size Bryan Wu
2008-11-18 7:52 ` [PATCH 12/16] Blackfin SPI Driver: get dma working for SPI flashes Bryan Wu
[not found] ` <1226994760-4301-13-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:43 ` David Brownell
2008-11-18 7:52 ` [PATCH 13/16] Blackfin SPI Driver: add timeout while waiting for SPIF in dma irq handler Bryan Wu
2008-11-18 7:52 ` [PATCH 14/16] Blackfin SPI Driver: tweak magic spi dma sequence to get it working on BF54x Bryan Wu
2008-11-18 7:52 ` [PATCH 15/16] Blackfin SPI Driver: fix bug - spi controller driver does not assert/deassert CS correctly Bryan Wu
[not found] ` <1226994760-4301-16-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:47 ` David Brownell [this message]
2008-11-18 7:52 ` [PATCH 16/16] Blackfin SPI Driver: fix bug - correct usage of struct spi_transfer.cs_change Bryan Wu
[not found] ` <1226994760-4301-17-git-send-email-cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2008-11-20 20:51 ` David Brownell
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