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Date: Mon, 15 Oct 2018 17:17:40 +1100 (AEDT)
From: Finn Thain <fthain@...egraphics.com.au>
To: Hannes Reinecke <hare@...e.de>
cc: "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Michael Schmitz <schmitzmic@...il.com>,
linux-scsi@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] esp_scsi: De-duplicate PIO routines
On Mon, 15 Oct 2018, Hannes Reinecke wrote:
> On 10/13/18 2:51 AM, Finn Thain wrote:
> > As a temporary measure, the code to implement PIO transfers was
> > duplicated in zorro_esp and mac_esp. Now that this code has stabilized,
> > move it into the core driver to eliminate the duplication.
> >
> > This replaces the inline assembler with more portable writesb() calls.
> > Optimizing the m68k writesb() implementation is a separate patch.
> >
> > Tested-by: Stan Johnson <userm57@...oo.com>
> > Signed-off-by: Finn Thain <fthain@...egraphics.com.au>
> > ---
> > drivers/scsi/esp_scsi.c | 126 +++++++++++++++++++++++++
> > drivers/scsi/esp_scsi.h | 5 +
> > drivers/scsi/mac_esp.c | 173 ++---------------------------------
> > drivers/scsi/zorro_esp.c | 232 +++++++----------------------------------------
> > 4 files changed, 171 insertions(+), 365 deletions(-)
> >
> > diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
> > index 6ccaf818357e..646701fc22a4 100644
> > --- a/drivers/scsi/esp_scsi.c
> > +++ b/drivers/scsi/esp_scsi.c
> > @@ -2776,3 +2776,129 @@ MODULE_PARM_DESC(esp_debug,
> >
> > module_init(esp_init);
> > module_exit(esp_exit);
> > +
> > +#if IS_ENABLED(CONFIG_SCSI_MAC_ESP) || IS_ENABLED(CONFIG_SCSI_ZORRO_ESP)
> > +static inline unsigned int esp_wait_for_fifo(struct esp *esp)
> > +{
> > + int i = 500000;
> > +
> > + do {
> > + unsigned int fbytes = esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES;
> > +
> > + if (fbytes)
> > + return fbytes;
> > +
> > + udelay(2);
> > + } while (--i);
> > +
> > + pr_err("FIFO is empty (sreg %02x)\n", esp_read8(ESP_STATUS));
> > + return 0;
> > +}
> > +
> > +static inline int esp_wait_for_intr(struct esp *esp)
> > +{
> > + int i = 500000;
> > +
> > + do {
> > + esp->sreg = esp_read8(ESP_STATUS);
> > + if (esp->sreg & ESP_STAT_INTR)
> > + return 0;
> > +
> > + udelay(2);
> > + } while (--i);
> > +
> > + pr_err("IRQ timeout (sreg %02x)\n", esp->sreg);
> > + return 1;
> > +}
> > +
> > +#define ESP_FIFO_SIZE 16
> > +
> > +void esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
> > + u32 dma_count, int write, u8 cmd)
> > +{
> > + u8 phase = esp->sreg & ESP_STAT_PMASK;
> > +
> > + cmd &= ~ESP_CMD_DMA;
> > + esp->send_cmd_error = 0;
> > +
> > + if (write) {
> > + u8 *dst = (u8 *)addr;
> > + u8 mask = ~(phase == ESP_MIP ? ESP_INTR_FDONE : ESP_INTR_BSERV);
> > +
> > + scsi_esp_cmd(esp, cmd);
> > +
> > + while (1) {
> > + if (!esp_wait_for_fifo(esp))
> > + break;
> > +
> > + *dst++ = esp_read8(ESP_FDATA);
> > + --esp_count;
> > +
> > + if (!esp_count)
> > + break;
> > +
> > + if (esp_wait_for_intr(esp)) {
> > + esp->send_cmd_error = 1;
> > + break;
> > + }
> > +
> > + if ((esp->sreg & ESP_STAT_PMASK) != phase)
> > + break;
> > +
> > + esp->ireg = esp_read8(ESP_INTRPT);
> > + if (esp->ireg & mask) {
> > + esp->send_cmd_error = 1;
> > + break;
> > + }
> > +
> > + if (phase == ESP_MIP)
> > + scsi_esp_cmd(esp, ESP_CMD_MOK);
> > +
> > + scsi_esp_cmd(esp, ESP_CMD_TI);
> > + }
> > + } else {
> > + unsigned int n = ESP_FIFO_SIZE;
> > + u8 *src = (u8 *)addr;
> > +
> > + scsi_esp_cmd(esp, ESP_CMD_FLUSH);
> > +
> > + if (n > esp_count)
> > + n = esp_count;
> > + writesb(esp->fifo_reg, src, n);
> > + src += n;
> > + esp_count -= n;
> > +
> > + scsi_esp_cmd(esp, cmd);
> > +
> > + while (esp_count) {
> > + if (esp_wait_for_intr(esp)) {
> > + esp->send_cmd_error = 1;
> > + break;
> > + }
> > +
> > + if ((esp->sreg & ESP_STAT_PMASK) != phase)
> > + break;
> > +
> > + esp->ireg = esp_read8(ESP_INTRPT);
> > + if (esp->ireg & ~ESP_INTR_BSERV) {
> > + esp->send_cmd_error = 1;
> > + break;
> > + }
> > +
> > + n = ESP_FIFO_SIZE -
> > + (esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES);
> > +
> > + if (n > esp_count)
> > + n = esp_count;
> > + writesb(esp->fifo_reg, src, n);
> > + src += n;
> > + esp_count -= n;
> > +
> > + scsi_esp_cmd(esp, ESP_CMD_TI);
> > + }
> > + }
> > +
> > + esp->send_cmd_residual = esp_count;
> > +}
> > +EXPORT_SYMBOL(esp_send_pio_cmd);
> > +#endif
>
> These function are conditional, but
>
> > diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
> > index d0c032803749..2590e5eda595 100644
> > --- a/drivers/scsi/esp_scsi.h
> > +++ b/drivers/scsi/esp_scsi.h
> > @@ -431,6 +431,7 @@ struct esp_driver_ops {
> > struct esp {
> > void __iomem *regs;
> > void __iomem *dma_regs;
> > + u8 __iomem *fifo_reg;
> >
> > const struct esp_driver_ops *ops;
> >
> > @@ -540,6 +541,7 @@ struct esp {
> > void *dma;
> > int dmarev;
> >
> > + int send_cmd_error;
> > int send_cmd_residual;
> > };
> >
> > @@ -581,4 +583,7 @@ extern void scsi_esp_unregister(struct esp *);
> > extern irqreturn_t scsi_esp_intr(int, void *);
> > extern void scsi_esp_cmd(struct esp *, u8);
> >
> > +extern void esp_send_pio_cmd(struct esp *esp, u32 dma_addr, u32 esp_count,
> > + u32 dma_count, int write, u8 cmd);
> > +
> > #endif /* !(_ESP_SCSI_H) */
> These are not.
>
> Which will result in building errors when the said configuration is not
> enabled.
I didn't see errors or new warnings when build-testing with
CONFIG_SCSI_AM53C974=y with gcc-5.4 or gcc-7.3, nor when build-testing
CONFIG_SUN3X_ESP=y with gcc-4.4.
Are you perhaps thinking of "declared static but never defined"? That
doesn't apply here because esp_send_pio_cmd() isn't static. Likewise
"static declaration of 'foo' follows non-static declaration"...
--
> Cheers,
>
> Hannes
> --
> Dr. Hannes Reinecke Teamlead Storage & Networking
> hare@...e.de +49 911 74053 688
> SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N?rnberg
> GF: F. Imend?rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
> HRB 21284 (AG N?rnberg)
>
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