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author | Matt Ettus <matt@ettus.com> | 2009-11-04 17:31:13 -0800 |
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committer | Matt Ettus <matt@ettus.com> | 2009-11-04 17:31:13 -0800 |
commit | 8f2c33eab9396185df259639082b7d1618585973 (patch) | |
tree | 87de89de85275b9155b41582813436929471a181 /control_lib/pic.v | |
parent | 1d933c9d263ca316d70a35adaba23f4112f370bb (diff) | |
download | uhd-8f2c33eab9396185df259639082b7d1618585973.tar.gz uhd-8f2c33eab9396185df259639082b7d1618585973.tar.bz2 uhd-8f2c33eab9396185df259639082b7d1618585973.zip |
This branch is for porting from the quad radio, and minor text cleanups
The counter is for performance monitoring in firmware, priority encoder
and new interrupt controller are from quad radio and speed up interrupts.
This is tested and it works for me.
Diffstat (limited to 'control_lib/pic.v')
-rw-r--r-- | control_lib/pic.v | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/control_lib/pic.v b/control_lib/pic.v new file mode 100644 index 000000000..9b9944d4a --- /dev/null +++ b/control_lib/pic.v @@ -0,0 +1,183 @@ + +// Heavily modified by M. Ettus, 2009, little original code remains +// Modified by M. Ettus, 2008 for 32 bit width + +///////////////////////////////////////////////////////////////////// +//// //// +//// OpenCores Simple Programmable Interrupt Controller //// +//// //// +//// Author: Richard Herveille //// +//// richard@asics.ws //// +//// www.asics.ws //// +//// //// +///////////////////////////////////////////////////////////////////// +//// //// +//// Copyright (C) 2002 Richard Herveille //// +//// richard@asics.ws //// +//// //// +//// This source file may be used and distributed without //// +//// restriction provided that this copyright statement is not //// +//// removed from the file and that any derivative work contains //// +//// the original copyright notice and the associated disclaimer.//// +//// //// +//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY //// +//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED //// +//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS //// +//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR //// +//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, //// +//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES //// +//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE //// +//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR //// +//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF //// +//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT //// +//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT //// +//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE //// +//// POSSIBILITY OF SUCH DAMAGE. //// +//// //// +///////////////////////////////////////////////////////////////////// +// +// This is a simple Programmable Interrupt Controller. +// The number of interrupts is depending on the databus size. +// There's one interrupt input per databit (i.e. 16 interrupts for a 16 +// bit databus). +// All attached devices share the same CPU priority level. +// +// +// +// Registers: +// +// 0x00: EdgeEnable Register +// bits 7:0 R/W Edge Enable '1' = edge triggered interrupt source +// '0' = level triggered interrupt source +// 0x01: PolarityRegister +// bits 7:0 R/W Polarity '1' = high level / rising edge +// '0' = low level / falling edge +// 0x02: MaskRegister +// bits 7:0 R/W Mask '1' = interrupt masked (disabled) +// '0' = interrupt not masked (enabled) +// 0x03: PendingRegister +// bits 7:0 R/W Pending '1' = interrupt pending +// '0' = no interrupt pending +// +// A CPU interrupt is generated when an interrupt is pending and its +// MASK bit is cleared. +// +// +// +// HOWTO: +// +// Clearing pending interrupts: +// Writing a '1' to a bit in the interrupt pending register clears the +// interrupt. Make sure to clear the interrupt at the source before +// writing to the interrupt pending register. Otherwise the interrupt +// will be set again. +// +// Priority based interrupts: +// Upon reception of an interrupt, check the interrupt register and +// determine the highest priority interrupt. Mask all interrupts from the +// current level to the lowest level. This negates the interrupt line, and +// makes sure only interrupts with a higher level are triggered. After +// completion of the interrupt service routine, clear the interrupt source, +// the interrupt bit in the pending register, and restore the MASK register +// to it's previous state. +// +// Addapt the core for fewer interrupt sources: +// If less than 8 interrupt sources are required, than the 'is' parameter +// can be set to the amount of required interrupts. Interrupts are mapped +// starting at the LSBs. So only the 'is' LSBs per register are valid. All +// other bits (i.e. the 8-'is' MSBs) are set to zero '0'. +// Codesize is approximately linear to the amount of interrupts. I.e. using +// 4 instead of 8 interrupt sources reduces the size by approx. half. +// + + +module pic + (input clk_i, input rst_i, input cyc_i, input stb_i, + input [2:0] adr_i, + input we_i, + input [31:0] dat_i, + output reg [31:0] dat_o, + output reg ack_o, + output reg int_o, + input [31:0] irq + ); + + reg [31:0] pol, edgen, pending, mask; // register bank + reg [31:0] lirq, dirq; // latched irqs, delayed latched irqs + + // latch interrupt inputs + always @(posedge clk_i) + lirq <= irq; + + // generate delayed latched irqs + always @(posedge clk_i) + dirq <= lirq; + + // generate actual triggers + function trigger; + input edgen, pol, lirq, dirq; + reg edge_irq, level_irq; + begin + edge_irq = pol ? (lirq & ~dirq) : (dirq & ~lirq); + level_irq = pol ? lirq : ~lirq; + trigger = edgen ? edge_irq : level_irq; + end + endfunction + + reg [31:0] irq_event; + integer n; + always @(posedge clk_i) + for(n = 0; n < 32; n = n+1) + irq_event[n] <= trigger(edgen[n], pol[n], lirq[n], dirq[n]); + + // generate wishbone register bank writes + wire wb_acc = cyc_i & stb_i; // WISHBONE access + wire wb_wr = wb_acc & we_i; // WISHBONE write access + + always @(posedge clk_i) + if (rst_i) + begin + pol <= 0; // clear polarity register + edgen <= 0; // clear edge enable register + mask <= 0; // mask all interrupts + end + else if(wb_wr) // wishbone write cycle?? + case (adr_i) // synopsys full_case parallel_case + 3'd0 : edgen <= dat_i; // EDGE-ENABLE register + 3'd1 : pol <= dat_i; // POLARITY register + 3'd2 : mask <= dat_i; // MASK register + 3'd3 : ; // PENDING register is a special case (see below) + 3'd4 : ; // Priority encoded live (pending & ~mask) + endcase + + // pending register is a special case + always @(posedge clk_i) + if (rst_i) + pending <= 0; // clear all pending interrupts + else if ( wb_wr & (adr_i == 3'd3) ) + pending <= (pending & ~dat_i) | irq_event; + else + pending <= pending | irq_event; + + wire [31:0] live_enc; + priority_enc priority_enc ( .in(pending & ~mask), .out(live_enc) ); + + always @(posedge clk_i) + case (adr_i) // synopsys full_case parallel_case + 3'd0 : dat_o <= edgen; + 3'd1 : dat_o <= pol; + 3'd2 : dat_o <= mask; + 3'd3 : dat_o <= pending; + 3'd4 : dat_o <= live_enc; + endcase + + always @(posedge clk_i) + ack_o <= wb_acc & !ack_o; + + always @(posedge clk_i) + if(rst_i) + int_o <= 0; + else + int_o <= |(pending & ~mask); + +endmodule |