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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 15 Mar 2018 15:46:06 +0100
Message-ID: <CAK8P3a2PFSJa5UKHrB14zz8siRCpUzkL5hffTM8ku5ep3pUjCw@mail.gmail.com>
Subject: Re: [Blackfin removal] [PATCH 01/28] Blackfin arch: Remove Blackfin
 CPU arch general support
To:     Arnd Bergmann <arnd@arndb.de>,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lennox Wu <lennox.wu@gmail.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Jonas Bonn <jonas@southpole.se>,
        Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
        Stafford Horne <shorne@gmail.com>,
        David Howells <dhowells@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Wu, Aaron" <aaron.wu@analog.com>
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Sender: linux-kernel-owner@vger.kernel.org
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> Signed-off-by: Aaron Wu <aaron.wu@analog.com>
>
> Remove Blackfin CPU arch general support

Hi Aaron,

thanks a lot for your series. As you know, I've had almost the
same patches in my tree already, but now I've cross-checked the
two versions, and found small omissions or bugs in both. I
ended up staying with my version, as that was already reviewed
by a number of people, and it had the conflicts with the other
arch removal resolved, but I've folded in everything that your
version had that I was missing, see below for the diff between
my original version and the new one.

I've also added an 'Acked-by: Aaron Wu <aaron.wu@analog.com>'
to each patch that we both had.

I hope that all works for you.

       Arnd

---
 Documentation/driver-api/usb/writing_musb_glue_layer.rst |    3
 drivers/misc/echo/echo.c                                 |   73 ------------
 drivers/misc/echo/fir.h                                  |   50 --------
 drivers/usb/gadget/function/f_uac1_legacy.c              |    2
 drivers/usb/gadget/function/u_uac1_legacy.c              |    2
 drivers/usb/gadget/function/u_uac1_legacy.h              |    2
 drivers/usb/gadget/legacy/audio.c                        |    2
 drivers/usb/host/isp1362.h                               |    4
 drivers/usb/musb/musb_core.c                             |    2
 drivers/usb/musb/musb_core.h                             |   13 --
 include/linux/cpuhotplug.h                               |    1
 include/linux/fb.h                                       |    3
 14 files changed, 3 insertions(+), 248 deletions(-)

diff --git a/drivers/misc/echo/echo.c b/drivers/misc/echo/echo.c
index 9597e9523cac..8a5adc0d2e88 100644
--- a/drivers/misc/echo/echo.c
+++ b/drivers/misc/echo/echo.c
@@ -115,78 +115,6 @@

 /* adapting coeffs using the traditional stochastic descent (N)LMS algorithm */

-#ifdef __bfin__
-static inline void lms_adapt_bg(struct oslec_state *ec, int clean, int shift)
-{
- int i;
- int offset1;
- int offset2;
- int factor;
- int exp;
- int16_t *phist;
- int n;
-
- if (shift > 0)
- factor = clean << shift;
- else
- factor = clean >> -shift;
-
- /* Update the FIR taps */
-
- offset2 = ec->curr_pos;
- offset1 = ec->taps - offset2;
- phist = &ec->fir_state_bg.history[offset2];
-
- /* st: and en: help us locate the assembler in echo.s */
-
- /* asm("st:"); */
- n = ec->taps;
- for (i = 0; i < n; i++) {
- exp = *phist++ * factor;
- ec->fir_taps16[1][i] += (int16_t) ((exp + (1 << 14)) >> 15);
- }
- /* asm("en:"); */
-
- /* Note the asm for the inner loop above generated by Blackfin gcc
-    4.1.1 is pretty good (note even parallel instructions used):
-
-    R0 = W [P0++] (X);
-    R0 *= R2;
-    R0 = R0 + R3 (NS) ||
-    R1 = W [P1] (X) ||
-    nop;
-    R0 >>>= 15;
-    R0 = R0 + R1;
-    W [P1++] = R0;
-
-    A block based update algorithm would be much faster but the
-    above can't be improved on much.  Every instruction saved in
-    the loop above is 2 MIPs/ch!  The for loop above is where the
-    Blackfin spends most of it's time - about 17 MIPs/ch measured
-    with speedtest.c with 256 taps (32ms).  Write-back and
-    Write-through cache gave about the same performance.
- */
-}
-
-/*
-   IDEAS for further optimisation of lms_adapt_bg():
-
-   1/ The rounding is quite costly.  Could we keep as 32 bit coeffs
-   then make filter pluck the MS 16-bits of the coeffs when filtering?
-   However this would lower potential optimisation of filter, as I
-   think the dual-MAC architecture requires packed 16 bit coeffs.
-
-   2/ Block based update would be more efficient, as per comments above,
-   could use dual MAC architecture.
-
-   3/ Look for same sample Blackfin LMS code, see if we can get dual-MAC
-   packing.
-
-   4/ Execute the whole e/c in a block of say 20ms rather than sample
-   by sample.  Processing a few samples every ms is inefficient.
-*/
-
-#else
 static inline void lms_adapt_bg(struct oslec_state *ec, int clean, int shift)
 {
  int i;
@@ -215,7 +143,6 @@ static inline void lms_adapt_bg(struct oslec_state
*ec, int clean, int shift)
  ec->fir_taps16[1][i] += (int16_t) ((exp + (1 << 14)) >> 15);
  }
 }
-#endif

 static inline int top_bit(unsigned int bits)
 {
diff --git a/drivers/misc/echo/fir.h b/drivers/misc/echo/fir.h
index 7b9fabf1fea5..4e0f365f0577 100644
--- a/drivers/misc/echo/fir.h
+++ b/drivers/misc/echo/fir.h
@@ -27,14 +27,6 @@
 #define _FIR_H_

 /*
-   Blackfin NOTES & IDEAS:
-
-   A simple dot product function is used to implement the filter.
This performs
-   just one MAC/cycle which is inefficient but was easy to implement as a first
-   pass.  The current Blackfin code also uses an unrolled form of the filter
-   history to avoid 0 length hardware loop issues.  This is wasteful of
-   memory.
-
    Ideas for improvement:

    1/ Rewrite filter for dual MAC inner loop.  The issue here is handling
@@ -94,21 +86,13 @@ static inline const int16_t *fir16_create(struct
fir16_state_t *fir,
  fir->taps = taps;
  fir->curr_pos = taps - 1;
  fir->coeffs = coeffs;
-#if defined(__bfin__)
- fir->history = kcalloc(2 * taps, sizeof(int16_t), GFP_KERNEL);
-#else
  fir->history = kcalloc(taps, sizeof(int16_t), GFP_KERNEL);
-#endif
  return fir->history;
 }

 static inline void fir16_flush(struct fir16_state_t *fir)
 {
-#if defined(__bfin__)
- memset(fir->history, 0, 2 * fir->taps * sizeof(int16_t));
-#else
  memset(fir->history, 0, fir->taps * sizeof(int16_t));
-#endif
 }

 static inline void fir16_free(struct fir16_state_t *fir)
@@ -116,42 +100,9 @@ static inline void fir16_free(struct fir16_state_t *fir)
  kfree(fir->history);
 }

-#ifdef __bfin__
-static inline int32_t dot_asm(short *x, short *y, int len)
-{
- int dot;
-
- len--;
-
- __asm__("I0 = %1;\n\t"
- "I1 = %2;\n\t"
- "A0 = 0;\n\t"
- "R0.L = W[I0++] || R1.L = W[I1++];\n\t"
- "LOOP dot%= LC0 = %3;\n\t"
- "LOOP_BEGIN dot%=;\n\t"
- "A0 += R0.L * R1.L (IS) || R0.L = W[I0++] || R1.L = W[I1++];\n\t"
- "LOOP_END dot%=;\n\t"
- "A0 += R0.L*R1.L (IS);\n\t"
- "R0 = A0;\n\t"
- "%0 = R0;\n\t"
- : "=&d"(dot)
- : "a"(x), "a"(y), "a"(len)
- : "I0", "I1", "A1", "A0", "R0", "R1"
- );
-
- return dot;
-}
-#endif
-
 static inline int16_t fir16(struct fir16_state_t *fir, int16_t sample)
 {
  int32_t y;
-#if defined(__bfin__)
- fir->history[fir->curr_pos] = sample;
- fir->history[fir->curr_pos + fir->taps] = sample;
- y = dot_asm((int16_t *) fir->coeffs, &fir->history[fir->curr_pos],
-     fir->taps);
-#else
  int i;
  int offset1;
  int offset2;
@@ -165,7 +116,6 @@ static inline int16_t fir16(struct fir16_state_t
*fir, int16_t sample)
  y += fir->coeffs[i] * fir->history[i - offset1];
  for (; i >= 0; i--)
  y += fir->coeffs[i] * fir->history[i + offset2];
-#endif
  if (fir->curr_pos <= 0)
  fir->curr_pos = fir->taps;
  fir->curr_pos--;
diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c
b/drivers/usb/gadget/function/f_uac1_legacy.c
index 04f4b2862256..24c086bcdeaa 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -4,8 +4,6 @@
   *
  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
  * Copyright (C) 2008 Analog Devices, Inc
- *
- * Enter bugs at http://blackfin.uclinux.org/
  */

 #include <linux/slab.h>
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.c
b/drivers/usb/gadget/function/u_uac1_legacy.c
index cbc868d117af..5393e5c37a4b 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.c
+++ b/drivers/usb/gadget/function/u_uac1_legacy.c
@@ -4,8 +4,6 @@
  *
  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
  * Copyright (C) 2008 Analog Devices, Inc
- *
- * Enter bugs at http://blackfin.uclinux.org/
  */

 #include <linux/kernel.h>
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.h
b/drivers/usb/gadget/function/u_uac1_legacy.h
index dd69e408a3d9..5c1bdf46fe32 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.h
+++ b/drivers/usb/gadget/function/u_uac1_legacy.h
@@ -4,8 +4,6 @@
  *
  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
  * Copyright (C) 2008 Analog Devices, Inc
- *
- * Enter bugs at http://blackfin.uclinux.org/
  */

 #ifndef __U_UAC1_LEGACY_H
diff --git a/drivers/usb/gadget/legacy/audio.c
b/drivers/usb/gadget/legacy/audio.c
index 7b11dce98b94..dd81fd538cb8 100644
--- a/drivers/usb/gadget/legacy/audio.c
+++ b/drivers/usb/gadget/legacy/audio.c
@@ -4,8 +4,6 @@
  *
  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
  * Copyright (C) 2008 Analog Devices, Inc
- *
- * Enter bugs at http://blackfin.uclinux.org/
  */

 /* #define VERBOSE_DEBUG */
diff --git a/drivers/usb/host/isp1362.h b/drivers/usb/host/isp1362.h
index 87c1ac97e538..650240846ee2 100644
--- a/drivers/usb/host/isp1362.h
+++ b/drivers/usb/host/isp1362.h
@@ -6,9 +6,7 @@
  */

 /* ------------------------------------------------------------------------- */
-/*
- * Platform specific compile time options
- */
+
 #define MAX_ROOT_PORTS 2

 #define USE_32BIT 0
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 011c8ca7de42..13486588e561 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2166,7 +2166,7 @@ musb_init_controller(struct device *dev, int
nIrq, void __iomem *ctrl)
  *   - initializes musb->xceiv, usually by otg_get_phy()
  *   - stops powering VBUS
  *
- * There are various transceiver configurations.  Blackfin,
+ * There are various transceiver configurations.
  * DaVinci, TUSB60x0, and others integrate them.  OMAP3 uses
  * external/discrete ones in various flavors (twl4030 family,
  * isp1504, non-OTG, etc) mostly hooking up through ULPI.
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index ac675b1a34c4..8a74cb2907f8 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -414,19 +414,6 @@ struct musb {
  struct usb_gadget_driver *gadget_driver; /* its driver */
  struct usb_hcd *hcd; /* the usb hcd */

- /*
- * FIXME: Remove this flag.
- *
- * This is only added to allow Blackfin to work
- * with current driver. For some unknown reason
- * Blackfin doesn't work with double buffering
- * and that's enabled by default.
- *
- * We added this flag to forcefully disable double
- * buffering until we get it working.
- */
- unsigned                double_buffer_not_ok:1;
-
  const struct musb_hdrc_config *config;

  int xceiv_old_state;
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 5b211fe295f0..8796ba387152 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -29,7 +29,6 @@ enum cpuhp_state {
  CPUHP_PERF_PREPARE,
  CPUHP_PERF_X86_PREPARE,
  CPUHP_PERF_X86_AMD_UNCORE_PREP,
- CPUHP_PERF_BFIN,
  CPUHP_PERF_POWER,
  CPUHP_PERF_SUPERH,
  CPUHP_X86_HPET_DEAD,
diff --git a/include/linux/fb.h b/include/linux/fb.h
index f577d3c89618..0c20da7ab35f 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -571,8 +571,7 @@ static inline struct apertures_struct
*alloc_apertures(unsigned int max_num) {

 #elif defined(__i386__) || defined(__alpha__) || defined(__x86_64__) || \
  defined(__hppa__) || defined(__sh__) || defined(__powerpc__) || \
- defined(__avr32__) || defined(__bfin__) || defined(__arm__) || \
- defined(__aarch64__)
+ defined(__avr32__) || defined(__arm__) || defined(__aarch64__)

 #define fb_readb __raw_readb
 #define fb_readw __raw_readw