[ALSA] Several fixes for the Sun DBRI driver

SPARC DBRI driver
This patch contains the following fixes to the Alsa DBRI driver:

- Remove 2.6.13 build warning on the prom_getproperty() call.

- Rework command synchronization: send a sequence number with D_WAIT,
  and check it in the completion interrupt.
  Move synchronization delays from _cmdsend() to _cmdlock() allowing the
  CPU to do other usefull things while the DBRI is processing the
  commands.

- Fix first argument of printk() calls.

- Enable burst transfers for DBRI. Original 2.4 patch from Krzysztof
  Helt

- Make dbri_debug module parameter writable from sysfs. Remove obsolete
  write access to the /proc debug file.

- Replace udelay() with msleep_interruptible() where possible.

- Update documentation comments.

Signed-off-by: Martin Habets <errandir_news@mph.eclipse.co.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 103 insertions, 102 deletions

diff --git a/sound/sparc/dbri.c b/sound/sparc/dbri.c
index a56f81bb0049..b5c4c15ae7f0 100644
--- a/sound/sparc/dbri.c
+++ b/sound/sparc/dbri.c
@@ -1,6 +1,6 @@
 /*
  * Driver for DBRI sound chip found on Sparcs.
- * Copyright (C) 2004 Martin Habets (mhabets@users.sourceforge.net)
+ * Copyright (C) 2004, 2005 Martin Habets (mhabets@users.sourceforge.net)
  *
  * Based entirely upon drivers/sbus/audio/dbri.c which is:
  * Copyright (C) 1997 Rudolf Koenig (rfkoenig@immd4.informatik.uni-erlangen.de)
@@ -43,6 +43,12 @@
  * audio devices. But the SUN HW group decided against it, at least on my
  * LX the speakerbox connector has at least 1 pin missing and 1 wrongly
  * connected.
+ *
+ * I've tried to stick to the following function naming conventions:
+ * snd_*        ALSA stuff
+ * cs4215_*     CS4215 codec specfic stuff
+ * dbri_*       DBRI high-level stuff
+ * other        DBRI low-level stuff
  */
 
 #include <sound/driver.h>
@@ -87,7 +93,7 @@ MODULE_PARM_DESC(enable, "Enable Sun DBRI soundcard.");
 #define D_DESC  (1<<5)
 
 static int dbri_debug = 0;
-module_param(dbri_debug, int, 0444);
+module_param(dbri_debug, int, 0644);
 MODULE_PARM_DESC(dbri_debug, "Debug value for Sun DBRI soundcard.");
 
 #ifdef DBRI_DEBUG
@@ -320,7 +326,8 @@ typedef struct snd_dbri {
         void __iomem *regs;     /* dbri HW regs */
         int dbri_version;       /* 'e' and up is OK */
         int dbri_irqp;          /* intr queue pointer */
-        int wait_seen;
+        int wait_send;          /* sequence of command buffers send */
+        int wait_ackd;          /* sequence of command buffers acknowledged */
 
         struct dbri_pipe pipes[DBRI_NO_PIPES];  /* DBRI's 32 data pipes */
         struct dbri_desc descs[DBRI_NO_DESCS];
@@ -625,16 +632,13 @@ static __u32 reverse_bytes(__u32 b, int len)
 
 Commands are sent to the DBRI by building a list of them in memory,
 then writing the address of the first list item to DBRI register 8.
-The list is terminated with a WAIT command, which can generate a
-CPU interrupt if required.
+The list is terminated with a WAIT command, which generates a
+CPU interrupt to signal completion.
 
 Since the DBRI can run in parallel with the CPU, several means of
-synchronization present themselves.  The original scheme (Rudolf's)
-was to set a flag when we "cmdlock"ed the DBRI, clear the flag when
-an interrupt signaled completion, and wait on a wait_queue if a routine
-attempted to cmdlock while the flag was set.  The problems arose when
-we tried to cmdlock from inside an interrupt handler, which might
-cause scheduling in an interrupt (if we waited), etc, etc
+synchronization present themselves.  The method implemented here is close
+to the original scheme (Rudolf's), and uses 2 counters (wait_send and
+wait_ackd) to synchronize the command buffer between the CPU and the DBRI.
 
 A more sophisticated scheme might involve a circular command buffer
 or an array of command buffers.  A routine could fill one with
@@ -642,70 +646,75 @@ commands and link it onto a list.  When a interrupt signaled
 completion of the current command buffer, look on the list for
 the next one.
 
-I've decided to implement something much simpler - after each command,
-the CPU waits for the DBRI to finish the command by polling the P bit
-in DBRI register 0.  I've tried to implement this in such a way
-that might make implementing a more sophisticated scheme easier.
-
 Every time a routine wants to write commands to the DBRI, it must
 first call dbri_cmdlock() and get an initial pointer into dbri->dma->cmd
-in return.  After the commands have been writen, dbri_cmdsend() is
-called with the final pointer value.
+in return. dbri_cmdlock() will block if the previous commands have not
+been completed yet. After this the commands can be written to the buffer,
+and dbri_cmdsend() is called with the final pointer value to send them
+to the DBRI.
 
 */
 
+static void dbri_process_interrupt_buffer(snd_dbri_t * dbri);
+
 enum dbri_lock_t { NoGetLock, GetLock };
+#define MAXLOOPS 10
 
 static volatile s32 *dbri_cmdlock(snd_dbri_t * dbri, enum dbri_lock_t get)
 {
+        int maxloops = MAXLOOPS;
+
 #ifndef SMP
         if ((get == GetLock) && spin_is_locked(&dbri->lock)) {
                 printk(KERN_ERR "DBRI: cmdlock called while in spinlock.");
         }
 #endif
 
+        /* Delay if previous commands are still being processed */
+        while ((--maxloops) > 0 && (dbri->wait_send != dbri->wait_ackd)) {
+                msleep_interruptible(1);
+                /* If dbri_cmdlock() got called from inside the
+                 * interrupt handler, this will do the processing.
+                 */
+                dbri_process_interrupt_buffer(dbri);
+        }
+        if (maxloops == 0) {
+                printk(KERN_ERR "DBRI: Chip never completed command buffer %d\n",
+                        dbri->wait_send);
+        } else {
+                dprintk(D_CMD, "Chip completed command buffer (%d)\n",
+                        MAXLOOPS - maxloops - 1);
+        }
+
         /*if (get == GetLock) spin_lock(&dbri->lock); */
         return &dbri->dma->cmd[0];
 }
 
-static void dbri_process_interrupt_buffer(snd_dbri_t *);
-
 static void dbri_cmdsend(snd_dbri_t * dbri, volatile s32 * cmd)
 {
-        int MAXLOOPS = 1000000;
-        int maxloops = MAXLOOPS;
         volatile s32 *ptr;
+        u32     reg;
 
         for (ptr = &dbri->dma->cmd[0]; ptr < cmd; ptr++) {
                 dprintk(D_CMD, "cmd: %lx:%08x\n", (unsigned long)ptr, *ptr);
         }
 
         if ((cmd - &dbri->dma->cmd[0]) >= DBRI_NO_CMDS - 1) {
-                printk("DBRI: Command buffer overflow! (bug in driver)\n");
+                printk(KERN_ERR "DBRI: Command buffer overflow! (bug in driver)\n");
                 /* Ignore the last part. */
                 cmd = &dbri->dma->cmd[DBRI_NO_CMDS - 3];
         }
 
+        dbri->wait_send++;
+        dbri->wait_send &= 0xffff;      /* restrict it to a 16 bit counter. */
         *(cmd++) = DBRI_CMD(D_PAUSE, 0, 0);
-        *(cmd++) = DBRI_CMD(D_WAIT, 1, 0);
-        dbri->wait_seen = 0;
+        *(cmd++) = DBRI_CMD(D_WAIT, 1, dbri->wait_send);
+
+        /* Set command pointer and signal it is valid. */
         sbus_writel(dbri->dma_dvma, dbri->regs + REG8);
-        while ((--maxloops) > 0 && (sbus_readl(dbri->regs + REG0) & D_P))
-                barrier();
-        if (maxloops == 0) {
-                printk(KERN_ERR "DBRI: Chip never completed command buffer\n");
-                dprintk(D_CMD, "DBRI: Chip never completed command buffer\n");
-        } else {
-                while ((--maxloops) > 0 && (!dbri->wait_seen))
-                        dbri_process_interrupt_buffer(dbri);
-                if (maxloops == 0) {
-                        printk(KERN_ERR "DBRI: Chip never acked WAIT\n");
-                        dprintk(D_CMD, "DBRI: Chip never acked WAIT\n");
-                } else {
-                        dprintk(D_CMD, "Chip completed command "
-                                "buffer (%d)\n", MAXLOOPS - maxloops);
-                }
-        }
+        reg = sbus_readl(dbri->regs + REG0);
+        reg |= D_P;
+        sbus_writel(reg, dbri->regs + REG0);
 
         /*spin_unlock(&dbri->lock); */
 }
@@ -757,10 +766,11 @@ static void dbri_initialize(snd_dbri_t * dbri)
         for (n = 0; n < DBRI_NO_PIPES; n++)
                 dbri->pipes[n].desc = dbri->pipes[n].first_desc = -1;
 
-        /* We should query the openprom to see what burst sizes this
-         * SBus supports.  For now, just disable all SBus bursts */
+        /* A brute approach - DBRI falls back to working burst size by itself
+         * On SS20 D_S does not work, so do not try so high. */
         tmp = sbus_readl(dbri->regs + REG0);
-        tmp &= ~(D_G | D_S | D_E);
+        tmp |= D_G | D_E;
+        tmp &= ~D_S;
         sbus_writel(tmp, dbri->regs + REG0);
 
         /*
@@ -805,13 +815,13 @@ static void reset_pipe(snd_dbri_t * dbri, int pipe)
         volatile int *cmd;
 
         if (pipe < 0 || pipe > 31) {
-                printk("DBRI: reset_pipe called with illegal pipe number\n");
+                printk(KERN_ERR "DBRI: reset_pipe called with illegal pipe number\n");
                 return;
         }
 
         sdp = dbri->pipes[pipe].sdp;
         if (sdp == 0) {
-                printk("DBRI: reset_pipe called on uninitialized pipe\n");
+                printk(KERN_ERR "DBRI: reset_pipe called on uninitialized pipe\n");
                 return;
         }
 
@@ -834,12 +844,12 @@ static void reset_pipe(snd_dbri_t * dbri, int pipe)
 static void setup_pipe(snd_dbri_t * dbri, int pipe, int sdp)
 {
         if (pipe < 0 || pipe > 31) {
-                printk("DBRI: setup_pipe called with illegal pipe number\n");
+                printk(KERN_ERR "DBRI: setup_pipe called with illegal pipe number\n");
                 return;
         }
 
         if ((sdp & 0xf800) != sdp) {
-                printk("DBRI: setup_pipe called with strange SDP value\n");
+                printk(KERN_ERR "DBRI: setup_pipe called with strange SDP value\n");
                 /* sdp &= 0xf800; */
         }
 
@@ -872,13 +882,13 @@ static void link_time_slot(snd_dbri_t * dbri, int pipe,
         int nextpipe;
 
         if (pipe < 0 || pipe > 31 || basepipe < 0 || basepipe > 31) {
-                printk
-                    ("DBRI: link_time_slot called with illegal pipe number\n");
+                printk(KERN_ERR 
+                    "DBRI: link_time_slot called with illegal pipe number\n");
                 return;
         }
 
         if (dbri->pipes[pipe].sdp == 0 || dbri->pipes[basepipe].sdp == 0) {
-                printk("DBRI: link_time_slot called on uninitialized pipe\n");
+                printk(KERN_ERR "DBRI: link_time_slot called on uninitialized pipe\n");
                 return;
         }
 
@@ -960,8 +970,8 @@ static void unlink_time_slot(snd_dbri_t * dbri, int pipe,
         int val;
 
         if (pipe < 0 || pipe > 31 || prevpipe < 0 || prevpipe > 31) {
-                printk
-                    ("DBRI: unlink_time_slot called with illegal pipe number\n");
+                printk(KERN_ERR 
+                    "DBRI: unlink_time_slot called with illegal pipe number\n");
                 return;
         }
 
@@ -1001,22 +1011,22 @@ static void xmit_fixed(snd_dbri_t * dbri, int pipe, unsigned int data)
         volatile s32 *cmd;
 
         if (pipe < 16 || pipe > 31) {
-                printk("DBRI: xmit_fixed: Illegal pipe number\n");
+                printk(KERN_ERR "DBRI: xmit_fixed: Illegal pipe number\n");
                 return;
         }
 
         if (D_SDP_MODE(dbri->pipes[pipe].sdp) == 0) {
-                printk("DBRI: xmit_fixed: Uninitialized pipe %d\n", pipe);
+                printk(KERN_ERR "DBRI: xmit_fixed: Uninitialized pipe %d\n", pipe);
                 return;
         }
 
         if (D_SDP_MODE(dbri->pipes[pipe].sdp) != D_SDP_FIXED) {
-                printk("DBRI: xmit_fixed: Non-fixed pipe %d\n", pipe);
+                printk(KERN_ERR "DBRI: xmit_fixed: Non-fixed pipe %d\n", pipe);
                 return;
         }
 
         if (!(dbri->pipes[pipe].sdp & D_SDP_TO_SER)) {
-                printk("DBRI: xmit_fixed: Called on receive pipe %d\n", pipe);
+                printk(KERN_ERR "DBRI: xmit_fixed: Called on receive pipe %d\n", pipe);
                 return;
         }
 
@@ -1036,17 +1046,17 @@ static void xmit_fixed(snd_dbri_t * dbri, int pipe, unsigned int data)
 static void recv_fixed(snd_dbri_t * dbri, int pipe, volatile __u32 * ptr)
 {
         if (pipe < 16 || pipe > 31) {
-                printk("DBRI: recv_fixed called with illegal pipe number\n");
+                printk(KERN_ERR "DBRI: recv_fixed called with illegal pipe number\n");
                 return;
         }
 
         if (D_SDP_MODE(dbri->pipes[pipe].sdp) != D_SDP_FIXED) {
-                printk("DBRI: recv_fixed called on non-fixed pipe %d\n", pipe);
+                printk(KERN_ERR "DBRI: recv_fixed called on non-fixed pipe %d\n", pipe);
                 return;
         }
 
         if (dbri->pipes[pipe].sdp & D_SDP_TO_SER) {
-                printk("DBRI: recv_fixed called on transmit pipe %d\n", pipe);
+                printk(KERN_ERR "DBRI: recv_fixed called on transmit pipe %d\n", pipe);
                 return;
         }
 
@@ -1075,12 +1085,12 @@ static int setup_descs(snd_dbri_t * dbri, int streamno, unsigned int period)
         int last_desc = -1;
 
         if (info->pipe < 0 || info->pipe > 15) {
-                printk("DBRI: setup_descs: Illegal pipe number\n");
+                printk(KERN_ERR "DBRI: setup_descs: Illegal pipe number\n");
                 return -2;
         }
 
         if (dbri->pipes[info->pipe].sdp == 0) {
-                printk("DBRI: setup_descs: Uninitialized pipe %d\n",
+                printk(KERN_ERR "DBRI: setup_descs: Uninitialized pipe %d\n",
                        info->pipe);
                 return -2;
         }
@@ -1090,20 +1100,20 @@ static int setup_descs(snd_dbri_t * dbri, int streamno, unsigned int period)
 
         if (streamno == DBRI_PLAY) {
                 if (!(dbri->pipes[info->pipe].sdp & D_SDP_TO_SER)) {
-                        printk("DBRI: setup_descs: Called on receive pipe %d\n",
+                        printk(KERN_ERR "DBRI: setup_descs: Called on receive pipe %d\n",
                                info->pipe);
                         return -2;
                 }
         } else {
                 if (dbri->pipes[info->pipe].sdp & D_SDP_TO_SER) {
-                        printk
-                            ("DBRI: setup_descs: Called on transmit pipe %d\n",
+                        printk(KERN_ERR 
+                            "DBRI: setup_descs: Called on transmit pipe %d\n",
                              info->pipe);
                         return -2;
                 }
                 /* Should be able to queue multiple buffers to receive on a pipe */
                 if (pipe_active(dbri, info->pipe)) {
-                        printk("DBRI: recv_on_pipe: Called on active pipe %d\n",
+                        printk(KERN_ERR "DBRI: recv_on_pipe: Called on active pipe %d\n",
                                info->pipe);
                         return -2;
                 }
@@ -1120,7 +1130,7 @@ static int setup_descs(snd_dbri_t * dbri, int streamno, unsigned int period)
                                 break;
                 }
                 if (desc == DBRI_NO_DESCS) {
-                        printk("DBRI: setup_descs: No descriptors\n");
+                        printk(KERN_ERR "DBRI: setup_descs: No descriptors\n");
                         return -1;
                 }
 
@@ -1165,7 +1175,7 @@ static int setup_descs(snd_dbri_t * dbri, int streamno, unsigned int period)
         }
 
         if (first_desc == -1 || last_desc == -1) {
-                printk("DBRI: setup_descs: Not enough descriptors available\n");
+                printk(KERN_ERR "DBRI: setup_descs: Not enough descriptors available\n");
                 return -1;
         }
 
@@ -1270,7 +1280,7 @@ static void reset_chi(snd_dbri_t * dbri, enum master_or_slave master_or_slave,
                 int divisor = 12288 / clockrate;
 
                 if (divisor > 255 || divisor * clockrate != 12288)
-                        printk("DBRI: illegal bits_per_frame in setup_chi\n");
+                        printk(KERN_ERR "DBRI: illegal bits_per_frame in setup_chi\n");
 
                 *(cmd++) = DBRI_CMD(D_CHI, 0, D_CHI_CHICM(divisor) | D_CHI_FD
                                     | D_CHI_BPF(bits_per_frame));
@@ -1474,7 +1484,6 @@ static int cs4215_setctrl(snd_dbri_t * dbri)
         /* Temporarily mute outputs, and wait 1/8000 sec (125 us)
          * to make sure this takes.  This avoids clicking noises.
          */
-
         cs4215_setdata(dbri, 1);
         udelay(125);
 
@@ -1530,8 +1539,8 @@ static int cs4215_setctrl(snd_dbri_t * dbri)
         tmp |= D_C;             /* Enable CHI */
         sbus_writel(tmp, dbri->regs + REG0);
 
-        for (i = 64; ((dbri->mm.status & 0xe4) != 0x20); --i) {
-                udelay(125);
+        for (i = 10; ((dbri->mm.status & 0xe4) != 0x20); --i) {
+                msleep_interruptible(1);
         }
         if (i == 0) {
                 dprintk(D_MM, "CS4215 didn't respond to CLB (0x%02x)\n",
@@ -1678,8 +1687,8 @@ buffer and calls dbri_process_one_interrupt() for each interrupt word.
 Complicated interrupts are handled by dedicated functions (which
 appear first in this file).  Any pending interrupts can be serviced by
 calling dbri_process_interrupt_buffer(), which works even if the CPU's
-interrupts are disabled.  This function is used by dbri_cmdsend()
-to make sure we're synced up with the chip after each command sequence,
+interrupts are disabled.  This function is used by dbri_cmdlock()
+to make sure we're synced up with the chip before each command sequence,
 even if we're running cli'ed.
 
 */
@@ -1765,11 +1774,13 @@ DECLARE_TASKLET(xmit_descs_task, xmit_descs, 0);
  * Called by main interrupt handler when DBRI signals transmission complete
  * on a pipe (interrupt triggered by the B bit in a transmit descriptor).
  *
- * Walks through the pipe's list of transmit buffer descriptors, releasing
- * each one's DMA buffer (if present), flagging the descriptor available,
- * and signaling its callback routine (if present), before proceeding
- * to the next one.  Stops when the first descriptor is found without
+ * Walks through the pipe's list of transmit buffer descriptors and marks
+ * them as available. Stops when the first descriptor is found without
  * TBC (Transmit Buffer Complete) set, or we've run through them all.
+ *
+ * The DMA buffers are not released, but re-used. Since the transmit buffer
+ * descriptors are not clobbered, they can be re-submitted as is. This is
+ * done by the xmit_descs() tasklet above since that could take longer.
  */
 
 static void transmission_complete_intr(snd_dbri_t * dbri, int pipe)
@@ -1885,7 +1896,11 @@ static void dbri_process_one_interrupt(snd_dbri_t * dbri, int x)
         }
 
         if (channel == D_INTR_CMD && command == D_WAIT) {
-                dbri->wait_seen++;
+                dbri->wait_ackd = val;
+                if (dbri->wait_send != val) {
+                        printk(KERN_ERR "Processing wait command %d when %d was send.\n",
+                               val, dbri->wait_send);
+                }
                 return;
         }
 
@@ -1994,8 +2009,7 @@ static irqreturn_t snd_dbri_interrupt(int irq, void *dev_id,
                  * The only one I've seen is MRR, which will be triggered
                  * if you let a transmit pipe underrun, then try to CDP it.
                  *
-                 * If these things persist, we should probably reset
-                 * and re-init the chip.
+                 * If these things persist, we reset the chip.
                  */
                 if ((++errcnt) % 10 == 0) {
                         dprintk(D_INT, "Interrupt errors exceeded.\n");
@@ -2094,7 +2108,7 @@ static int snd_dbri_hw_params(snd_pcm_substream_t * substream,
 
         if ((ret = snd_pcm_lib_malloc_pages(substream,
                                 params_buffer_bytes(hw_params))) < 0) {
-                snd_printk(KERN_ERR "malloc_pages failed with %d\n", ret);
+                printk(KERN_ERR "malloc_pages failed with %d\n", ret);
                 return ret;
         }
 
@@ -2455,8 +2469,7 @@ static int __init snd_dbri_mixer(snd_dbri_t * dbri)
 
         for (idx = 0; idx < NUM_CS4215_CONTROLS; idx++) {
                 if ((err = snd_ctl_add(card,
-                                       snd_ctl_new1(&dbri_controls[idx],
-                                                    dbri))) < 0)
+                                snd_ctl_new1(&dbri_controls[idx], dbri))) < 0)
                         return err;
         }
 
@@ -2490,8 +2503,6 @@ static void dbri_debug_read(snd_info_entry_t * entry,
         int pipe;
         snd_iprintf(buffer, "debug=%d\n", dbri_debug);
 
-        snd_iprintf(buffer, "CHI pipe in=%d, out=%d\n",
-                    dbri->chi_in_pipe, dbri->chi_out_pipe);
         for (pipe = 0; pipe < 32; pipe++) {
                 if (pipe_active(dbri, pipe)) {
                         struct dbri_pipe *pptr = &dbri->pipes[pipe];
@@ -2506,18 +2517,6 @@ static void dbri_debug_read(snd_info_entry_t * entry,
                 }
         }
 }
-
-static void dbri_debug_write(snd_info_entry_t * entry,
-                             snd_info_buffer_t * buffer)
-{
-        char line[80];
-        int i;
-
-        if (snd_info_get_line(buffer, line, 80) == 0) {
-                sscanf(line, "%d\n", &i);
-                dbri_debug = i & 0x3f;
-        }
-}
 #endif
 
 void snd_dbri_proc(snd_dbri_t * dbri)
@@ -2531,9 +2530,7 @@ void snd_dbri_proc(snd_dbri_t * dbri)
 #ifdef DBRI_DEBUG
         err = snd_card_proc_new(dbri->card, "debug", &entry);
         snd_info_set_text_ops(entry, dbri, 4096, dbri_debug_read);
-        entry->mode = S_IFREG | S_IRUGO | S_IWUSR; /* Writable for root */
-        entry->c.text.write_size = 256;
-        entry->c.text.write = dbri_debug_write;
+        entry->mode = S_IFREG | S_IRUGO;        /* Readable only. */
 #endif
 }
 
@@ -2637,7 +2634,11 @@ static int __init dbri_attach(int prom_node, struct sbus_dev *sdev)
                 return -ENOENT;
         }
 
-        prom_getproperty(prom_node, "intr", (char *)&irq, sizeof(irq));
+        err = prom_getproperty(prom_node, "intr", (char *)&irq, sizeof(irq));
+        if (err < 0) {
+                printk(KERN_ERR "DBRI-%d: Firmware node lacks IRQ property.\n", dev);
+                return -ENODEV;
+        }
 
         card = snd_card_new(index[dev], id[dev], THIS_MODULE,
                             sizeof(snd_dbri_t));