shift exponent 35 is too large @ ath/ath9k/ar9003_hw.c:1147

[Gregg Wonderly <greggwonderly@seqtechllc.com>]

I am receiving a console error message from this driver that appears to be in the following function.  In this function, the chk_dbg variable is 32bits and there is logic that seems to attempt to select from 1 of 2 different 32bit values to get a 64bit wide mask value into chk_dbg from dma_dbg_4 or dmc_dbg_5.

The problem is that the (5*i) shift count should be have i adjusted by the 6 limit used to make the check for which dma_dbg_[45] value selected.


static bool ar9003_hw_detect_mac_hang(struct ath_hw *ah)
{
	u32 dma_dbg_4, dma_dbg_5, dma_dbg_6, chk_dbg;
	u8 dcu_chain_state, dcu_complete_state;
	bool dcu_wait_frdone = false;
	unsigned long chk_dcu = 0;
	unsigned int i = 0;
	dma_dbg_4 = REG_READ(ah, AR_DMADBG_4);
	dma_dbg_5 = REG_READ(ah, AR_DMADBG_5);
	dma_dbg_6 = REG_READ(ah, AR_DMADBG_6);
	dcu_complete_state = dma_dbg_6 & 0x3;
	if (dcu_complete_state != 0x1)
		goto exit;
	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
		if (i < 6)
			chk_dbg = dma_dbg_4;
		else
			chk_dbg = dma_dbg_5;
		dcu_chain_state = (chk_dbg >> (5 * i)) & 0x1f;
		if (dcu_chain_state == 0x6) {
			dcu_wait_frdone = true;
			chk_dcu |= BIT(i);
		}
	}
	if ((dcu_complete_state == 0x1) && dcu_wait_frdone) {
		for_each_set_bit(i, &chk_dcu, ATH9K_NUM_TX_QUEUES) {
			if (ath9k_hw_verify_hang(ah, i))
				return true;
		}
	}
exit:
	return false;
}

The for loop seems to need to look like the following:

	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
               int off=i;
		if (i < 6) {
			chk_dbg = dma_dbg_4;
		} else {
			chk_dbg = dma_dbg_5;
                       off = i - 6;
               }
		dcu_chain_state = (chk_dbg >> (5 * off)) & 0x1f;
		if (dcu_chain_state == 0x6) {
			dcu_wait_frdone = true;
			chk_dcu |= BIT(i);
		}
	}

it would be best to have a constant declared that would be based on ATH9K_NUM_TX_QUEUES and the magical 32bits of space the declarations limit the calculations to.
it seem that the mask of 0x1f suggests that there are 5 bits per queue.  So there would be 2 bits left in dma_dbg_4 potentially, but the logic suggests that there are simply 6 groups of 5 bits in each of the registers without there being a split of the value across the 32-bit boundary.

Gregg Wonderly