ath5k: HW code cleanup

 * No code changes...

 * Split hw.c to multiple files for better maintenance and add some documentation on each file
   code is going to grow soon (eeprom.c for example is going to get much stuff currently developed
   on ath_info) so it's better this way.

 * Rename following functions to maintain naming scheme:

     ah_setup_xtx_desc -> ah_setup_mrr_tx_desc
     (Because xtx doesn't say much, it's actually
     a multi-rate-retry tx descriptor)

     ath5k_hw_put_tx/rx_buf - > ath5k_hw_set_tx/rxdp
     ath5k_hw_get_tx/rx_buf -> ath5k_hw_get_tx/rxdp
     (We don't put any "buf" we set descriptor pointers on hw)

     ath5k_hw_tx_start -> ath5k_hw_start_tx_dma
     ath5k_hw_start_rx -> ath5k_hw_start_rx_dma
     ath5k_hw_stop_pcu_recv -> ath5k_hw_stop_rx_pcu
     (It's easier this way to identify them, we also
     have ath5k_hw_start_rx_pcu which completes the
     set)

     ath5k_hw_set_intr -> ath5k_hw_set_imr
     (As in get_isr we set imr here, not "intr")

  * Move ath5k_hw_setup_rx_desc on ah->ah_setup_rx_desc so we can
    include support for different rx descriptors in the future

  * Further cleanups so that checkpatch doesn't complain
    (only some > 80 col warnings for eeprom.h and reg.h as usual
    due to comments)

  Tested on 5211 and 5213 cards and works ok.

Changes-licensed-under: ISC
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Acked-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 566 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath5k/dma.c b/drivers/net/wireless/ath5k/dma.c
new file mode 100644
index 000000000000..a28090be9603
--- /dev/null
+++ b/drivers/net/wireless/ath5k/dma.c
@@ -0,0 +1,566 @@
+/*
+ * Copyright (c) 2004-2008 Reyk Floeter <reyk@openbsd.org>
+ * Copyright (c) 2006-2008 Nick Kossifidis <mickflemm@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+/*************************************\
+* DMA and interrupt masking functions *
+\*************************************/
+
+/*
+ * dma.c - DMA and interrupt masking functions
+ *
+ * Here we setup descriptor pointers (rxdp/txdp) start/stop dma engine and
+ * handle queue setup for 5210 chipset (rest are handled on qcu.c).
+ * Also we setup interrupt mask register (IMR) and read the various iterrupt
+ * status registers (ISR).
+ *
+ * TODO: Handle SISR on 5211+ and introduce a function to return the queue
+ * number that resulted the interrupt.
+ */
+
+#include "ath5k.h"
+#include "reg.h"
+#include "debug.h"
+#include "base.h"
+
+/*********\
+* Receive *
+\*********/
+
+/**
+ * ath5k_hw_start_rx_dma - Start DMA receive
+ *
+ * @ah: The &struct ath5k_hw
+ */
+void ath5k_hw_start_rx_dma(struct ath5k_hw *ah)
+{
+        ATH5K_TRACE(ah->ah_sc);
+        ath5k_hw_reg_write(ah, AR5K_CR_RXE, AR5K_CR);
+        ath5k_hw_reg_read(ah, AR5K_CR);
+}
+
+/**
+ * ath5k_hw_stop_rx_dma - Stop DMA receive
+ *
+ * @ah: The &struct ath5k_hw
+ */
+int ath5k_hw_stop_rx_dma(struct ath5k_hw *ah)
+{
+        unsigned int i;
+
+        ATH5K_TRACE(ah->ah_sc);
+        ath5k_hw_reg_write(ah, AR5K_CR_RXD, AR5K_CR);
+
+        /*
+         * It may take some time to disable the DMA receive unit
+         */
+        for (i = 2000; i > 0 &&
+                        (ath5k_hw_reg_read(ah, AR5K_CR) & AR5K_CR_RXE) != 0;
+                        i--)
+                udelay(10);
+
+        return i ? 0 : -EBUSY;
+}
+
+/**
+ * ath5k_hw_get_rxdp - Get RX Descriptor's address
+ *
+ * @ah: The &struct ath5k_hw
+ *
+ * XXX: Is RXDP read and clear ?
+ */
+u32 ath5k_hw_get_rxdp(struct ath5k_hw *ah)
+{
+        return ath5k_hw_reg_read(ah, AR5K_RXDP);
+}
+
+/**
+ * ath5k_hw_set_rxdp - Set RX Descriptor's address
+ *
+ * @ah: The &struct ath5k_hw
+ * @phys_addr: RX descriptor address
+ *
+ * XXX: Should we check if rx is enabled before setting rxdp ?
+ */
+void ath5k_hw_set_rxdp(struct ath5k_hw *ah, u32 phys_addr)
+{
+        ATH5K_TRACE(ah->ah_sc);
+
+        ath5k_hw_reg_write(ah, phys_addr, AR5K_RXDP);
+}
+
+
+/**********\
+* Transmit *
+\**********/
+
+/**
+ * ath5k_hw_start_tx_dma - Start DMA transmit for a specific queue
+ *
+ * @ah: The &struct ath5k_hw
+ * @queue: The hw queue number
+ *
+ * Start DMA transmit for a specific queue and since 5210 doesn't have
+ * QCU/DCU, set up queue parameters for 5210 here based on queue type (one
+ * queue for normal data and one queue for beacons). For queue setup
+ * on newer chips check out qcu.c. Returns -EINVAL if queue number is out
+ * of range or if queue is already disabled.
+ *
+ * NOTE: Must be called after setting up tx control descriptor for that
+ * queue (see below).
+ */
+int ath5k_hw_start_tx_dma(struct ath5k_hw *ah, unsigned int queue)
+{
+        u32 tx_queue;
+
+        ATH5K_TRACE(ah->ah_sc);
+        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
+
+        /* Return if queue is declared inactive */
+        if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
+                return -EIO;
+
+        if (ah->ah_version == AR5K_AR5210) {
+                tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);
+
+                /*
+                 * Set the queue by type on 5210
+                 */
+                switch (ah->ah_txq[queue].tqi_type) {
+                case AR5K_TX_QUEUE_DATA:
+                        tx_queue |= AR5K_CR_TXE0 & ~AR5K_CR_TXD0;
+                        break;
+                case AR5K_TX_QUEUE_BEACON:
+                        tx_queue |= AR5K_CR_TXE1 & ~AR5K_CR_TXD1;
+                        ath5k_hw_reg_write(ah, AR5K_BCR_TQ1V | AR5K_BCR_BDMAE,
+                                        AR5K_BSR);
+                        break;
+                case AR5K_TX_QUEUE_CAB:
+                        tx_queue |= AR5K_CR_TXE1 & ~AR5K_CR_TXD1;
+                        ath5k_hw_reg_write(ah, AR5K_BCR_TQ1FV | AR5K_BCR_TQ1V |
+                                AR5K_BCR_BDMAE, AR5K_BSR);
+                        break;
+                default:
+                        return -EINVAL;
+                }
+                /* Start queue */
+                ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
+                ath5k_hw_reg_read(ah, AR5K_CR);
+        } else {
+                /* Return if queue is disabled */
+                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXD, queue))
+                        return -EIO;
+
+                /* Start queue */
+                AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXE, queue);
+        }
+
+        return 0;
+}
+
+/**
+ * ath5k_hw_stop_tx_dma - Stop DMA transmit on a specific queue
+ *
+ * @ah: The &struct ath5k_hw
+ * @queue: The hw queue number
+ *
+ * Stop DMA transmit on a specific hw queue and drain queue so we don't
+ * have any pending frames. Returns -EBUSY if we still have pending frames,
+ * -EINVAL if queue number is out of range.
+ *
+ * TODO: Test queue drain code
+ */
+int ath5k_hw_stop_tx_dma(struct ath5k_hw *ah, unsigned int queue)
+{
+        unsigned int i = 100;
+        u32 tx_queue, pending;
+
+        ATH5K_TRACE(ah->ah_sc);
+        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
+
+        /* Return if queue is declared inactive */
+        if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
+                return -EIO;
+
+        if (ah->ah_version == AR5K_AR5210) {
+                tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);
+
+                /*
+                 * Set by queue type
+                 */
+                switch (ah->ah_txq[queue].tqi_type) {
+                case AR5K_TX_QUEUE_DATA:
+                        tx_queue |= AR5K_CR_TXD0 & ~AR5K_CR_TXE0;
+                        break;
+                case AR5K_TX_QUEUE_BEACON:
+                case AR5K_TX_QUEUE_CAB:
+                        /* XXX Fix me... */
+                        tx_queue |= AR5K_CR_TXD1 & ~AR5K_CR_TXD1;
+                        ath5k_hw_reg_write(ah, 0, AR5K_BSR);
+                        break;
+                default:
+                        return -EINVAL;
+                }
+
+                /* Stop queue */
+                ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
+                ath5k_hw_reg_read(ah, AR5K_CR);
+        } else {
+                /*
+                 * Schedule TX disable and wait until queue is empty
+                 */
+                AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXD, queue);
+
+                /*Check for pending frames*/
+                do {
+                        pending = ath5k_hw_reg_read(ah,
+                                AR5K_QUEUE_STATUS(queue)) &
+                                AR5K_QCU_STS_FRMPENDCNT;
+                        udelay(100);
+                } while (--i && pending);
+
+                /* Clear register */
+                ath5k_hw_reg_write(ah, 0, AR5K_QCU_TXD);
+                if (pending)
+                        return -EBUSY;
+        }
+
+        /* TODO: Check for success else return error */
+        return 0;
+}
+
+/**
+ * ath5k_hw_get_txdp - Get TX Descriptor's address for a specific queue
+ *
+ * @ah: The &struct ath5k_hw
+ * @queue: The hw queue number
+ *
+ * Get TX descriptor's address for a specific queue. For 5210 we ignore
+ * the queue number and use tx queue type since we only have 2 queues.
+ * We use TXDP0 for normal data queue and TXDP1 for beacon queue.
+ * For newer chips with QCU/DCU we just read the corresponding TXDP register.
+ *
+ * XXX: Is TXDP read and clear ?
+ */
+u32 ath5k_hw_get_txdp(struct ath5k_hw *ah, unsigned int queue)
+{
+        u16 tx_reg;
+
+        ATH5K_TRACE(ah->ah_sc);
+        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
+
+        /*
+         * Get the transmit queue descriptor pointer from the selected queue
+         */
+        /*5210 doesn't have QCU*/
+        if (ah->ah_version == AR5K_AR5210) {
+                switch (ah->ah_txq[queue].tqi_type) {
+                case AR5K_TX_QUEUE_DATA:
+                        tx_reg = AR5K_NOQCU_TXDP0;
+                        break;
+                case AR5K_TX_QUEUE_BEACON:
+                case AR5K_TX_QUEUE_CAB:
+                        tx_reg = AR5K_NOQCU_TXDP1;
+                        break;
+                default:
+                        return 0xffffffff;
+                }
+        } else {
+                tx_reg = AR5K_QUEUE_TXDP(queue);
+        }
+
+        return ath5k_hw_reg_read(ah, tx_reg);
+}
+
+/**
+ * ath5k_hw_set_txdp - Set TX Descriptor's address for a specific queue
+ *
+ * @ah: The &struct ath5k_hw
+ * @queue: The hw queue number
+ *
+ * Set TX descriptor's address for a specific queue. For 5210 we ignore
+ * the queue number and we use tx queue type since we only have 2 queues
+ * so as above we use TXDP0 for normal data queue and TXDP1 for beacon queue.
+ * For newer chips with QCU/DCU we just set the corresponding TXDP register.
+ * Returns -EINVAL if queue type is invalid for 5210 and -EIO if queue is still
+ * active.
+ */
+int ath5k_hw_set_txdp(struct ath5k_hw *ah, unsigned int queue, u32 phys_addr)
+{
+        u16 tx_reg;
+
+        ATH5K_TRACE(ah->ah_sc);
+        AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
+
+        /*
+         * Set the transmit queue descriptor pointer register by type
+         * on 5210
+         */
+        if (ah->ah_version == AR5K_AR5210) {
+                switch (ah->ah_txq[queue].tqi_type) {
+                case AR5K_TX_QUEUE_DATA:
+                        tx_reg = AR5K_NOQCU_TXDP0;
+                        break;
+                case AR5K_TX_QUEUE_BEACON:
+                case AR5K_TX_QUEUE_CAB:
+                        tx_reg = AR5K_NOQCU_TXDP1;
+                        break;
+                default:
+                        return -EINVAL;
+                }
+        } else {
+                /*
+                 * Set the transmit queue descriptor pointer for
+                 * the selected queue on QCU for 5211+
+                 * (this won't work if the queue is still active)
+                 */
+                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue))
+                        return -EIO;
+
+                tx_reg = AR5K_QUEUE_TXDP(queue);
+        }
+
+        /* Set descriptor pointer */
+        ath5k_hw_reg_write(ah, phys_addr, tx_reg);
+
+        return 0;
+}
+
+/**
+ * ath5k_hw_update_tx_triglevel - Update tx trigger level
+ *
+ * @ah: The &struct ath5k_hw
+ * @increase: Flag to force increase of trigger level
+ *
+ * This function increases/decreases the tx trigger level for the tx fifo
+ * buffer (aka FIFO threshold) that is used to indicate when PCU flushes
+ * the buffer and transmits it's data. Lowering this results sending small
+ * frames more quickly but can lead to tx underruns, raising it a lot can
+ * result other problems (i think bmiss is related). Right now we start with
+ * the lowest possible (64Bytes) and if we get tx underrun we increase it using
+ * the increase flag. Returns -EIO if we have have reached maximum/minimum.
+ *
+ * XXX: Link this with tx DMA size ?
+ * XXX: Use it to save interrupts ?
+ * TODO: Needs testing, i think it's related to bmiss...
+ */
+int ath5k_hw_update_tx_triglevel(struct ath5k_hw *ah, bool increase)
+{
+        u32 trigger_level, imr;
+        int ret = -EIO;
+
+        ATH5K_TRACE(ah->ah_sc);
+
+        /*
+         * Disable interrupts by setting the mask
+         */
+        imr = ath5k_hw_set_imr(ah, ah->ah_imr & ~AR5K_INT_GLOBAL);
+
+        trigger_level = AR5K_REG_MS(ath5k_hw_reg_read(ah, AR5K_TXCFG),
+                        AR5K_TXCFG_TXFULL);
+
+        if (!increase) {
+                if (--trigger_level < AR5K_TUNE_MIN_TX_FIFO_THRES)
+                        goto done;
+        } else
+                trigger_level +=
+                        ((AR5K_TUNE_MAX_TX_FIFO_THRES - trigger_level) / 2);
+
+        /*
+         * Update trigger level on success
+         */
+        if (ah->ah_version == AR5K_AR5210)
+                ath5k_hw_reg_write(ah, trigger_level, AR5K_TRIG_LVL);
+        else
+                AR5K_REG_WRITE_BITS(ah, AR5K_TXCFG,
+                                AR5K_TXCFG_TXFULL, trigger_level);
+
+        ret = 0;
+
+done:
+        /*
+         * Restore interrupt mask
+         */
+        ath5k_hw_set_imr(ah, imr);
+
+        return ret;
+}
+
+/*******************\
+* Interrupt masking *
+\*******************/
+
+/**
+ * ath5k_hw_is_intr_pending - Check if we have pending interrupts
+ *
+ * @ah: The &struct ath5k_hw
+ *
+ * Check if we have pending interrupts to process. Returns 1 if we
+ * have pending interrupts and 0 if we haven't.
+ */
+bool ath5k_hw_is_intr_pending(struct ath5k_hw *ah)
+{
+        ATH5K_TRACE(ah->ah_sc);
+        return ath5k_hw_reg_read(ah, AR5K_INTPEND);
+}
+
+/**
+ * ath5k_hw_get_isr - Get interrupt status
+ *
+ * @ah: The @struct ath5k_hw
+ * @interrupt_mask: Driver's interrupt mask used to filter out
+ * interrupts in sw.
+ *
+ * This function is used inside our interrupt handler to determine the reason
+ * for the interrupt by reading Primary Interrupt Status Register. Returns an
+ * abstract interrupt status mask which is mostly ISR with some uncommon bits
+ * being mapped on some standard non hw-specific positions
+ * (check out &ath5k_int).
+ *
+ * NOTE: We use read-and-clear register, so after this function is called ISR
+ * is zeroed.
+ *
+ * XXX: Why filter interrupts in sw with interrupt_mask ? No benefit at all
+ * plus it can be misleading (one might thing that we save interrupts this way)
+ */
+int ath5k_hw_get_isr(struct ath5k_hw *ah, enum ath5k_int *interrupt_mask)
+{
+        u32 data;
+
+        ATH5K_TRACE(ah->ah_sc);
+
+        /*
+         * Read interrupt status from the Interrupt Status register
+         * on 5210
+         */
+        if (ah->ah_version == AR5K_AR5210) {
+                data = ath5k_hw_reg_read(ah, AR5K_ISR);
+                if (unlikely(data == AR5K_INT_NOCARD)) {
+                        *interrupt_mask = data;
+                        return -ENODEV;
+                }
+        } else {
+                /*
+                 * Read interrupt status from the Read-And-Clear
+                 * shadow register.
+                 * Note: PISR/SISR Not available on 5210
+                 */
+                data = ath5k_hw_reg_read(ah, AR5K_RAC_PISR);
+        }
+
+        /*
+         * Get abstract interrupt mask (driver-compatible)
+         */
+        *interrupt_mask = (data & AR5K_INT_COMMON) & ah->ah_imr;
+
+        if (unlikely(data == AR5K_INT_NOCARD))
+                return -ENODEV;
+
+        if (data & (AR5K_ISR_RXOK | AR5K_ISR_RXERR))
+                *interrupt_mask |= AR5K_INT_RX;
+
+        if (data & (AR5K_ISR_TXOK | AR5K_ISR_TXERR
+                | AR5K_ISR_TXDESC | AR5K_ISR_TXEOL))
+                *interrupt_mask |= AR5K_INT_TX;
+
+        if (ah->ah_version != AR5K_AR5210) {
+                /*HIU = Host Interface Unit (PCI etc)*/
+                if (unlikely(data & (AR5K_ISR_HIUERR)))
+                        *interrupt_mask |= AR5K_INT_FATAL;
+
+                /*Beacon Not Ready*/
+                if (unlikely(data & (AR5K_ISR_BNR)))
+                        *interrupt_mask |= AR5K_INT_BNR;
+        }
+
+        /*
+         * XXX: BMISS interrupts may occur after association.
+         * I found this on 5210 code but it needs testing. If this is
+         * true we should disable them before assoc and re-enable them
+         * after a successfull assoc + some jiffies.
+         */
+#if 0
+        interrupt_mask &= ~AR5K_INT_BMISS;
+#endif
+
+        /*
+         * In case we didn't handle anything,
+         * print the register value.
+         */
+        if (unlikely(*interrupt_mask == 0 && net_ratelimit()))
+                ATH5K_PRINTF("0x%08x\n", data);
+
+        return 0;
+}
+
+/**
+ * ath5k_hw_set_imr - Set interrupt mask
+ *
+ * @ah: The &struct ath5k_hw
+ * @new_mask: The new interrupt mask to be set
+ *
+ * Set the interrupt mask in hw to save interrupts. We do that by mapping
+ * ath5k_int bits to hw-specific bits to remove abstraction and writing
+ * Interrupt Mask Register.
+ */
+enum ath5k_int ath5k_hw_set_imr(struct ath5k_hw *ah, enum ath5k_int new_mask)
+{
+        enum ath5k_int old_mask, int_mask;
+
+        /*
+         * Disable card interrupts to prevent any race conditions
+         * (they will be re-enabled afterwards).
+         */
+        ath5k_hw_reg_write(ah, AR5K_IER_DISABLE, AR5K_IER);
+        ath5k_hw_reg_read(ah, AR5K_IER);
+
+        old_mask = ah->ah_imr;
+
+        /*
+         * Add additional, chipset-dependent interrupt mask flags
+         * and write them to the IMR (interrupt mask register).
+         */
+        int_mask = new_mask & AR5K_INT_COMMON;
+
+        if (new_mask & AR5K_INT_RX)
+                int_mask |= AR5K_IMR_RXOK | AR5K_IMR_RXERR | AR5K_IMR_RXORN |
+                        AR5K_IMR_RXDESC;
+
+        if (new_mask & AR5K_INT_TX)
+                int_mask |= AR5K_IMR_TXOK | AR5K_IMR_TXERR | AR5K_IMR_TXDESC |
+                        AR5K_IMR_TXURN;
+
+        if (ah->ah_version != AR5K_AR5210) {
+                if (new_mask & AR5K_INT_FATAL) {
+                        int_mask |= AR5K_IMR_HIUERR;
+                        AR5K_REG_ENABLE_BITS(ah, AR5K_SIMR2, AR5K_SIMR2_MCABT |
+                                        AR5K_SIMR2_SSERR | AR5K_SIMR2_DPERR);
+                }
+        }
+
+        ath5k_hw_reg_write(ah, int_mask, AR5K_PIMR);
+
+        /* Store new interrupt mask */
+        ah->ah_imr = new_mask;
+
+        /* ..re-enable interrupts */
+        ath5k_hw_reg_write(ah, AR5K_IER_ENABLE, AR5K_IER);
+        ath5k_hw_reg_read(ah, AR5K_IER);
+
+        return old_mask;
+}
+